Natrophylline Compound

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Natrophylline Compound uses

Natrophylline Compound consists of Aminophylline, Ephedrine Hydrochloride, Phenobarbital.

Aminophylline:



Natrophylline Compound (Aminophylline)

Injection, USP

25 mg/mL Natrophylline Compound (Aminophylline), Dihydrate

(Equivalent to 19.7 mg/mL of Anhydrous Theophylline)

Ampul

Fliptop Vial Rx only

DESCRIPTION

Natrophylline Compound (Aminophylline) Injection, USP is a sterile, nonpyrogenic solution of Natrophylline Compound (Aminophylline) in water for injection. Natrophylline Compound (Aminophylline) (dihydrate) is approximately 79% of anhydrous theophylline by weight. Natrophylline Compound (Aminophylline) Injection is administered by slow intravenous injection or diluted and administered by intravenous infusion.

The solution contains no bacteriostat or antimicrobial agent and is intended for use only as a single-dose injection. When smaller doses are required the unused portion should be discarded.

Natrophylline Compound (Aminophylline) is a 2:1 complex of theophylline and ethylenediamine. Theophylline is structurally classified as a methylxanthine. Natrophylline Compound (Aminophylline) occurs as a white or slightly yellowish granule or powder, with a slight ammoniacal odor. Natrophylline Compound (Aminophylline) has the chemical name 1H-Purine-2, 6-dione, 3,7-dihydro-1,3-dimethyl-, compound with 1,2-ethanediamine (2:1). The structural formula of Natrophylline Compound (Aminophylline) (dihydrate) is as follows:

The molecular formula of Natrophylline Compound (Aminophylline) dihydrate is C16H24N10O4 - 2(H2O) with a molecular weight of 456.46.

Natrophylline Compound (Aminophylline) Injection, USP contains Natrophylline Compound (Aminophylline) (calculated as the dihydrate) 25 mg/mL (equivalent to 19.7 mg/mL anhydrous theophylline) prepared with the aid of ethylenediamine. The solution may contain an excess of ethylenediamine for pH adjustment. pH is 8.8 (8.6 to 9.0). The osmolar concentration is 0.17 mOsmol/mL (calc.).

structural formula Natrophylline Compound (Aminophylline)

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CLINICAL PHARMACOLOGY

Mechanism of Action:

Theophylline has two distinct actions in the airways of patients with reversible obstruction; smooth muscle relaxation and suppression of the response of the airways to stimuli (i.e., nonbronchodilator prophylactic effects). While the mechanisms of action of theophylline are not known with certainty, studies in animals suggest that bronchodilation is mediated by the inhibition of two isozymes of phosphodiesterase (PDE III and, to a lesser extent, PDE IV), while nonbronchodilator prophylactic actions are probably mediated through one or more different molecular mechanisms, that do not involve inhibition of PDE III or antagonism of adenosine receptors. Some of the adverse effects associated with theophylline appear to be mediated by inhibition of PDE III (e.g., hypotension, tachycardia, headache, and emesis) and adenosine receptor antagonism (e.g., alterations in cerebral blood flow).

Theophylline increases the force of contraction of diaphragmatic muscles. This action appears to be due to enhancement of calcium uptake through an adenosine-mediated channel.

Serum Concentration-Effect Relationship:

Bronchodilation occurs over the serum theophylline concentration range of 5 - 20 mcg/mL. Clinically important improvement in symptom control and pulmonary function has been found in most studies to require serum theophylline concentrations >10 mcg/mL. At serum theophylline concentrations >20 mcg/mL, both the frequency and severity of adverse reactions increase. In general, maintaining the average serum theophylline concentration between 10 and 15 mcg/mL will achieve most of the drug's potential therapeutic benefit while minimizing the risk of serious adverse events.

Pharmacokinetics:

Overview The pharmacokinetics of theophylline vary widely among similar patients and cannot be predicted by age, sex, body weight or other demographic characteristics. In addition, certain concurrent illnesses and alterations in normal physiology (see Table I ) and co-administration of other drugs (see Table II ) can significantly alter the pharmacokinetic characteristics of theophylline. Within-subject variability in metabolism has also been reported in some studies, especially in acutely ill patients.

It is, therefore, recommended that serum theophylline concentrations be measured frequently in acutely ill patients receiving intravenous theophylline (e.g., at 24-hr. intervals). More frequent measurements should be made during the initiation of therapy and in the presence of any condition that may significantly alter theophylline clearance (see PRECAUTIONS , Effects on Laboratory Tests ).

¶ For various North American patient populations from literature reports. Different rates of elimination and consequent dosage requirements have been observed among other peoples.

* Clearance represents the volume of blood completely cleared of theophylline by the liver in one minute. Values listed were generally determined at serum theophylline concentrations, <20 mcg/mL; clearance may decrease and half-life may increase at higher serum concentrations due to nonlinear pharmacokinetics.

†† Reported range or estimated range (mean ± 2 SD) where actual range not reported.

NR = not reported or not reported in a comparable format.

** Median




Population Characteristics

Age


Total Body Clearance*

Mean (Range)††

(mL/kg/min)


Half-Life

Mean (Range)††

(hr)


Premature neonates

postnatal age 3 - 15 days

postnatal age 25 - 57 days



0.29 (0.09 - 0.49)

0.64 (0.04 - 1.2)



30 (17 - 43)

20 (9.4 - 30.6)


Term infants

postnatal age 1 - 2 days

postnatal age 3 - 30 weeks



NR

NR



25.7 (25 - 26.5)

11 (6 - 29)


Children

1 - 4 years

4 - 12 years

13 - 15 years

6 - 17 years



1.7 (0.5 - 2.9)

1.6 (0.8 - 2.4)

0.9 (0.48 - 1.3)

1.4 (0.2 - 2.6)



3.4 (1.2 - 5.6)

NR

NR

3.7 (1.5 - 5.9)


Adults (16 - 60 years)

otherwise healthy

nonsmoking asthmatics




0.65 (0.27 - 1.03)




8.7 (6.1 - 12.8)


Elderly (>60 years)

nonsmokers with normal cardiac,

liver, and renal function




0.41 (0.21 - 0.61)




9.8 (1.6 - 18)


Concurrent Illness Or Altered Physiological State


Acute pulmonary edema


0.33** (0.07 - 2.45)


19** (3.1 - 8.2)


COPD- >60 years, stable

nonsmoker >1 year



0.54 (0.44 - 0.64)



11 (9.4 - 12.6)


COPD with cor pulmonale


0.48 (0.08 - 0.88)


NR


Cystic fibrosis (14 - 28 years)


1.25 (0.31 - 2.2)


6 (1.8 - 10.2)


Fever associated with acute viral respiratory


illness (children 9 - 15 years)


NR


7 (1.0 - 13)


Liver disease – cirrhosis

acute hepatitis

cholestasis


0.31** (0.1 - 0.7)

0.35 (0.25 - 0.45)

0.65 (0.25 - 1.45)


32** (10 - 56)

19.2 (16.6 - 21.8)

14.4 (5.7 - 31.8)


Pregnancy – 1st trimester

2nd trimester

3rd trimester


NR

NR

NR


8.5 (3.1 - 13.9)

8.8 (3.8 - 13.8)

13 (8.4 - 17.6)


Sepsis with multi-organ failure


0.47 (0.19 - 1.9)


18.8 (6.3 - 24.1)


Thyroid disease – hypothyroid

hyperthyroid


0.38 (0.13 - 0.57)

0.8 (0.68 - 0.97)


11.6 (8.2 - 25)

4.5 (3.7 - 5.6)


Note: In addition to the factors listed above, theophylline clearance is increased and half-life decreased by low carbohydrate/high protein diets, parenteral nutrition, and daily consumption of charcoal-broiled beef. A high carbohydrate/low protein diet can decrease the clearance and prolong the half-life of theophylline.

Distribution Once theophylline enters the systemic circulation, about 40% is bound to plasma protein, primarily albumin. Unbound theophylline distributes throughout body water, but distributes poorly into body fat. The apparent volume of distribution of theophylline is approximately 0.45 L/kg (range 0.3 - 0.7 L/kg) based on ideal body weight. Theophylline passes freely across the placenta, into breast milk and into the cerebrospinal fluid (CSF). Saliva theophylline concentrations approximate unbound serum concentrations, but are not reliable for routine or therapeutic monitoring unless special techniques are used. An increase in the volume of distribution of theophylline, primarily due to reduction in plasma protein binding, occurs in premature neonates, patients with hepatic cirrhosis, uncorrected acidemia, the elderly and in women during the third trimester of pregnancy. In such cases, the patient may show signs of toxicity at total (bound + unbound) serum concentrations of theophylline in the therapeutic range (10 - 20 mcg/mL) due to elevated concentrations of the pharmacologically active unbound drug. Similarly, a patient with decreased theophylline binding may have a sub-therapeutic total drug concentration while the pharmacologically active unbound concentration is in the therapeutic range. If only total serum theophylline concentration is measured, this may lead to an unnecessary and potentially dangerous dose increase. In patients with reduced protein binding, measurement of unbound serum theophylline concentration provides a more reliable means of dosage adjustment than measurement of total serum theophylline concentration. Generally, concentrations of unbound theophylline should be maintained in the range of 6 - 12 mcg/mL.

Metabolism In adults and children beyond one year of age, approximately 90% of the dose is metabolized in the liver. Biotransformation takes place through demethylation to 1-methylxanthine and 3-methylxanthine and hydroxylation to 1,3-dimethyluric acid. 1-methylxanthine is further hydroxylated, by xanthine oxidase, to 1-methyluric acid. About 6% of a theophylline dose is N-methylated to caffeine. Theophylline demethylation to 3-methylxanthine is catalyzed by cytochrome P-450 1A2, while cytochromes P-450 2E1 and P-450 3A3 catalyze the hydroxylation to 1,3-dimethyluric acid. Demethylation to 1-methylxanthine appears to be catalyzed either by cytochrome P-450 1A2 or a closely related cytochrome. In neonates, the N-demethylation pathway is absent while the function of the hydroxylation pathway is markedly deficient. The activity of these pathways slowly increases to maximal levels by one year of age.

Caffeine and 3-methylxanthine are the only theophylline metabolites with pharmacologic activity. 3-methylxanthine has approximately one tenth the pharmacologic activity of theophylline and serum concentrations in adults with normal renal function are <1 mcg/mL. In patients with end-stage renal disease, 3-methylxanthine may accumulate to concentrations that approximate the unmetabolized theophylline concentration. Caffeine concentrations are usually undetectable in adults regardless of renal function. In neonates, caffeine may accumulate to concentrations that approximate the unmetabolized theophylline concentration and thus, exert a pharmacologic effect.

Both the N-demethylation and hydroxylation pathways of theophylline biotransformation are capacity-limited. Due to the wide intersubject variability of the rate of theophylline metabolism, nonlinearity of elimination may begin in some patients at serum theophylline concentrations <10 mcg/mL. Since this nonlinearity results in more than proportional changes in serum theophylline concentrations with changes in dose, it is advisable to make increases or decreases in dose in small increments in order to achieve desired changes in serum theophylline concentrations (See DOSAGE AND ADMINISTRATION , Table VI ). Accurate prediction of dose-dependency of theophylline metabolism in patients a priori is not possible, but patients with very high initial clearance rates (i.e., low steady state serum theophylline concentrations at above average doses) have the greatest likelihood of experiencing large changes in serum theophylline concentration in response to dosage changes.

