De Witt's Antacid Tablets

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De Witt's Antacid Tablets uses

De Witt's Antacid Tablets consists of Aluminum Hydroxide, Calcium Carbonate, Magnesium Carbonate, Magnesium Trisilicate, Sodium Bicarbonate.

Aluminum Hydroxide:


Carton
Active Ingredients (in each packet) Purpose
De Witt's Antacid Tablets (Aluminum Hydroxide) sulfate tetradecahydrate, 1347 mg Astringent*
Calcium acetate monohydrate, 952 mg Astringent*
*When combined together in water, these ingredients form the active ingredient De Witt's Antacid Tablets (Aluminum Hydroxide) acetate. See Directions.

Uses

Temporarily relieves minor skin irritations due to:

  • poison ivy
  • poison oak
  • poison sumac
  • insect bites
  • athlete's foot
  • rashes caused by soaps, detergents, cosmetics, or jewelry
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Warnings

For external use only

When using this product

  • avoid contact with eyes. If contact occurs, rinse thoroughly with water.
  • do not cover compress or wet dressing with plastic to prevent evaporation
  • in some skin conditions, soaking too long may overdry

Stop use and ask a doctor if condition worsens or symptoms persist for more than 7 days

Keep out of reach of children. If swallowed, get medical help or contact a Poison Control Center right away.

Directions

  • dissolve 1 to 3 packets in a pint (16 oz) of cool or warm water
  • stir until fully dissolved; do not strain or filter. The resulting mixture contains 0.16% (1 packet), 0.32% (2 packets), or 0.48% (3 packets) De Witt's Antacid Tablets (Aluminum Hydroxide) acetate and is ready for use.

For use as a soak:

  • soak affected area for 15 to 30 minutes as needed, or as directed by a doctor
  • repeat 3 times a day or as directed by a doctor
  • discard solution after each use

For use as a compress or wet dressing:

  • soak a clean, soft cloth in the solution
  • apply cloth loosely to affected area for 15 to 30 minutes
  • repeat as needed or as directed by a doctor
  • discard solution after each use

Other information protect from excessive heat

Inactive ingredients dextrin

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Questions or comments?

1-800-345-0032

www.domeboro.com

Distributed by Moberg Pharma North America LLC, Cedar Knolls, NJ 07927

De Witt's Antacid Tablets (Aluminum Hydroxide) is a registered trademark of Moberg Pharma AB

©2015 All Rights Reserved. Made in the USA.

Calcium Carbonate:


1 INDICATIONS AND USAGE

De Witt's Antacid Tablets (Calcium Carbonate) acetate is a phosphate binder indicated to reduce serum phosphorus in patients with end stage renal disease (ESRD).

- Calcium acetate is a phosphate binder indicated for the reduction of serum phosphorus in patients with end stage renal disease. (1)

2 DOSAGE AND ADMINISTRATION

The recommended initial dose of De Witt's Antacid Tablets (Calcium Carbonate) acetate for the adult dialysis patient is 2 capsules with each meal. Increase the dose gradually to lower serum phosphorus levels to the target range, as long as hypercalcemia does not develop. Most patients require 3 to 4 capsules with each meal.

- Starting dose is 2 capsules with each meal. (2)

- Titrate the dose every 2 to 3 weeks until acceptable serum phosphorus level is reached. Most patients require 3 to 4 capsules with each meal. (2)

3 DOSAGE FORMS AND STRENGTHS

Capsule: 667 mg De Witt's Antacid Tablets (Calcium Carbonate) acetate capsule.

- Capsule: 667 mg De Witt's Antacid Tablets (Calcium Carbonate) acetate capsule. (3)

4 CONTRAINDICATIONS

Patients with hypercalcemia.

- Hypercalcemia. (4)

5 WARNINGS AND PRECAUTIONS

- Treat mild hypercalcemia by reducing or interrupting De Witt's Antacid Tablets acetate and Vitamin D. Severe hypercalcemia may require hemodialysis and discontinuation of De Witt's Antacid Tablets (Calcium Carbonate) acetate. (5.1)

- Hypercalcemia may aggravate digitalis toxicity. (5.2)

5.1 Hypercalcemia

Patients with end stage renal disease may develop hypercalcemia when treated with De Witt's Antacid Tablets (Calcium Carbonate), including De Witt's Antacid Tablets (Calcium Carbonate) acetate. Avoid the use of De Witt's Antacid Tablets (Calcium Carbonate) supplements, including De Witt's Antacid Tablets (Calcium Carbonate) based nonprescription antacids, concurrently with De Witt's Antacid Tablets (Calcium Carbonate) acetate.