Excretion In neonates, approximately 50% of the theophylline dose is excreted unchanged in the urine. Beyond the first three months of life, approximately 10% of the theophylline dose is excreted unchanged in the urine. The remainder is excreted in the urine mainly as 1,3-dimethyluric acid (35 - 40%), 1-methyluric acid (20 - 25%) and 3-methylxanthine (15 - 20%). Since little theophylline is excreted unchanged in the urine and since active metabolites of theophylline (i.e., caffeine, 3-methylxanthine) do not accumulate to clinically significant levels even in the face of end-stage renal disease, no dosage adjustment for renal insufficiency is necessary in adults and children >3 months of age. In contrast, the large fraction of the theophylline dose excreted in the urine as unchanged theophylline and caffeine in neonates requires careful attention to dose reduction and frequent monitoring of serum theophylline concentrations in neonates with reduced renal function (see WARNINGS ).

Serum Concentrations at Steady State In a patient who has received no theophylline in the previous 24 hours, a loading dose of intravenous theophylline of 4.6 mg/kg (5.7 mg/kg as Natrophylline Compound (Aminophylline)), calculated on the basis of ideal body weight and administered over 30 minutes, on average, will produce a maximum post-distribution serum concentration of 10 mcg/mL with a range of 6-16 mcg/mL. In non-smoking adults, initiation of a constant intravenous theophylline infusion of 0.4 mg/kg/hr (0.5 mg/kg/hr as Natrophylline Compound (Aminophylline)) at the completion of the loading dose, on average, will result in a steady-state concentration of 10 mcg/mL with a range of 7-26 mcg/mL. The mean and range of steady-state serum concentrations are similar when the average child (age 1 to 9 years) is given a loading dose of 4.6 mg/kg theophylline (5.7 mg/kg as Natrophylline Compound (Aminophylline)) followed by a constant intravenous infusion of 0.8 mg/kg/hr (1.0 mg/kg/hr as Natrophylline Compound (Aminophylline)). (See DOSAGE AND ADMINISTRATION .)

Special Populations (See Table I for mean clearance and half-life values)

Geriatric The clearance of theophylline is decreased by an average of 30% in healthy elderly adults (>60 yrs.) compared to healthy young adults. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in elderly patients (see WARNINGS ).

Pediatrics The clearance of theophylline is very low in neonates (see WARNINGS ). Theophylline clearance reaches maximal values by one year of age, remains relatively constant until about 9 years of age and then slowly decreases by approximately 50% to adult values at about age 16. Renal excretion of unchanged theophylline in neonates amounts to about 50% of the dose, compared to about 10% in children older than three months and in adults. Careful attention to dosage selection and monitoring of serum theophylline concentrations are required in children (see WARNINGS and DOSAGE AND ADMINISTRATION ).

Gender Gender differences in theophylline clearance are relatively small and unlikely to be of clinical significance. Significant reduction in theophylline clearance, however, has been reported in women on the 20th day of the menstrual cycle and during the third trimester of pregnancy.

Race Pharmacokinetic differences in theophylline clearance due to race have not been studied.

Renal Insufficiency Only a small fraction, e.g., about 10%, of the administered theophylline dose is excreted unchanged in the urine of children greater than three months of age and adults. Since little theophylline is excreted unchanged in the urine and since active metabolites of theophylline (i.e., caffeine, 3-methylxanthine) do not accumulate to clinically significant levels even in the face of end-stage renal disease, no dosage adjustment for renal insufficiency is necessary in adults and children >3 months of age. In contrast, approximately 50% of the administered theophylline dose is excreted unchanged in the urine in neonates. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in neonates with decreased renal function (see WARNINGS ).

Hepatic Insufficiency Theophylline clearance is decreased by 50% or more in patients with hepatic insufficiency (e.g., cirrhosis, acute hepatitis, cholestasis). Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in patients with reduced hepatic function (see WARNINGS ).

Congestive Heart Failure (CHF) Theophylline clearance is decreased by 50% or more in patients with CHF. The extent of reduction in theophylline clearance in patients with CHF appears to be directly correlated to the severity of the cardiac disease. Since theophylline clearance is independent of liver blood flow, the reduction in clearance appears to be due to impaired hepatocyte function rather than reduced perfusion. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in patients with CHF (see WARNINGS ).

Smokers Tobacco and marijuana smoking appears to increase the clearance of theophylline by induction of metabolic pathways. Theophylline clearance has been shown to increase by approximately 50% in young adult tobacco smokers and by approximately 80% in elderly tobacco smokers compared to nonsmoking subjects. Passive smoke exposure has also been shown to increase theophylline clearance by up to 50%. Abstinence from tobacco smoking for one week causes a reduction of approximately 40% in theophylline clearance. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in patients who stop smoking (see WARNINGS ). Use of nicotine gum has been shown to have no effect on theophylline clearance.

Fever Fever, regardless of its underlying cause, can decrease the clearance of theophylline. The magnitude and duration of the fever appear to be directly correlated to the degree of decrease of theophylline clearance. Precise data are lacking, but a temperature of 39°C (102°F) for at least 24 hours is probably required to produce a clinically significant increase in serum theophylline concentrations. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in patients with sustained fever (see WARNINGS ).

Miscellaneous Other factors associated with decreased theophylline clearance include the third trimester of pregnancy, sepsis with multiple organ failure, and hypothyroidism. Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in patients with any of these conditions (see WARNINGS ). Other factors associated with increased theophylline clearance include hyperthyroidism and cystic fibrosis.

Clinical Studies:

Inhaled beta-2 selective agonists and systemically administered corticosteroids are the treatments of first choice for management of acute exacerbations of asthma. The results of controlled clinical trials on the efficacy of adding intravenous theophylline to inhaled beta-2 selective agonists and systemically administered corticosteroids in the management of acute exacerbations of asthma have been conflicting. Most studies in patients treated for acute asthma exacerbations in an emergency department have shown that addition of intravenous theophylline does not produce greater bronchodilation and increases the risk of adverse effects. In contrast, other studies have shown that addition of intravenous theophylline is beneficial in the treatment of acute asthma exacerbations in patients requiring hospitalization, particularly in patients who are not responding adequately to inhaled beta-2 selective agonists.

In patients with chronic obstructive pulmonary disease (COPD), clinical studies have shown that theophylline decreases dyspnea, air trapping, the work of breathing, and improves contractility of diaphragmatic muscles with little or no improvement in pulmonary function measurements.

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INDICATIONS AND USAGE

Intravenous theophylline is indicated as an adjunct to inhaled beta-2 selective agonists and systemically administered corticosteroids for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

CONTRAINDICATIONS

Natrophylline Compound (Aminophylline) is contraindicated in patients with a history of hypersensitivity to theophylline or other components in the product including ethylenediamine.

WARNINGS

Concurrent Illness:

Theophylline should be used with extreme caution in patients with the following clinical conditions due to the increased risk of exacerbation of the concurrent condition:

Active peptic ulcer disease

Seizure disorders

Cardiac arrhythmias

Conditions That Reduce Theophylline Clearance:

There are several readily identifiable causes of reduced theophylline clearance. If the infusion rate is not appropriately reduced in the presence of these risk factors, severe and potentially fatal theophylline toxicity can occur. Careful consideration must be given to the benefits and risks of theophylline use and the need for more intensive monitoring of serum theophylline concentrations in patients with the following risk factors:

Age

Neonates (term and premature)

Children <1 year

Elderly (>60 years)

Concurrent Diseases

Acute pulmonary edema

Congestive heart failure

Cor pulmonale

Fever; ≥102° for 24 hours or more; or lesser temperature

elevations for longer periods

Hypothyroidism

Liver disease; cirrhosis, acute hepatitis

Reduced renal function in infants <3 months of age

Sepsis with multi-organ failure

Shock

Cessation of Smoking

Drug Interactions

Adding a drug that inhibits theophylline metabolism (e.g., cimetidine, erythromycin, tacrine) or stopping a concurrently administered drug that enhances theophylline metabolism (e.g., carbamazepine, rifampin). (See PRECAUTIONS , Drug Interactions, Table II .)

When Signs or Symptoms of Theophylline Toxicity Are Present:

Whenever a patient receiving theophylline develops nausea or vomiting, particularly repetitive vomiting, or other signs or symptoms consistent with theophylline toxicity (even if another cause may be suspected), the intravenous infusion should be stopped and a serum theophylline concentration measured immediately.

Dosage Increases

Increases in the dose of intravenous theophylline should not be made in response to an acute exacerbation of symptoms unless the steady-state serum theophylline concentration is <10 mcg/mL.

As the rate of theophylline clearance may be dose-dependent (i.e., steady-state serum concentrations may increase disproportionately to the increase in dose), an increase in dose based upon a sub-therapeutic serum concentration measurement should be conservative. In general, limiting infusion rate increases to about 25% of the previous infusion rate will reduce the risk of unintended excessive increases in serum theophylline concentration (see DOSAGE AND ADMINISTRATION , TABLE VI ).

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PRECAUTIONS

General

Careful consideration of the various interacting drugs and physiologic conditions that can alter theophylline clearance and require dosage adjustment should occur prior to initiation of theophylline therapy and prior to increases in theophylline dose.

Monitoring Serum Theophylline Concentrations:

Serum theophylline concentration measurements are readily available and should be used to determine whether the dosage is appropriate. Specifically, the serum theophylline concentration should be measured as follows:

  • Before making a dose increase to determine whether the serum concentration is sub-therapeutic in a patient who continues to be symptomatic.
  • Whenever signs or symptoms of theophylline toxicity are present.
  • Whenever there is a new illness, worsening of an existing concurrent illness or a change in the patient's treatment regimen that may alter theophylline clearance (e.g., fever >102°F sustained for ≥24 hours, hepatitis, or drugs listed in Table II are added or discontinued).

In patients who have received no theophylline in the previous 24 hours, a serum concentration should be measured 30 minutes after completion of the intravenous loading dose to determine whether the serum concentration is <10 mcg/mL indicating the need for an additional loading dose or >20 mcg/mL indicating the need to delay starting the constant I.V. infusion. Once the infusion is begun, a second measurement should be obtained after one expected half-life (e.g., approximately 4 hours in children 1 to 9 years and 8 hours in non-smoking adults; See Table I for the expected half-life in additional patient populations). The second measurement should be compared to the first to determine the direction in which the serum concentration has changed. The infusion rate can then be adjusted before steady state is reached in an attempt to prevent an excessive or sub-therapeutic theophylline concentration from being achieved.

If a patient has received theophylline in the previous 24 hours, the serum concentration should be measured before administering an intravenous loading dose to make sure that it is safe to do so. If a loading dose is not indicated (i.e., the serum theophylline concentration is ≥10 mcg/mL), a second measurement should be obtained as above at the appropriate time after starting the intravenous infusion. If, on the other hand, a loading dose is indicated (See DOSAGE AND ADMINISTRATION for guidance on selection of the appropriate loading dose), a second blood sample should be obtained after the loading dose and a third sample should be obtained one expected half-life after starting the constant infusion to determine the direction in which the serum concentration has changed.

Once the above procedures related to initiation of intravenous theophylline infusion have been completed, subsequent serum samples for determination of theophylline concentration should be obtained at 24-hour intervals for the duration of the infusion. The theophylline infusion rate should be increased or decreased as appropriate based on the serum theophylline levels.

When signs or symptoms of theophylline toxicity are present, the intravenous infusion should be stopped and a serum sample for theophylline concentration should be obtained as soon as possible, analyzed immediately, and the result reported to the clinician without delay. In patients in whom decreased serum protein binding is suspected (e.g., cirrhosis, women during the third trimester of pregnancy), the concentration of unbound theophylline should be measured and the dosage adjusted to achieve an unbound concentration of 6-12 mcg/mL.

Saliva concentrations of theophylline cannot be used reliably to adjust dosage without special techniques.

Effects on Laboratory Tests:

As a result of its pharmacological effects, theophylline at serum concentrations within the 10 - 20 mcg/mL range modestly increases plasma glucose (from a mean of 88 mg% to 98 mg%), uric acid (from a mean of 4 mg/dl to 6 mg/dl), free fatty acids (from a mean of 451 µEq/L to 800 µEq/L), total cholesterol (from a mean of 140 vs 160 mg/dl), HDL (from a mean of 36 to 50 mg/dl), HDL/LDL ratio (from a mean of 0.5 to 0.7), and urinary free cortisol excretion (from a mean of 44 to 63 mcg/24 hr). Theophylline at serum concentrations within the 10 - 20 mcg/mL range may also transiently decrease serum concentrations of triiodothyronine (144 before, 131 after one week and 142 ng/dl after 4 weeks of theophylline). The clinical importance of these changes should be weighed against the potential therapeutic benefit of theophylline in individual patients.

Drug Interactions:

Theophylline interacts with a wide variety of drugs. The interaction may be pharmacodynamic, i.e., alterations in the therapeutic response to theophylline or another drug or occurrence of adverse effects without a change in serum theophylline concentration. More frequently, however, the interaction is pharmacokinetic, i.e., the rate of theophylline clearance is altered by another drug resulting in increased or decreased serum theophylline concentrations. Theophylline only rarely alters the pharmacokinetics of other drugs.

The drugs listed in Table II have the potential to produce clinically significant pharmacodynamic or pharmacokinetic interactions with theophylline. The information in the "Effect" column of Table II assumes that the interacting drug is being added to a steady-state theophylline regimen. If theophylline is being initiated in a patient who is already taking a drug that inhibits theophylline clearance, the dose of theophylline required to achieve a therapeutic serum theophylline concentration will be smaller. Conversely, if theophylline is being initiated in a patient who is already taking a drug that enhances theophylline clearance (e.g., rifampin), the dose of theophylline required to achieve a therapeutic serum theophylline concentration will be larger. Discontinuation of a concomitant drug that increases theophylline clearance will result in accumulation of theophylline to potentially toxic levels, unless the theophylline dose is appropriately reduced. Discontinuation of a concomitant drug that inhibits theophylline clearance will result in decreased serum theophylline concentrations, unless the theophylline dose is appropriately increased.

The drugs listed in Table III have either been documented not to interact with theophylline or do not produce a clinically significant interaction (i.e., <15% change in theophylline clearance).

The listing of drugs in Tables II and III are current as of September 1, 1995. New interactions are continuously being reported for theophylline, especially with new chemical entities. The clinician should not assume that a drug does not interact with theophylline if it is not listed in Table II . Before addition of a newly available drug in a patient receiving theophylline, the package insert of the new drug and/or the medical literature should be consulted to determine if an interaction between the new drug and theophylline has been reported.

Drug Type Of Interaction Effect**
* Refer to PRECAUTIONS , Drug Interactions for further information regarding table.

** Average effect on steady-state theophylline concentration or other clinical effect for pharmacologic interactions. Individual patients may experience larger changes in serum theophylline concentration than the value listed.


Adenosine


Theophylline blocks adenosine receptors.


Higher doses of adenosine may be required to achieve desired effect.


Alcohol


A single large dose of alcohol (3 mL/kg of whiskey) decreases theophylline clearance for up to 24 hours.


30% increase


Allopurinol


Decreases theophylline clearance at allopurinol doses ≥600 mg/day.


25% increase


Aminoglutethimide


Increases theophylline clearance by induction of microsomal enzyme activity.


25% decrease


Carbamazepine


Similar to aminoglutethimide.


30% decrease


Cimetidine


Decreases theophylline clearance by inhibiting cytochrome P450 1A2.


70% increase


Ciprofloxacin


Similar to cimetidine.


40% increase


Clarithromycin


Similar to erythromycin.


25% increase


Diazepam


Benzodiazepines increase CNS concentrations of adenosine, a potent CNS depressant, while theophylline blocks adenosine receptors.


Larger diazepam doses may be required to produce desired level of sedation. Discontinuation of theophylline without reduction of diazepam dose may result in respiratory depression.


Disulfiram


Decreases theophylline clearance by inhibiting hydroxylation and demethylation.


50% increase


Enoxacin


Similar to cimetidine.


300% increase


Ephedrine


Synergistic CNS effects.


Increased frequency of nausea, nervousness, and insomnia.


Erythromycin


Erythromycin metabolite decreases theophylline clearance by inhibiting

cytochrome P450 3A3.


35% increase. Erythromycin steady-state serum concentrations decrease by a similar amount.


Estrogen


Estrogen containing oral contraceptives decrease theophylline clearance in a dose-dependent fashion.

The effect of progesterone on theophylline clearance is unknown.


30% increase


Flurazepam


Similar to diazepam.


Similar to diazepam.


Fluvoxamine


Similar to cimetidine.


Similar to cimetidine.


Halothane


Halothane sensitizes the myocardium to catecholamines, theophylline increases release of endogenous catecholamines.


Increased risk of ventricular arrhythmias.


Interferon, human recombinant alpha-A


Decreases theophylline clearance.


100% increase


Isoproterenol (I.V.)


Increases theophylline clearance.


20% decrease


Ketamine


Pharmacologic


May lower theophylline seizure threshold.


Lithium


Theophylline increases renal lithium clearance.


Lithium dose required to achieve a therapeutic serum concentration increased an average of 60%.


Lorazepam


Similar to diazepam.


Similar to diazepam.


Methotrexate (MTX)


Decreases theophylline clearance.


20% increase after low dose MTX, higher dose MTX may have a greater effect.


Mexiletine


Similar to disulfiram.


80% increase


Midazolam


Similar to diazepam.


Similar to diazepam.


Moricizine


Increases theophylline clearance.


25% decrease


Pancuronium


Theophylline may antagonize nondepolarizing neuromuscular blocking effects; possibly due to phosphodiesterase inhibition.


Larger dose of pancuronium may be required to achieve neuromuscular blockade.


Pentoxifylline


Decreases theophylline clearance.


30% increase


Phenobarbital (PB)


Similar to aminoglutethimide.


25% decrease after two weeks of concurrent Phenobarbital.


Phenytoin


Phenytoin increases theophylline clearance by increasing microsomal enzyme activity. Theophylline decreases phenytoin absorption.


Serum theophylline and phenytoin concentrations decrease about 40%.


Propafenone


Decreases theophylline clearance and pharmacologic interaction.


40% increase. Beta-2 blocking effect may decrease efficacy of theophylline.


Propranolol


Similar to cimetidine and pharmacologic interaction.


100% increase. Beta-2 blocking effect may decrease efficacy of theophylline.


Rifampin


Increases theophylline clearance by increasing cytochrome P450 1A2 and 3A3 activity.


20 - 40% decrease


Sulfinpyrazone


Increases theophylline clearance by increasing demethylation and hydroxylation. Decreases renal clearance of theophylline.


20% decrease


Tacrine


Similar to cimetidine, also increases renal clearance of theophylline.


90% increase


Thiabendazole


Decreases theophylline clearance.


190% increase


Ticlopidine


Decreases theophylline clearance.


60% increase


Troleandomycin


Similar to erythromycin.


33 - 100% increase depending on troleandomycin dose.


Verapamil


Similar to disulfiram.


20% increase


albuterol,

systemic and inhaled

amoxicillin

ampicillin,

with or without sulbactam

atenolol

azithromycin

caffeine,

dietary ingestion

cefaclor

co-trimoxazole

(trimethoprim and sulfamethoxazole)

diltiazem

dirithromycin

enflurane

famotidine

felodipine

finasteride

hydrocortisone

isoflurane

isoniazid

isradipine

influenza vaccine

ketoconazole


lomefloxacin

mebendazole

medroxyprogesterone

methylprednisolone

metronidazole

metoprolol

nadolol

nifedipine

nizatidine

norfloxacin

ofloxacin

omeprazole

prednisone, prednisolone

ranitidine

rifabutin

roxithromycin

sorbitol

(purgative doses do not inhibit

theophylline absorption)

sucralfate

terbutaline, systemic

terfenadine

tetracycline

tocainide


The Effect of Other Drugs on Theophylline Serum Concentration Measurements:

Most serum theophylline assays in clinical use are immunoassays which are specific for theophylline. Other xanthines such as caffeine, dyphylline, and pentoxifylline are not detected by these assays. Some drugs (e.g., cefazolin, cephalothin), however, may interfere with certain HPLC techniques. Caffeine and xanthine metabolites in neonates or patients with renal dysfunction may cause the reading from some dry reagent office methods to be higher than the actual serum theophylline concentration.

Carcinogenesis, Mutagenesis, and Impairment of Fertility:

Long term carcinogenicity studies have been carried out in mice (oral doses 30 - 150 mg/kg) and rats (oral doses 5 - 75 mg/kg). Results are pending.

Theophylline has been studied in Ames salmonella, in vivo and in vitro cytogenetics, micronucleus and Chinese hamster ovary test systems and has not been shown to be genotoxic.

In a 14 week continuous breeding study, theophylline, administered to mating pairs of B6C3F1 mice at oral doses of 120, 270 and 500 mg/kg (approximately 1.0 - 3.0 times the human dose on a mg/m2 basis) impaired fertility, as evidenced by decreases in the number of live pups per litter, decreases in the mean number of litters per fertile pair, and increases in the gestation period at the high dose as well as decreases in the proportion of pups born alive at the mid and high dose. In 13 week toxicity studies, theophylline was administered to F344 rats and B6C3F1 mice at oral doses of 40 - 300 mg/kg (approximately 2 times the human dose on a mg/m2 basis). At the high dose, systemic toxicity was observed in both species including decreases in testicular weight.

Pregnancy:

Category C: There are no adequate and well controlled studies in pregnant women. Additionally, there are no teratogenicity studies in nonrodents. Theophylline was not shown to be teratogenic in CD-1 mice at oral doses up to 400 mg/kg, approximately 2.0 times the human dose on a mg/m2 basis or in CD-1 rats at oral doses up to 260 mg/kg, approximately 3.0 times the recommended human dose on a mg/m2 basis. At a dose of 220 mg/kg, embryotoxicity was observed in rats in the absence of maternal toxicity.

Nursing Mothers:

Theophylline is excreted into breast milk and may cause irritability or other signs of mild toxicity in nursing human infants. The concentration of theophylline in breast milk is about equivalent to the maternal serum concentration. An infant ingesting a liter of breast milk containing 10 - 20 mcg/mL of theophylline per day is likely to receive 10 - 20 mg of theophylline per day. Serious adverse effects in the infant are unlikely unless the mother has toxic serum theophylline concentrations.

Pediatric Use:

Theophylline is safe and effective for the approved indications in pediatric patients. The constant infusion rate of intravenous theophylline must be selected with caution in pediatric patients since the rate of theophylline clearance is highly variable across the age range of neonates to adolescents (see CLINICAL PHARMACOLOGY , Table I , WARNINGS , and DOSAGE AND ADMINISTRATION , Table V ). Due to the immaturity of theophylline metabolic pathways in pediatric patients under the age of one year, particular attention to dosage selection and frequent monitoring of serum theophylline concentrations are required when theophylline is prescribed to pediatric patients in this age group.