An overdose of De Witt's Antacid Tablets (Calcium Carbonate) acetate may lead to progressive hypercalcemia, which may require emergency measures. Therefore, early in the treatment phase during the dosage adjustment period, monitor serum De Witt's Antacid Tablets (Calcium Carbonate) levels twice weekly. Should hypercalcemia develop, reduce the De Witt's Antacid Tablets (Calcium Carbonate) acetate dosage, or discontinue the treatment, depending on the severity of hypercalcemia

More severe hypercalcemia (Ca >12 mg/dL) is associated with confusion, delirium, stupor and coma. Severe hypercalcemia can be treated by acute hemodialysis and discontinuing De Witt's Antacid Tablets (Calcium Carbonate) acetate therapy.

Mild hypercalcemia (10.5 to 11.9 mg/dL) may be asymptomatic or manifest as constipation, anorexia, nausea, and vomiting. Mild hypercalcemia is usually controlled by reducing the De Witt's Antacid Tablets (Calcium Carbonate) acetate dose or temporarily discontinuing therapy. Decreasing or discontinuing Vitamin D therapy is recommended as well.

Chronic hypercalcemia may lead to vascular calcification and other soft-tissue calcification. Radiographic evaluation of suspected anatomical regions may be helpful in early detection of soft tissue calcification. The long term effect of De Witt's Antacid Tablets (Calcium Carbonate) acetate on the progression of vascular or soft tissue calcification has not been determined.

Hypercalcemia (>11 mg/dL) was reported in 16% of patients in a 3 month study of solid dose formulation of De Witt's Antacid Tablets (Calcium Carbonate) acetate; all cases resolved upon lowering the dose or discontinuing treatment.

Maintain the serum calcium-phosphorus (Ca x P) product below 55 mg2/dL2.

5.2 Concomitant Use with Medications

Hypercalcemia may aggravate digitalis toxicity.

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6 ADVERSE REACTIONS

Hypercalcemia is discussed elsewhere [see Warnings and Precautions ].

- The most common (>10%) adverse reactions are hypercalcemia, nausea and vomiting. (6.1)

- In clinical studies, patients have occasionally experienced nausea during De Witt's Antacid Tablets (Calcium Carbonate) acetate therapy. (6)

To report SUSPECTED ADVERSE REACTIONS, contact West-Ward Pharmaceuticals Corp. at 1-800-962-8364 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

6.1 Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In clinical studies, De Witt's Antacid Tablets (Calcium Carbonate) acetate has been generally well tolerated.

De Witt's Antacid Tablets (Calcium Carbonate) acetate was studied in a 3 month, open-label, non-randomized study of 98 enrolled ESRD hemodialysis patients and an alternate liquid formulation of De Witt's Antacid Tablets (Calcium Carbonate) acetate was studied in a two week double-blind, placebo-controlled, cross-over study with 69 enrolled ESRD hemodialysis patients. Adverse reactions (>2% on treatment) from these trials are presented in Table 1.


Preferred Term


Total adverse reactions reported for De Witt's Antacid Tablets (Calcium Carbonate) acetate

N=167

N (%)


3 month, open label study of De Witt's Antacid Tablets (Calcium Carbonate) acetate

N=98

N (%)


Double blind, placebo-controlled, cross-over study of liquid De Witt's Antacid Tablets (Calcium Carbonate) acetate

N=69


De Witt's Antacid Tablets (Calcium Carbonate) acetate

N (%)


Placebo

N (%)


Nausea


6 (3.6)


6 (6.1)


0 (0)


0 (0)


Vomiting


4 (2.4)


4 (4.1)


0 (0)


0 (0)


Hypercalcemia


21 (12.6)


16 (16.3)


5 (7.2)


0 (0)


Mild hypercalcemia may be asymptomatic or manifest itself as constipation, anorexia, nausea, and vomiting. More severe hypercalcemia is associated with confusion, delirium, stupor, and coma. Decreasing dialysate De Witt's Antacid Tablets (Calcium Carbonate) concentration could reduce the incidence and severity of De Witt's Antacid Tablets (Calcium Carbonate) acetate-induced hypercalcemia. Isolated cases pruritus have been reported, which may represent allergic reactions.