Geriatric Use:

Elderly patients are at significantly greater risk of experiencing serious toxicity from theophylline than younger patients due to pharmacokinetic and pharmacodynamic changes associated with aging. Theophylline clearance is reduced in patients greater than 60 years of age, resulting in increased serum theophylline concentrations in response to a given theophylline infusion rate. Protein binding may be decreased in the elderly resulting in a larger proportion of the total serum theophylline concentration in the pharmacologically active unbound form. Elderly patients also appear to be more sensitive to the toxic effects of theophylline after chronic overdosage than younger patients. For these reasons, the maximum infusion rate of theophylline in patients greater than 60 years of age ordinarily should not exceed 17 mg/hr (21 mg/hr as Natrophylline Compound (Aminophylline)) unless the patient continues to be symptomatic and the peak steady state serum theophylline concentration is <10 mcg/mL (see DOSAGE AND ADMINISTRATION ). Theophylline infusion rates greater than 17 mg/hr (21 mg/hr as Natrophylline Compound (Aminophylline)) should be prescribed with caution in elderly patients.

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ADVERSE REACTIONS

Adverse reactions associated with theophylline are generally mild when peak serum theophylline concentrations are <20 mcg/mL and mainly consist of transient caffeine-like adverse effects such as nausea, vomiting, headache, and insomnia. When peak serum theophylline concentrations exceed 20 mcg/mL, however, theophylline produces a wide range of adverse reactions including persistent vomiting, cardiac arrhythmias, and intractable seizures which can be lethal (see OVERDOSAGE ).

Other adverse reactions that have been reported at serum theophylline concentrations <20 mcg/mL include diarrhea, irritability, restlessness, fine skeletal muscle tremors, and transient diuresis. In patients with hypoxia secondary to COPD, multifocal atrial tachycardia and flutter have been reported at serum theophylline concentrations ≥15 mcg/mL. There have been a few isolated reports of seizures at serum theophylline concentrations <20 mcg/mL in patients with an underlying neurological disease or in elderly patients. The occurrence of seizures in elderly patients with serum theophylline concentrations <20 mcg/mL may be secondary to decreased protein binding resulting in a larger proportion of the total serum theophylline concentration in the pharmacologically active unbound form. The clinical characteristics of the seizures reported in patients with serum theophylline concentrations <20 mcg/mL have generally been milder than seizures associated with excessive serum theophylline concentrations resulting from an overdose (i.e., they have generally been transient, often stopped without anticonvulsant therapy, and did not result in neurological residua).

Products containing Natrophylline Compound (Aminophylline) may rarely produce severe allergic reactions of the skin, including exfoliative dermatitis, after systemic administration in a patient who has been previously sensitized by topical application of a substance containing ethylenediamine. In such patients skin patch tests are positive for ethylenediamine, a component of Natrophylline Compound (Aminophylline), and negative for theophylline. Pharmacists and other individuals who experience repeated skin exposure while physically handling Natrophylline Compound (Aminophylline) may develop a contact dermatitis due to the ethylenediamine component.

* These data are derived from two studies in patients with serum theophylline concentrations

>30 mcg/mL. In the first study (Study #1 – Shanon, Ann Intern Med 1993;119:1161-67), data were prospectively collected from 249 consecutive cases of theophylline toxicity referred to a regional poison center for consultation. In the second study (Study #2 – Sessler, Am J Med 1990; 88:567-76), data were retrospectively collected from 116 cases with serum theophylline concentrations >30 mcg/mL among 6000 blood samples obtained for measurement of serum theophylline concentrations in three emergency departments. Differences in the incidence of manifestations of theophylline toxicity between the two studies may reflect sample selection as a result of study design (e.g., in Study #1, 48% of the patients had acute intoxications versus only 10% in Study #2) and different methods of reporting results.

** NR = Not reported in a comparable manner.


Acute Overdose

(Large Single Ingestion)


Chronic Overdosage

(Multiple Excessive Doses)


Sign/Symptom


Study 1

(n=157)


Study 2

(n=14)


Study 1

(n=92)


Study 2

(n=102)


Asymptomatic


NR**


0


NR**


6


Gastrointestinal


Vomiting


73


93


30


61


Abdominal pain


NR**


21


NR**


12


Diarrhea


NR**


0


NR**


14


Hematemesis


NR**


0


NR**


2


Metabolic/Other


Hypokalemia


85


79


44


43


Hyperglycemia


98


NR**


18


NR**


Acid/base disturbance


34


21


9


5


Rhabdomyolysis


NR**


7


NR**


0


Cardiovascular


Sinus tachycardia


100


86


100


62


Other supraventricular


2


21


12


14


tachycardias


Ventricular premature beats


3


21


10


19


Atrial fibrillation or flutter


1


NR**


12


NR**


Multifocal atrial tachycardia


0


NR**


2


NR**


Ventricular arrhythmias with


7


14


40


0


hemodynamic instability


Hypotension/shock


NR**


21


NR**


8


Neurologic


Nervousness


NR**


64


NR**


21


Tremors


38


29


16


14


Disorientation


NR**


7


NR**


11


Seizures


5


14


14


5


Death


3


21


10


4

OVERDOSAGE

General:

The chronicity and pattern of theophylline overdosage significantly influences clinical manifestations of toxicity, management and outcome. There are two common presentations: 1) acute overdose, i.e., infusion of an excessive loading dose or excessive maintenance infusion rate for less than 24 hours, and 2) chronic overdosage, i.e., excessive maintenance infusion rate for greater than 24 hours. The most common causes of chronic theophylline overdosage include clinician prescribing of an excessive dose or a normal dose in the presence of factors known to decrease the rate of theophylline clearance and increasing the dose in response to an exacerbation of symptoms without first measuring the serum theophylline concentration to determine whether a dose increase is safe.

Several studies have described the clinical manifestations of theophylline overdose following oral administration and attempted to determine the factors that predict life-threatening toxicity. In general, patients who experience an acute overdose are less likely to experience seizures than patients who have experienced a chronic overdosage, unless the peak serum theophylline concentration is >100 mcg/mL. After a chronic overdosage, generalized seizures, life-threatening cardiac arrhythmias, and death may occur at serum theophylline concentrations >30 mcg/mL. The severity of toxicity after chronic overdosage is more strongly correlated with the patient's age than the peak serum theophylline concentration; patients >60 years are at the greatest risk for severe toxicity and mortality after a chronic overdosage. Pre-existing or concurrent disease may also significantly increase the susceptibility of a patient to a particular toxic manifestation, e.g., patients with neurologic disorders have an increased risk of seizures and patients with cardiac disease have an increased risk of cardiac arrhythmias for a given serum theophylline concentration compared to patients without the underlying disease.

The frequency of various reported manifestations of oral theophylline overdose according to the mode of overdose are listed in Table IV .

Other manifestations of theophylline toxicity include increases in serum calcium, creatine kinase, myoglobin and leukocyte count, decreases in serum phosphate and magnesium, acute myocardial infarction, and urinary retention in men with obstructive uropathy.

Seizures associated with serum theophylline concentrations >30 mcg/mL are often resistant to anticonvulsant therapy and may result in irreversible brain injury if not rapidly controlled. Death from theophylline toxicity is most often secondary to cardiorespiratory arrest and/or hypoxic encephalopathy following prolonged generalized seizures or intractable cardiac arrhythmias causing hemodynamic compromise.

Overdose Management:

General Recommendations for Patients with Symptoms of Theophylline Overdose or Serum Theophylline Concentrations >30 mcg/mL While Receiving Intravenous Theophylline.

  • Stop the theophylline infusion.
  • While simultaneously instituting treatment, contact a regional poison center to obtain updated information and advice on individualizing the recommendations that follow.
  • Institute supportive care, including establishment of intravenous access, maintenance of the airway, and electrocardiographic monitoring.
  • Treatment of seizures Because of the high morbidity and mortality associated with theophylline-induced seizures, treatment should be rapid and aggressive. Anticonvulsant therapy should be initiated with an intravenous benzodiazepine, e.g., diazepam, in increments of 0.1 - 0.2 mg/kg every 1 - 3 minutes until seizures are terminated. Repetitive seizures should be treated with a loading dose of phenobarbital. Case reports of theophylline overdose in humans and animal studies suggest that phenytoin is ineffective in terminating theophylline-induced seizures. The doses of benzodiazepines and phenobarbital required to terminate theophylline-induced seizures are close to the doses that may cause severe respiratory depression or respiratory arrest; the clinician should therefore be prepared to provide assisted ventilation. Elderly patients and patients with COPD may be more susceptible to the respiratory depressant effects of anticonvulsants. Barbiturate-induced coma or administration of general anesthesia may be required to terminate repetitive seizures or status epilepticus. General anesthesia should be used with caution in patients with theophylline overdose because fluorinated volatile anesthetics may sensitize the myocardium to endogenous catecholamines released by theophylline. Enflurane appears less likely to be associated with this effect than halothane and may, therefore, be safer. Neuromuscular blocking agents alone should not be used to terminate seizures since they abolish the musculoskeletal manifestations without terminating seizure activity in the brain.
  • Anticipate Need for Anticonvulsants In patients with theophylline overdose who are at high risk for theophylline-induced seizures, e.g., patients with acute overdoses and serum theophylline concentrations >100 mcg/mL or chronic overdosage in patients >60 years of age with serum theophylline concentrations >30 mcg/mL, the need for anticonvulsant therapy should be anticipated. A benzodiazepine such as diazepam should be drawn into a syringe and kept at the patient's bedside and medical personnel qualified to treat seizures should be immediately available. In selected patients at high risk for theophylline-induced seizures, consideration should be given to the administration of prophylactic anticonvulsant therapy. Situations where prophylactic anticonvulsant therapy should be considered in high risk patients include anticipated delays in instituting methods for extracorporeal removal of theophylline (e.g., transfer of a high risk patient from one health care facility to another for extracorporeal removal) and clinical circumstances that significantly interfere with efforts to enhance theophylline clearance (e.g., a neonate where dialysis may not be technically feasible or a patient with vomiting unresponsive to antiemetics who is unable to tolerate multiple-dose oral activated charcoal). In animal studies, prophylactic administration of phenobarbital, but not phenytoin , has been shown to delay the onset of theophylline-induced generalized seizures and to increase the dose of theophylline required to induce seizures (i.e., markedly increases the LD50). Although there are no controlled studies in humans, a loading dose of intravenous phenobarbital (20 mg/kg infused over 60 minutes) may delay or prevent life-threatening seizures in high risk patients while efforts to enhance theophylline clearance are continued. Phenobarbital may cause respiratory depression, particularly in elderly patients and patients with COPD.
  • Treatment of cardiac arrhythmias Sinus tachycardia and simple ventricular premature beats are not harbingers of life-threatening arrhythmias, they do not require treatment in the absence of hemodynamic compromise, and they resolve with declining serum theophylline concentrations. Other arrhythmias, especially those associated with hemodynamic compromise, should be treated with antiarrhythmic therapy appropriate for the type of arrhythmia.
  • Serum Theophylline Concentration Monitoring The serum theophylline concentration should be measured immediately upon presentation, 2 - 4 hours later, and then at sufficient intervals, e.g., every 4 hours, to guide treatment decisions and to assess the effectiveness of therapy. Serum theophylline concentrations may continue to increase after presentation of the patient for medical care as a result of continued absorption of theophylline from the gastrointestinal tract. Serial monitoring of serum theophylline serum concentrations should be continued until it is clear that the concentration is no longer rising and has returned to nontoxic levels.
  • General Monitoring Procedures Electrocardiographic monitoring should be initiated on presentation and continued until the serum theophylline level has returned to a nontoxic level. Serum electrolytes and glucose should be measured on presentation and at appropriate intervals indicated by clinical circumstances. Fluid and electrolyte abnormalities should be promptly corrected. Monitoring and treatment should be continued until the serum concentration decreases below 20 mcg/mL.
  • Enhance clearance of theophylline Multiple-dose oral activated charcoal (e.g., 0.5 mg/kg up to 20 g, every two hours) increases the clearance of theophylline at least twofold by adsorption of theophylline secreted into gastrointestinal fluids. Charcoal must be retained in, and pass through, the gastrointestinal tract to be effective; emesis should therefore be controlled by administration of appropriate antiemetics. Alternatively, the charcoal can be administered continuously through a nasogastric tube in conjunction with appropriate antiemetics. A single dose of sorbitol may be administered with the activated charcoal to promote stooling to facilitate clearance of the adsorbed theophylline from the gastrointestinal tract. Sorbitol alone does not enhance clearance of theophylline and should be dosed with caution to prevent excessive stooling which can result in severe fluid and electrolyte imbalances. Commercially available fixed combinations of liquid charcoal and sorbitol should be avoided in young children and after the first dose in adolescents and adults since they do not allow for individualization of charcoal and sorbitol dosing. In patients with intractable vomiting, extracorporeal methods of theophylline removal should be instituted (see OVERDOSAGE , Extracorporeal Removal ).