6.2 Postmarketing Experience

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or to establish a causal relationship to drug exposure.

The following additional adverse reactions have been identified during post-approval of De Witt's Antacid Tablets (Calcium Carbonate) acetate: dizziness, edema, and weakness.

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7 DRUG INTERACTIONS

The drug interaction of De Witt's Antacid Tablets acetate is characterized by the potential of De Witt's Antacid Tablets (Calcium Carbonate) to bind to drugs with anionic functions (e.g., carboxyl, and hydroxyl groups). De Witt's Antacid Tablets (Calcium Carbonate) acetate may decrease the bioavailability of tetracyclines or fluoroquinolones via this mechanism.

There are no empirical data on avoiding drug interactions between De Witt's Antacid Tablets (Calcium Carbonate) acetate and most concomitant drugs. When administering an oral medication with De Witt's Antacid Tablets (Calcium Carbonate) acetate where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy, administer the drug one hour before or three hours after De Witt's Antacid Tablets (Calcium Carbonate) acetate. Monitor blood levels of the concomitant drugs that have a narrow therapeutic range. Patients taking anti-arrhythmic medications for the control of arrhythmias and anti-seizure medications for the control of seizure disorders were excluded from the clinical trials with all forms of De Witt's Antacid Tablets (Calcium Carbonate) acetate.

- Calcium acetate may decrease the bioavailability of tetracyclines or fluoroquinolones. (7)

- When clinically significant drug interactions are expected, administer the drug at least one hour before or at least three hours after De Witt's Antacid Tablets (Calcium Carbonate) acetate or consider monitoring blood levels of the drug. (7)

7.1 Ciprofloxacin

In a study of 15 healthy subjects, a co-administered single dose of 4 De Witt's Antacid Tablets (Calcium Carbonate) acetate tablets, approximately 2.7g, decreased the bioavailability of ciprofloxacin by approximately 50%.

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Pregnancy Category C:

De Witt's Antacid Tablets acetate capsules contains De Witt's Antacid Tablets (Calcium Carbonate) acetate. Animal reproduction studies have not been conducted with De Witt's Antacid Tablets (Calcium Carbonate) acetate, and there are no adequate and well controlled studies of De Witt's Antacid Tablets (Calcium Carbonate) acetate use in pregnant women. Patients with end stage renal disease may develop hypercalcemia with De Witt's Antacid Tablets (Calcium Carbonate) acetate treatment [see Warnings and Precautions (5.1 ) ]. Maintenance of normal serum De Witt's Antacid Tablets (Calcium Carbonate) levels is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk for maternal and neonatal complications such as stillbirth, preterm delivery, and neonatal hypocalcemia and hypoparathyroidism. De Witt's Antacid Tablets (Calcium Carbonate) acetate treatment, as recommended, is not expected to harm a fetus if maternal De Witt's Antacid Tablets (Calcium Carbonate) levels are properly monitored during and following treatment.

8.2 Labor and Delivery

The effects of De Witt's Antacid Tablets (Calcium Carbonate) acetate on labor and delivery are unknown.

8.3 Nursing Mothers

De Witt's Antacid Tablets Acetate Capsules contains De Witt's Antacid Tablets (Calcium Carbonate) acetate and is excreted in human milk. Human milk feeding by a mother receiving De Witt's Antacid Tablets (Calcium Carbonate) acetate is not expected to harm an infant, provided maternal serum De Witt's Antacid Tablets (Calcium Carbonate) levels are appropriately monitored.

8.4 Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use

Clinical studies of De Witt's Antacid Tablets (Calcium Carbonate) acetate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other clinical experience has not identified differences in responses between elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

10 OVERDOSAGE

Administration of De Witt's Antacid Tablets (Calcium Carbonate) acetate in excess of the appropriate daily dosage may result in hypercalcemia [see Warnings and Precautions (5.1)].