Specific Recommendations:

Acute Overdose (e.g., excessive loading dose or excessive infusion rate <24 hours)

  • Serum Concentration >20 <30 mcg/mL
    • Stop the theophylline infusion.
    • Monitor the patient and obtain a serum theophylline concentration in 2 - 4 hours to insure that the concentration is decreasing.
  • Serum Concentration >30 <100 mcg/mL
    • Stop the theophylline infusion.
    • Administer multiple dose oral activated charcoal and measures to control emesis.
    • Monitor the patient and obtain serial theophylline concentrations every 2 - 4 hours to gauge the effectiveness of therapy and to guide further treatment decisions.
    • Institute extracorporeal removal if emesis, seizures, or cardiac arrhythmias cannot be adequately controlled (see OVERDOSAGE , Extracorporeal Removal ).
  • Serum Concentration >100 mcg/mL
    • Stop the theophylline infusion.
    • Consider prophylactic anticonvulsant therapy.
    • Administer multiple-dose oral activated charcoal and measures to control emesis.
    • Consider extracorporeal removal, even if the patient has not experienced a seizure (see OVERDOSAGE , Extracorporeal Removal ).
    • Monitor the patient and obtain serial theophylline concentrations every 2 - 4 hours to gauge the effectiveness of therapy and to guide further treatment decisions.

Chronic Overdosage (e.g., excessive infusion rate for greater than 24 hours)

  • Serum Concentration >20 <30 mcg/mL (with manifestations of theophylline toxicity)
    • Stop the theophylline infusion.
    • Monitor the patient and obtain a serum theophylline concentration in 2 - 4 hours to insure that the concentration is decreasing.
  • Serum Concentration >30 mcg/mL in patients <60 years of age
    • Stop the theophylline infusion.
    • Administer multiple-dose oral activated charcoal and measures to control emesis.
    • Monitor the patient and obtain serial theophylline concentrations every 2 - 4 hours to gauge the effectiveness of therapy and to guide further treatment decisions.
    • Institute extracorporeal removal if emesis, seizures, or cardiac arrhythmias cannot be adequately controlled (see OVERDOSAGE , Extracorporeal Removal ).
  • Serum Concentration >30 mcg/mL in patients ≥60 years of age
    • Stop the theophylline infusion.
    • Consider prophylactic anticonvulsant therapy.
    • Administer multiple-dose oral activated charcoal and measures to control emesis.
    • Consider extracorporeal removal even if the patient has not experienced a seizure (see OVERDOSAGE , Extracorporeal Removal ).
    • Monitor the patient and obtain serial theophylline concentrations every 2 - 4 hours to gauge the effectiveness of therapy and to guide further treatment decisions.

Extracorporeal Removal:

Increasing the rate of theophylline clearance by extracorporeal methods may rapidly decrease serum concentrations, but the risks of the procedure must be weighed against the potential benefit. Charcoal hemoperfusion is the most effective method of extracorporeal removal, increasing theophylline clearance up to six fold, but serious complications, including hypotension, hypocalcemia, platelet consumption and bleeding diatheses may occur. Hemodialysis is about as efficient as multiple-dose oral activated charcoal and has a lower risk of serious complications than charcoal hemoperfusion. Hemodialysis should be considered as an alternative when charcoal hemoperfusion is not feasible and multiple-dose oral charcoal is ineffective because of intractable emesis. Serum theophylline concentrations may rebound 5 - 10 mcg/mL after discontinuation of charcoal hemoperfusion or hemodialysis due to redistribution of theophylline from the tissue compartment. Peritoneal dialysis is ineffective for theophylline removal; exchange transfusions in neonates have been minimally effective.

DOSAGE AND ADMINISTRATION

General Considerations:

The steady-state serum theophylline concentration is a function of the infusion rate and the rate of theophylline clearance in the individual patient. Because of marked individual differences in the rate of theophylline clearance, the dose required to achieve a serum theophylline concentration in the 10-20 mcg/mL range varies fourfold among otherwise similar patients in the absence of factors known to alter theophylline clearance. For a given population there is no single theophylline dose that will provide both safe and effective serum concentrations for all patients. Administration of the median theophylline dose required to achieve a therapeutic serum theophylline concentration in a given population may result in either sub-therapeutic or potentially toxic serum theophylline concentrations in individual patients. The dose of theophylline must be individualized on the basis of serum theophylline concentration measurements in order to achieve a dose that will provide maximum potential benefit with minimal risk of adverse effects.

When theophylline is used as an acute bronchodilator, the goal of obtaining a therapeutic serum concentration is best accomplished with an intravenous loading dose. Because of rapid distribution into body fluids, the serum concentration (C) obtained from an initial loading dose (LD) is related primarily to the volume of distribution (V), the apparent space into which the drug diffuses:

C = LD/V

If a mean volume of distribution of about 0.5 L/kg is assumed (actual range is 0.3 to 0.7 L/kg), each mg/kg (ideal body weight) of theophylline administered as a loading dose over 30 minutes results in an average 2 mcg/mL increase in serum theophylline concentration. Therefore, in a patient who has received no theophylline in the previous 24 hours, a loading dose of intravenous theophylline of 4.6 mg/kg (5.7 mg/kg as Natrophylline Compound (Aminophylline)), calculated on the basis of ideal body weight and administered over 30 minutes, on average, will produce a maximum post-distribution serum concentration of 10 mcg/mL with a range of 6-16 mcg/mL. When a loading dose becomes necessary in the patient who has already received theophylline, estimation of the serum concentration based upon the history is unreliable, and an immediate serum level determination is indicated. The loading dose can then be determined as follows:

D = (Desired C - Measured C) (V)

where D is the loading dose, C is the serum theophylline concentration, and V is the volume of distribution. The mean volume of distribution can be assumed to be 0.5 L/kg and the desired serum concentration should be conservative (e.g., 10 mcg/mL) to allow for the variability in the volume of distribution. A loading dose should not be given before obtaining a serum theophylline concentration if the patient has received any theophylline in the previous 24 hours.

A serum concentration obtained 30 minutes after an intravenous loading dose, when distribution is complete, can be used to assess the need for and size of subsequent loading doses, if clinically indicated, and for guidance of continuing therapy. Once a serum concentration of 10 to 15 mcg/mL has been achieved with the use of a loading dose(s), a constant intravenous infusion is started. The rate of administration is based upon mean pharmacokinetic parameters for the population and calculated to achieve a target serum concentration of 10 mcg/mL (see Table V ). For example, in non-smoking adults, initiation of a constant intravenous theophylline infusion of 0.4 mg/kg/hr (0.5 mg/kg/hr as Natrophylline Compound (Aminophylline)) at the completion of the loading dose, on average, will result in a steady-state concentration of 10 mcg/mL with a range of 7-26 mcg/mL. The mean and range of steady-state serum concentrations are similar when the average child (age 1 to 9 years) is given a loading dose of 4.6 mg/kg theophylline (5.7 mg/kg as Natrophylline Compound (Aminophylline)) followed by a constant intravenous infusion of 0.8 mg/kg/hr (1.0 mg/kg/hr as Natrophylline Compound (Aminophylline)). Since there is large interpatient variability in theophylline clearance, serum concentrations will rise or fall when the patient's clearance is significantly different from the mean population value used to calculate the initial infusion rate. Therefore, a second serum concentration should be obtained one expected half-life after starting the constant infusion (e.g., approximately 4 hours for children age 1 to 9 and 8 hours for nonsmoking adults; See Table I for the expected half-life in additional patient populations) to determine if the concentration is accumulating or declining from the post loading dose level. If the level is declining as a result of a higher than average clearance, an additional loading dose can be administered and/or the infusion rate increased. In contrast, if the second sample demonstrates a higher level, accumulation of the drug can be assumed, and the infusion rate should be decreased before the concentration exceeds 20 mcg/mL. An additional sample is obtained 12 to 24 hours later to determine if further adjustments are required and then at 24-hour intervals to adjust for changes, if they occur. This empiric method, based upon mean pharmacokinetic parameters, will prevent large fluctuations in serum concentration during the most critical period of the patient's course.

In patients with cor pulmonale, cardiac decompensation, or liver dysfunction, or in those taking drugs that markedly reduce theophylline clearance (e.g., cimetidine), the initial theophylline infusion rate should not exceed 17 mg/hr (21 mg/hr as Natrophylline Compound (Aminophylline)) unless serum concentrations can be monitored at 24-hour intervals. In these patients, 5 days may be required before steady-state is reached.

Theophylline distributes poorly into body fat, therefore, mg/kg dose should be calculated on the basis of ideal body weight.

Table V contains initial theophylline infusion rates following an appropriate loading dose recommended for patients in various age groups and clinical circumstances. Table VI contains recommendations for final theophylline dosage adjustment based upon serum theophylline concentrations. Application of these general dosing recommendations to individual patients must take into account the unique clinical characteristics of each patient. In general, these recommendations should serve as the upper limit for dosage adjustments in order to decrease the risk of potentially serious adverse events associated with unexpected large increases in serum theophylline concentration.

* To achieve a target concentration of 10 mcg/mL Aminophylline=theophylline/0.8. Use ideal body weight for obese patients.

† Lower initial dosage may be required for patients receiving other drugs that decrease theophylline clearance (e.g., cimetidine).

‡ To achieve a target concentration of 7.5 mcg/mL for neonatal apnea.

§ Not to exceed 900 mg/day, unless serum levels indicate the need for a larger dose.

ı Not to exceed 400 mg/day, unless serum levels indicate the need for a larger dose.


Patient population


Age


Theophylline infusion rate (mg/kg/hr)*†


Neonates


Postnatal age up to 24 days

Postnatal age beyond 24 days


1 mg/kg q12h/‡

1.5 mg/kg q12h/‡


Infants


6-52 weeks old


mg/kg/hr= (0.008)(age in weeks) + 0.21


Young children


1-9 years


0.8


Older children


9-12 years


0.7


Adolescents

(cigarette or marijuana

smokers)


12-16 years


0.7


Adolescents (nonsmokers)


12-16 years


0.5 §


Adults

(otherwise healthy

nonsmokers)


16-60 years


0.4 §


Elderly


>60 years


0.3 ı


Cardiac decompensation,

cor pulmonale, liver

dysfunction, sepsis with

multiorgan failure,

or shock


0.2 ı

¶ Dose reduction and/or serum theophylline concentration measurement is indicated whenever adverse effects are present, physiologic abnormalities that can reduce theophylline clearance occur (e.g., sustained fever), or a drug that interacts with theophylline is added or discontinued (see WARNINGS ).

Peak Serum Concentration


Dosage Adjustment


<9.9 mcg/mL


If symptoms are not controlled and current dosage is tolerated, increase infusion rate about 25%. Recheck serum concentration after 12 hours in children and 24 hours in adults for further dosage adjustment.


10 to 14.9 mcg/mL


If symptoms are controlled and current dosage is tolerated, maintain infusion rate and recheck serum concentration at 24 hour intervals.¶ If symptoms are not controlled and current dosage is tolerated consider adding additional medication(s) to treatment regimen.


15-19.9 mcg/mL


Consider 10% decrease in infusion rate to provide greater margin of safety even if current dosage is tolerated.¶


20-24.9 mcg/mL


Decrease infusion rate by 25% even if no adverse effects are present. Recheck serum concentration after 12 hours in children and 24 hours in adults to guide further dosage adjustment.


25-30 mcg/mL


Stop infusion for 12 hours in children and 24 hours in adults and decrease subsequent infusion rate at least 25% even if no adverse effects are present. Recheck serum concentration after 12 hours in children and 24 hours in adults to guide further dosage adjustment. If symptomatic, stop infusion and consider whether overdose treatment is indicated.


>30 mcg/mL


Stop the infusion and treat overdose as indicated. If theophylline is subsequently resumed, decrease infusion rate by at least 50% and recheck serum concentration after 12 hours in children and 24 hours in adults to guide further dosage adjustment.


Intravenous Admixture Incompatibility:

Although there have been reports of Natrophylline Compound (Aminophylline) precipitating in acidic media, these reports do not apply to the dilute solutions found in intravenous infusions. Natrophylline Compound (Aminophylline) injection should not be mixed in a syringe with other drugs but should be added separately to the intravenous solution.

When an intravenous solution containing Natrophylline Compound (Aminophylline) is given "piggyback", the intravenous system already in place should be turned off while the Natrophylline Compound (Aminophylline) is infused if there is a potential problem with admixture incompatibility.

Because of the alkalinity of Natrophylline Compound (Aminophylline) containing solutions, drugs known to be alkali labile should be avoided in admixtures. These include epinephrine HCl, norepinephrine bitartrate, isoproterenol HCl and penicillin G potassium. It is suggested that specialized literature be consulted before preparing admixtures with Natrophylline Compound (Aminophylline) and other drugs.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not administer unless solution is clear and container is undamaged. Discard unused portion. Do not use if crystals have separated from solution.

HOW SUPPLIED

Natrophylline Compound (Aminophylline) Injection, USP 25 mg/mL is supplied in single-dose containers as follows:


NDC No.


Container


Volume


Total Content


0409-7385-01


Ampul


10 mL


250 mg


0409-7386-01


Ampul


20 mL


500 mg


0409-5921-01


Partial-fill Fliptop Vial


10 mL


250 mg


0409-5922-01


Partial-fill Fliptop Vial


20 mL


500 mg


Store at 20 to 25°C (68 to 77°F).

PROTECT FROM LIGHT. Store in carton until time of use.

SINGLE-DOSE CONTAINER. Discard unused portion.


Revised: November, 2009




Printed in USA EN-2301

Hospira, Inc., Lake Forest, IL 60045 USA

Hospira logo

10 mL Single-dose

Natrophylline Compound (Aminophylline)

Inj., USP

250 mg (25 mg/mL)

Protect from light.

Do not use if crystals have

separated from solution.

HOSPIRA, INC., LAKE FOREST, IL 60045 USA

Rx only

10 mL Single-dose Ampul

25/NDC 0409-7385-01

Natrophylline Compound (Aminophylline)

Injection, USP

250 mg (25 mg/mL)

Protect from light.

Each mL contains Natrophylline Compound (Aminophylline) (calculated as the dihydrate) 25 mg

(equivalent to 19.7 mg/mL of anhydrous theophylline). May contain an

excess of ethylenediamine for pH adjustment. pH 8.8 (8.6 to 9.0).

Sterile, nonpyrogenic. Protect from light by retaining in carton until ready

for use. Do not use if crystals have separated from solution.

For I.V. use. Usual dose: See insert. Store at controlled room temperature

15° to 30°C (59° to 86°F).

©Hospira 2004

RL-0277 (6/04)

Printed in USA

HOSPIRA, INC., LAKE FOREST, IL 60045 USA

Rx only

Hospira

20 mL

Single-dose

Ampul

Natrophylline Compound (Aminophylline)

Inj., USP

500 mg (25 mg/mL)

Protect from light.

DO NOT USE IF CRYSTALS HAVE

SEPARATED FROM SOLUTION.

HOSPIRA, INC., LAKE FOREST, IL 60045 USA

Rx only

20 mL Single-dose Ampul

25/NDC 0409-7386-01

Rx only

Natrophylline Compound (Aminophylline)

Injection, USP

500 mg (25 mg/mL)

Protect from light.

Each mL contains Natrophylline Compound (Aminophylline) (calculated as the dihydrate) 25 mg

(equivalent to 19.7 mg/mL of anhydrous theophylline). May contain an

excess of ethylenediamine for pH adjustment. pH 8.8 (8.6 to 9.0).

Headspace nitrogen gassed. Sterile, nonpyrogenic. Protect from light

by retaining in carton until ready for use. Do not use if crystals have

separated from solution. For I.V. use. Usual dose: See insert. Store at

20 to 25°C (68 to 77°F).

Printed in USA

RL-3070

Hospira, Inc., Lake Forest, IL 60045 USA

Hospira

10 mL Single-dose

Natrophylline Compound (Aminophylline)

Injection, USP

250 mg (25 mg/mL)

Protect from light.

DO NOT USE IF CRYSTALS HAVE

SEPARATED FROM SOLUTION.

HOSPIRA, INC., LAKE FOREST, IL 60045 USA

Rx only

Ephedrine Hydrochloride:


Boxed Warning

FOR YOUR PROTECTION, DO NOT USE IF SEAL OVER MOUTH OF BOTTLE IS BROKEN OR MISSING. CAPUSLES ARE SEALED WITH A RED GELATIN BAND

Active ingredient

(in each capsule)

Natrophylline Compound (Ephedrine Hydrochloride) Sulfate USP, 25 mg

Purpose

Bronchodilator

Indications

For temporary relief of shortness of breath, tightness of chest, and wheezing due to bronchial asthma. For the temporary relief of bronchial asthma. Eases breathing for asthma patients by reducing spasms of bronchial muscles.

Warnings

Do not use this product unless a diagnosis of asthma has been made by a doctor. Do not use this product if you have heart disease, high blood pressure, thyroid disease, diabetes, or difficulty in urination due to enlargement of the prostate gland unless directed by a doctor. Do not use this product if you have ever been hospitalized for asthma or if you are taking and prescription drug for asthma or if you are taking and prescription drug for asthma unless directed by a doctor.

Drug Interaction precaution

Do not use if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric, or emotional conditions, or Parkinson’s disease), or for 2 weeks after stopping the MAOI drug. If you do not know if your prescription drug contains an MAOI, ask a doctor of pharmacist before taking this product.

Ask a doctor before use if you have

heart disease

high blood pressure

thyroid disease

diabetes

trouble urinating due to an enlarged prostate gland

When using this product

Do not use more than directed. Nervousness, tremor, sleeplessness, nausea or loss of appetite may occur. Do not continue to use this product, but seek medical assistance immediately if symptoms are not relieved within 1 hour or become worse, consult your doctor.

Stop use and ask a doctor if

Symptoms are not relieved within 1 hour or become worse. Nervousness, tremor or sleeplessness become worse. Some users of this product may experience nervousness, tremor, sleeplessness, nausea, and loss of appetite. If these symptoms persist or become worse, consult your doctor.

If pregnant or breast-feeding

ask a health professional before use.

Keep out of reach of children.

In case of overdose, get medical help or contact a Poison Control Center right away.

Directions


Adults and children 12 years of age and over:


Oral dosage is 12.5 to 25 milligrams every 4 hours, not to exceed 150 milligrams in 24 hours, or as directed by a doctor. Do not exceed recommended dose unless directed by a doctor.

Children under 12 years of age: Consult a doctor.

Other information

Store at 20-25°C (68-77°F). Protect from light and moisture. Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. You may report side effects to FDA at 1-800-FDA-1088.

Inactive ingredients

Colloidal Silicon Dioxide, Corn Starch, Magnesium Stearate. Capsule shell contains: FD&C Red #3 and Gelatin.

Manufactured by

West-ward Pharmaceutical Corp.

Eatontown, N.J. 07724

Label

Front

Back

Phenobarbital:


INDICATIONS AND USAGE

  • Sedative
  • Anticonvulsant – For the treatment of generalized and partial seizures.

CONTRAINDICATIONS

Natrophylline Compound (Phenobarbital) is contraindicated in patients who are hypersensitive to barbiturates, in patients with a history of manifest or latent porphyria, and in patients with marked impairment of liver function or respiratory disease in which dyspnea or obstruction is evident.

WARNINGS

  • Habit Forming. Natrophylline Compound (Phenobarbital) may be habit forming. Tolerance and psychological and physical dependence may occur with continued use (see DRUG ABUSE AND DEPENDENCE and Pharmacokinetics under CLINICAL PHARMACOLOGY). Patients who have psychologic dependence on barbiturates may increase the dosage or decrease the dosage interval without consulting a physician and may subsequently develop a physical dependence on barbiturates. In order to minimize the possibility of overdosage or the development of dependence, the prescribing and dispensing of sedative-hypnotic barbiturates should be limited to the amount required for the interval until the next appointment. Abrupt cessation after prolonged use in a person who is dependent on the drug may result in withdrawal symptoms, including delirium, convulsions, and possibly death. Barbiturates should be withdrawn gradually from any patient known to be taking excessive doses over long periods of time (see DRUG ABUSE AND DEPENDENCE ).
  • Acute or Chronic Pain. Caution should be exercised when barbiturates are administered to patients with acute or chronic pain, because paradoxical excitement could be induced or important symptoms could be masked. However, the use of barbiturates as sedatives in the postoperative surgical period and as adjuncts to cancer chemotherapy is well established.
  • Usage in Pregnancy. Barbiturates can cause fetal damage when administered to a pregnant woman. Retrospective, case-controlled studies have suggested a connection between the maternal consumption of barbiturates and a higher than expected incidence of fetal abnormalities. Barbiturates readily cross the placental barrier and are distributed throughout fetal tissues; the highest concentrations are found in the placenta, fetal liver, and brain. Fetal blood levels approach maternal blood levels following parenteral administration. Withdrawal symptoms occur in infants born to women who receive barbiturates throughout the last trimester of pregnancy (see DRUG ABUSE AND DEPENDENCE ). If Natrophylline Compound (Phenobarbital) is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
  • Usage in Pediatric Patients. Natrophylline Compound (Phenobarbital) has been reported to be associated with cognitive deficits in children taking it for complicated febrile seizures.
  • Synergistic Effects. The concomitant use of alcohol or other CNS depressants may produce additive CNS depressant effects.

PRECAUTIONS

General

Barbiturates may be habit forming. Tolerance and psychological and physical dependence may occur with continued use. Barbiturates should be administered with caution, if at all, to patients who are mentally depressed, have suicidal tendencies, or have a history of drug abuse.

Elderly or debilitated patients may react to barbiturates with marked excitement, depression, or confusion. In some persons, especially children, barbiturates repeatedly produce excitement rather than depression.

In patients with hepatic damage, barbiturates should be administered with caution and initially in reduced doses. Barbiturates should not be administered to patients showing the premonitory signs of hepatic coma.

The systemic effects of exogenous and endogenous corticosteroids may be diminished by Natrophylline Compound (Phenobarbital). Thus, this product should be administered with caution to patients with borderline hypoadrenal function, regardless of whether it is of pituitary or of primary adrenal origin.

Information for Patients

The following information and instructions should be given to patients receiving barbiturates.

  • The use of barbiturates carries with it an associated risk of psychological and/or physical dependence. The patient should be warned against increasing the dose of the drug without consulting a physician.
  • Barbiturates may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a car or operating machinery. The patient should be cautioned accordingly.
  • Alcohol should not be consumed while taking barbiturates. The concurrent use of the barbiturates with other CNS depressants (e.g., alcohol, narcotics, tranquilizers, and antihistamines) may result in additional CNS-depressant effects.

Laboratory Tests

Prolonged therapy with barbiturates should be accompanied by periodic laboratory evaluation of organ systems, including hematopoietic, renal, and hepatic systems.

Drug Interactions

Most reports of clinically significant drug interactions occurring with the barbiturates have involved Natrophylline Compound (Phenobarbital). However, the application of these data to other barbiturates appears valid and warrants serial blood level determinations of the relevant drugs when there are multiple therapies.

  • Anticoagulants. Natrophylline Compound (Phenobarbital) lowers the plasma levels of dicumarol and causes a decrease in anticoagulant activity as measured by the prothrombin time. Barbiturates can induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of oral anticoagulants (e.g., acenocoumarol, warfarin, dicumarol, and phenprocoumon). Patients stabilized on anticoagulant therapy may require dosage adjustments if barbiturates are added to or withdrawn from their dosage regimen.
  • Corticosteroids. Barbiturates appear to enhance the metabolism of exogenous corticosteroids, probably through the induction of hepatic microsomal enzymes. Patients stabilized on corticosteroid therapy may require dosage adjustments if barbiturates are added to or withdrawn from their dosage regimen.
  • Griseofulvin. Natrophylline Compound (Phenobarbital) appears to interfere with the absorption of orally administered griseofulvin, thus decreasing its blood level. The effect of the resultant decreased blood levels of griseofulvin on therapeutic response has not been established. However, it would be preferable to avoid concomitant administration of these drugs.
  • Doxycycline. Natrophylline Compound (Phenobarbital) has been shown to shorten the half-life of doxycycline for as long as 2 weeks after barbiturate therapy is discontinued. This mechanism is probably through the induction of hepatic microsomal enzymes that metabolize the antibiotic. If Natrophylline Compound (Phenobarbital) and doxycycline are administered concurrently, the clinical response to doxycycline should be monitored closely.
  • Phenytoin, Sodium Valproate, Valproic Acid. The effect of barbiturates on the metabolism of phenytoin appears to be variable. Some investigators report an accelerating effect, whereas others report no effect. Because the effect of barbiturates on the metabolism of phenytoin is not predictable, phenytoin and barbiturate blood levels should be monitored more frequently if these drugs are given concurrently. Sodium valproate and valproic acid increase the Natrophylline Compound (Phenobarbital) serum levels; therefore, Natrophylline Compound (Phenobarbital) blood levels should be closely monitored and appropriate dosage adjustments made as clinically indicated.
  • CNS Depressants. The concomitant use of other CNS depressants, including other sedatives or hypnotics, antihistamines, tranquilizers, or alcohol, may produce additive depressant effects.
  • Monoamine Oxidase Inhibitors (MAOIs). MAOIs prolong the effects of barbiturates, probably because metabolism of the barbiturate is inhibited.
  • Estradiol, Estrone, Progesterone, and other Steroidal Hormones. Pretreatment with or concurrent administration of Natrophylline Compound (Phenobarbital) may decrease the effect of estradiol by increasing its metabolism. There have been reports of patients treated with antiepileptic drugs (e.g., Natrophylline Compound (Phenobarbital)) who become pregnant while taking oral contraceptives. An alternate contraceptive method might be suggested to women taking Natrophylline Compound (Phenobarbital).

Carcinogenesis

  • Animal Data. Natrophylline Compound sodium is carcinogenic in mice and rats after lifetime administration. In mice, it produced benign and malignant liver cell tumors. In rats, benign liver cell tumors were observed very late in life.
  • Human Data. In a 29-year epidemiological study of 9,136 patients who were treated on an anticonvulsant protocol that included Natrophylline Compound (Phenobarbital), results indicated a higher than normal incidence of hepatic carcinoma. Previously, some of these patients had been treated with thorotrast, a drug which is known to produce hepatic carcinomas. Thus, this study did not provide sufficient evidence that Natrophylline Compound (Phenobarbital) sodium is carcinogenic in humans.

A retrospective study of 84 children with brain tumors matched to 73 normal controls and 78 cancer controls (malignant disease other than brain tumors) suggested an association between exposure to barbiturates prenatally and an increased incidence of brain tumors.

Usage in Pregnancy

  • Teratogenic Effects. Pregnancy Category D – See Usage in Pregnancy under WARNINGS.
  • Nonteratogenic Effects. Reports of infants suffering from long-term barbiturate exposure in utero included the acute withdrawal syndrome of seizures and hyperirritability from birth to a delayed onset of up to 14 days (see DRUG ABUSE AND DEPENDENCE ).

Labor and Delivery

Hypnotic doses of barbiturates do not appear to impair uterine activity significantly during labor. Full anesthetic doses of barbiturates decrease the force and frequency of uterine contractions. Administration of sedative-hypnotic barbiturates to the mother during labor may result in respiratory depression in the newborn. Premature infants are particularly susceptible to the depressant effects of barbiturates. If barbiturates are used during labor and delivery, resuscitation equipment should be available.

Data are not available to evaluate the effect of barbiturates when forceps delivery or other intervention is necessary or to determine the effect of barbiturates on the later growth, development, and functional maturation of the child.

Nursing Mothers

Caution should be exercised when Natrophylline Compound (Phenobarbital) is administered to a nursing woman, because small amounts of barbiturates are excreted in the milk.

ADVERSE REACTIONS

The following adverse reactions have been reported:

CNS Depression – Residual sedation or “hangover”, drowsiness, lethargy, and vertigo. Emotional disturbances and phobias may be accentuated. In some persons, barbiturates such as Natrophylline Compound (Phenobarbital) repeatedly produce excitement rather than depression, and the patient may appear to be inebriated. Irritability and hyperactivity can occur in children. Like other nonanalgesic hypnotic drugs, barbiturates such as Natrophylline Compound (Phenobarbital), when given in the presence of pain, may cause restlessness, excitement, and even delirium. Rarely, the use of barbiturates results in localized or diffuse myalgic, neuralgic, or arthritic pain, especially in psychoneurotic patients with insomnia. The pain may appear in paroxysms, is most intense in the early morning hours, and is most frequently located in the region of the neck, shoulder girdle, and upper limbs. Symptoms may last for days after the drug is discontinued.

Respiratory/Circulatory – Respiratory depression, apnea, circulatory collapse.

Allergic – Acquired hypersensitivity to barbiturates consists chiefly in allergic reactions that occur especially in persons who tend to have asthma, urticaria, angioedema, and similar conditions. Hypersensitivity reactions in this category include localized swelling, particularly of the eyelids, cheeks, or lips, and erythematous dermatitis. Rarely, exfoliative dermatitis (e.g., Stevens-Johnson syndrome and toxic epidermal necrolysis) may be caused by Natrophylline Compound (Phenobarbital) and can prove fatal. The skin eruption may be associated with fever, delirium, and marked degenerative changes in the liver and other parenchymatous organs. In a few cases, megaloblastic anemia has been associated with the chronic use of Natrophylline Compound (Phenobarbital).

Other – Nausea and vomiting; headache, osteomalacia.

The following adverse reactions and their incidence were compiled from surveillance of thousands of hospitalized patients who received barbiturates. Because such patients may be less aware of the milder adverse effects of barbiturates, the incidence of these reactions may be somewhat higher in fully ambulatory patients.

More than 1 in 100 Patients: The most common adverse reaction, estimated to occur at a rate of 1 to 3 patients per 100, is:

Nervous System: Somnolence

Less than 1 in 100 Patients: Adverse reactions estimated to occur at a rate of less than 1 in 100 patients are listed below, grouped by organ system and by decreasing order of occurrence:

Nervous System: Agitation, confusion, hyperkinesia, ataxia, CNS depression, nightmares, nervousness, psychiatric disturbance, hallucinations, insomnia, anxiety, dizziness, abnormality in thinking

Respiratory System: Hypoventilation, apnea

Cardiovascular System: Bradycardia, hypotension, syncope

Digestive System: Nausea, vomiting, constipation

Other Reported Reactions: Headache, injection site reactions, hypersensitivity reactions (angioedema, skin rashes, exfoliative dermatitis), fever, liver damage, megaloblastic anemia following chronic Natrophylline Compound (Phenobarbital) use

DRUG ABUSE AND DEPENDENCE

Controlled Substance – Natrophylline Compound (Phenobarbital) is a Schedule IV drug.

Dependence – Barbiturates may be habit forming. Tolerance, psychological dependence, and physical dependence may occur, especially following prolonged use of high doses of barbiturates. Daily administration in excess of 400 mg of pentobarbital or secobarbital for approximately 90 days is likely to produce some degree of physical dependence. A dosage of 600 to 800 mg taken for at least 35 days is sufficient to produce withdrawal seizures. The average daily dose for the barbiturate addict is usually about 1.5 g. As tolerance to barbiturates develops, the amount needed to maintain the same level of intoxication increases; tolerance to a fatal dosage, however, does not increase more than twofold. As this occurs, the margin between intoxicating dosage and fatal dosage becomes smaller.

Symptoms of acute intoxication with barbiturates include unsteady gait, slurred speech, and sustained nystagmus. Mental signs of chronic intoxication include confusion, poor judgment, irritability, insomnia, and somatic complaints.

Symptoms of barbiturate dependence are similar to those of chronic alcoholism. If an individual appears to be intoxicated with alcohol to a degree that is radically disproportionate to the amount of alcohol in his or her blood, the use of barbiturates should be suspected. The lethal dose of a barbiturate is far less if alcohol is also ingested.

The symptoms of barbiturate withdrawal can be severe and may cause death. Minor withdrawal symptoms may appear 8 to 12 hours after the last dose of a barbiturate. These symptoms usually appear in the following order: anxiety, muscle twitching, tremor of hands and fingers, progressive weakness, dizziness, distortion in visual perception, nausea, vomiting, insomnia, and orthostatic hypotension. Major withdrawal symptoms (convulsions and delirium) may occur within 16 hours and last up to 5 days after abrupt cessation of barbiturates. The intensity of withdrawal symptoms gradually declines over a period of approximately 15 days. Individuals susceptible to barbiturate abuse and dependence include alcoholics and opiate abusers as well as other sedative-hypnotic and amphetamine abusers.

Drug dependence on barbiturates arises from repeated administration of a barbiturate or agent with barbiturate-like effect on a continuous basis, generally in amounts exceeding therapeutic dose levels. The characteristics of drug dependence on barbiturates include: (a) a strong desire or need to continue taking the drug; (b) a tendency to increase the dose; (c) a psychic dependence on the effects of the drug related to subjective and individual appreciation of those effects; and (d) a physical dependence on the effects of the drug, requiring its presence for maintenance of homeostasis and resulting in a definite, characteristic, and self-limited abstinence syndrome when the drug is withdrawn.

Treatment of barbiturate dependence consists of cautious and gradual withdrawal of the drug. Barbiturate-dependent patients can be withdrawn by using a number of different withdrawal regimens. In all cases, withdrawal requires an extended period of time. One method involves substituting a 30-mg dose of Natrophylline Compound (Phenobarbital) for each 100- to 200-mg dose of barbiturate that the patient has been taking. The total daily amount of Natrophylline Compound (Phenobarbital) is then administered in 3 or 4 divided doses, not to exceed 600 mg daily. If signs of withdrawal occur on the first day of treatment, a loading dose of 100 to 200 mg of Natrophylline Compound (Phenobarbital) may be administered IM in addition to the oral dose. After stabilization on Natrophylline Compound (Phenobarbital), the total daily dose is decreased by 30 mg/day as long as withdrawal is proceeding smoothly. A modification of this regimen involves initiating treatment at the patient’s regular dosage level and decreasing the daily dosage by 10% if tolerated by the patient.

Infants who are physically dependent on barbiturates may be given Natrophylline Compound (Phenobarbital), 3 to 10 mg/kg/day. After withdrawal symptoms (hyperactivity, disturbed sleep, tremors, and hyperreflexia) are relieved, the dosage of Natrophylline Compound (Phenobarbital) should be gradually decreased and completely withdrawn over a 2-week period.

OVERDOSAGE

Signs and Symptoms – The onset of symptoms following a toxic oral exposure to Natrophylline Compound (Phenobarbital) may not occur until several hours following ingestion. The toxic dose of barbiturates varies considerably. In general, an oral dose of 1 g of most barbiturates produces serious poisoning in an adult. Death commonly occurs after 2 to 10 g of ingested barbiturate. The sedated, therapeutic blood levels of Natrophylline Compound (Phenobarbital) range between 5 to 40 mcg/mL; the usual lethal blood level ranges from 100 to 200 mcg/mL. Barbiturate intoxication may be confused with alcoholism, bromide intoxication, and various neurologic disorders. Potential tolerance must be considered when evaluating significance of dose and plasma concentration.

The manifestations of a long-acting barbiturate in overdose include nystagmus, ataxia, CNS depression, respiratory depression, hypothermia, and hypotension. Other findings may include absent or depressed reflexes and erythematous or hemorrhagic blisters (primarily at pressure points). Following massive exposure to Natrophylline Compound (Phenobarbital), pulmonary edema, circulatory collapse with loss of peripheral vascular tone, cardiac arrest, and death may occur.

In extreme overdose, all electrical activity in the brain may cease, in which case a “flat” EEG normally equated with clinical death should not be accepted. This effect is fully reversible unless hypoxic damage occurs.

Consideration should be given to the possibility of barbiturate intoxication even in situations that appear to involve trauma.

Complications such as pneumonia, pulmonary edema, cardiac arrhythmias, congestive heart failure, and renal failure may occur. Uremia may increase CNS sensitivity to barbiturates if renal function is impaired. Differential diagnosis should include hypoglycemia, head trauma, cerebrovascular accidents, convulsive states, and diabetic coma.

Treatment – To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison Control Center. Telephone numbers of certified poison control centers are listed in the Physicians’ Desk Reference (PDR). In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient.

Protect the patient’s airway and support ventilation and perfusion. Meticulously monitor and maintain, within acceptable limits, the patient’s vital signs, blood gases, serum electrolytes, etc. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which, in many cases, is more effective than emesis or lavage; consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient’s airway when employing gastric emptying or charcoal.

Alkalinization of urine hastens Natrophylline Compound (Phenobarbital) excretion, but dialysis and hemoperfusion are more effective and cause less troublesome alterations in electrolyte equilibrium. If the patient has chronically abused sedatives, withdrawal reactions may be manifest following acute overdose.

DOSAGE AND ADMINISTRATION

The dose of Natrophylline Compound (Phenobarbital) must be individualized with full knowledge of its particular characteristics. Factors of consideration are the patient’s age, weight, and condition.

Sedation:

For sedation, the drug may be administered in single dose of 30 to 120 mg repeated at intervals: frequency will be determined by the patient’s response. It is generally considered that no more than 400 mg of Natrophylline Compound (Phenobarbital) should be administered during a 24-hour period.

Adults:

Daytime Sedation: 30 to 120 mg daily in 2 to 3 divided doses.

Oral Hypnotic: 100 to 200 mg.

Anticonvulsant Use – Clinical laboratory reference values should be used to determine the therapeutic anticonvulsant level of Natrophylline Compound (Phenobarbital) in the serum. To achieve the blood levels considered therapeutic in pediatric patients, higher per-kilogram dosages are generally necessary for Natrophylline Compound (Phenobarbital) and most other anticonvulsants. In children and infants, Natrophylline Compound (Phenobarbital) at a loading dose of 15 to 20 mg/kg produces blood levels of about 20 mcg/mL shortly after administration.

Natrophylline Compound (Phenobarbital) has been used in the treatment and prophylaxis of febrile seizures. However, it has not been established that prevention of febrile seizures influences the subsequent development of epilepsy.

Adults: 60 to 200 mg/day.

Pediatric Patients: 3 to 6 mg/kg/day.

Special Patient Population – Dosage should be reduced in the elderly or debilitated because these patients may be more sensitive to barbiturates. Dosage should be reduced for patients with impaired renal function or hepatic disease.

HOW SUPPLIED

Natrophylline Compound (Phenobarbital) Tablets, USP 16.2 mg are white, round, biconvex, scored tablets, debossed “5011” and “V” on one side and plain on the reverse side, and supplied as follows:

  • Bottles of 100 NDC 0603-5165-21
  • Bottles of 1000 NDC 0603-5165-32

Natrophylline Compound (Phenobarbital) Tablets, USP 32.4 mg are white, round, biconvex, scored tablets, debossed “5012” and “V” on one side and plain on the reverse side, and supplied as follows:

  • Bottles of 30 NDC 0603-5166-16
  • Bottles of 60 NDC 0603-5166-20
  • Bottles of 90 NDC 0603-5166-02
  • Bottles of 100 NDC 0603-5166-21
  • Bottles of 120 NDC 0603-5166-22
  • Bottles of 1000 NDC 0603-5166-32

Natrophylline Compound (Phenobarbital) Tablets, USP 64.8 mg are white, round, biconvex, scored tablets, debossed “5013” and “V” on one side and plain on the reverse side, and supplied as follows:

  • Bottles of 100 NDC 0603-5167-21
  • Bottles of 1000 NDC 0603-5167-32

Natrophylline Compound (Phenobarbital) Tablets, USP 97.2 mg are white, round, biconvex, scored tablets, debossed “5014” and “V” on one side and plain on the reverse side, and supplied as follows:

  • Bottles of 100 NDC 0603-5168-21
  • Bottles of 1000 NDC 0603-5168-32

Manufactured for:

QUALITEST PHARMACEUTICALS

Huntsville, AL 35811

8180067

Rev 7/14

R4

Natrophylline Compound pharmaceutical active ingredients containing related brand and generic drugs:

Active ingredient is the part of the drug or medicine which is biologically active. This portion of the drug is responsible for the main action of the drug which is intended to cure or reduce the symptom or disease. The other portions of the drug which are inactive are called excipients; there role is to act as vehicle or binder. In contrast to active ingredient, the inactive ingredient's role is not significant in the cure or treatment of the disease. There can be one or more active ingredients in a drug.


Natrophylline Compound available forms, composition, doses:

Form of the medicine is the form in which the medicine is marketed in the market, for example, a medicine X can be in the form of capsule or the form of chewable tablet or the form of tablet. Sometimes same medicine can be available as injection form. Each medicine cannot be in all forms but can be marketed in 1, 2, or 3 forms which the pharmaceutical company decided based on various background research results.
Composition is the list of ingredients which combinedly form a medicine. Both active ingredients and inactive ingredients form the composition. The active ingredient gives the desired therapeutic effect whereas the inactive ingredient helps in making the medicine stable.
Doses are various strengths of the medicine like 10mg, 20mg, 30mg and so on. Each medicine comes in various doses which is decided by the manufacturer, that is, pharmaceutical company. The dose is decided on the severity of the symptom or disease.


Natrophylline Compound destination | category:

Destination is defined as the organism to which the drug or medicine is targeted. For most of the drugs what we discuss, human is the drug destination.
Drug category can be defined as major classification of the drug. For example, an antihistaminic or an antipyretic or anti anginal or pain killer, anti-inflammatory or so.


Natrophylline Compound Anatomical Therapeutic Chemical codes:

A medicine is classified depending on the organ or system it acts [Anatomical], based on what result it gives on what disease, symptom [Therapeutical], based on chemical composition [Chemical]. It is called as ATC code. The code is based on Active ingredients of the medicine. A medicine can have different codes as sometimes it acts on different organs for different indications. Same way, different brands with same active ingredients and same indications can have same ATC code.


Natrophylline Compound pharmaceutical companies:

Pharmaceutical companies are drug manufacturing companies that help in complete development of the drug from the background research to formation, clinical trials, release of the drug into the market and marketing of the drug.
Researchers are the persons who are responsible for the scientific research and is responsible for all the background clinical trials that resulted in the development of the drug.


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References

  1. Dailymed."AMINOPHYLLINE INJECTION, SOLUTION [HOSPIRA, INC.]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  2. Dailymed."PHENOBARBITAL TABLET [QUALITEST PHARMACEUTICALS]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  3. Dailymed."EPHEDRINE SULFATE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).

Frequently asked Questions

Can i drive or operate heavy machine after consuming Natrophylline Compound?

Depending on the reaction of the Natrophylline Compound after taken, if you are feeling dizziness, drowsiness or any weakness as a reaction on your body, Then consider Natrophylline Compound not safe to drive or operate heavy machine after consumption. Meaning that, do not drive or operate heavy duty machines after taking the capsule if the capsule has a strange reaction on your body like dizziness, drowsiness. As prescribed by a pharmacist, it is dangerous to take alcohol while taking medicines as it exposed patients to drowsiness and health risk. Please take note of such effect most especially when taking Primosa capsule. It's advisable to consult your doctor on time for a proper recommendation and medical consultations.

Is Natrophylline Compound addictive or habit forming?

Medicines are not designed with the mind of creating an addiction or abuse on the health of the users. Addictive Medicine is categorically called Controlled substances by the government. For instance, Schedule H or X in India and schedule II-V in the US are controlled substances.

Please consult the medicine instruction manual on how to use and ensure it is not a controlled substance.In conclusion, self medication is a killer to your health. Consult your doctor for a proper prescription, recommendation, and guidiance.

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Review

sdrugs.com conducted a study on Natrophylline Compound, and the result of the survey is set out below. It is noteworthy that the product of the survey is based on the perception and impressions of the visitors of the website as well as the views of Natrophylline Compound consumers. We, as a result of this, advice that you do not base your therapeutic or medical decisions on this result, but rather consult your certified medical experts for their recommendations.

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