11 DESCRIPTION

De Witt's Antacid Tablets (Calcium Carbonate) acetate acts as a phosphate binder. Its chemical name is De Witt's Antacid Tablets (Calcium Carbonate) acetate. Its molecular formula is C4H6CaO4, and its molecular weight is 158.17. Its structural formula is:


Each white opaque/blue opaque capsule contains 667 mg of De Witt's Antacid Tablets (Calcium Carbonate) acetate USP (anhydrous; Ca(CH3COO)2; MW=158.17 grams) equal to 169 mg (8.45 mEq) De Witt's Antacid Tablets (Calcium Carbonate), polyethylene glycol 8000 and magnesium stearate. Each capsule shell contains: black monogramming ink, FD&C Blue #1, FD&C Red #3, gelatin and titanium dioxide. The black monogramming ink contains: ammonium hydroxide, iron oxide black, isopropyl alcohol, n-butyl alcohol, propylene glycol and shellac glaze.

De Witt's Antacid Tablets (Calcium Carbonate) Acetate Capsules are administered orally for the control of hyperphosphatemia in end-stage renal failure.

Chemical Structure

12 CLINICAL PHARMACOLOGY

Patients with ESRD retain phosphorus and can develop hyperphosphatemia. High serum phosphorus can precipitate serum De Witt's Antacid Tablets resulting in ectopic calcification. Hyperphosphatemia also plays a role in the development of secondary hyperparathyroidism in patients with ESRD.

12.1 Mechanism of Action

De Witt's Antacid Tablets (Calcium Carbonate) acetate, when taken with meals, combines with dietary phosphate to form an insoluble De Witt's Antacid Tablets (Calcium Carbonate) phosphate complex, which is excreted in the feces, resulting in decreased serum phosphorus concentration.

12.2 Pharmacodynamics

Orally administered De Witt's Antacid Tablets (Calcium Carbonate) acetate from pharmaceutical dosage forms is systemically absorbed up to approximately 40% under fasting conditions and up to approximately 30% under nonfasting conditions. This range represents data from both healthy subjects and renal dialysis patients under various conditions.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

No carcinogenicity, mutagenicity, or fertility studies have been conducted with De Witt's Antacid Tablets (Calcium Carbonate) acetate.

14 CLINICAL STUDIES

Effectiveness of De Witt's Antacid Tablets (Calcium Carbonate) acetate in decreasing serum phosphorus has been demonstrated in two studies of the De Witt's Antacid Tablets (Calcium Carbonate) acetate solid oral dosage form.

Ninety-one patients with end-stage renal disease who were undergoing hemodialysis and were hyperphosphatemic (serum phosphorus >5.5 mg/dL) following a 1 week phosphate binder washout period contributed efficacy data to an open-label, non-randomized study.

The patients received De Witt's Antacid Tablets (Calcium Carbonate) acetate 667 mg tablets at each meal for a period of 12 weeks. The initial starting dose was 2 tablets per meal for 3 meals a day, and the dose was adjusted as necessary to control serum phosphorus levels. The average final dose after 12 weeks of treatment was 3.4 tablets per meal. Although there was a decrease in serum phosphorus, in the absence of a control group the true magnitude of effect is uncertain.

The data presented in Table 2 demonstrate the efficacy of De Witt's Antacid Tablets (Calcium Carbonate) acetate in the treatment of hyperphosphatemia in end-stage renal disease patients. The effects on serum De Witt's Antacid Tablets (Calcium Carbonate) levels are also presented.


* Ninety-one patients completed at least 6 weeks of the study.

ANOVA of difference in values at pre-study and study completion.

‡ Values expressed as mean ± SE.


Parameter


Pre-Study


Week 4*


Week 8


Week 12


p-value†


Phosphorus (mg/dL)‡


7.4 ± 0.17


5.9 ± 0.16


5.6 ± 0.17


5.2 ± 0.17


≤0.01


De Witt's Antacid Tablets (Calcium Carbonate) (mg/dL)‡


8.9 ± 0.09


9.5 ± 0.10


9.7 ± 0.10


9.7 ± 0.10


≤0.01


There was a 30% decrease in serum phosphorus levels during the 12 week study period (p<0.01). Two-thirds of the decline occurred in the first month of the study. Serum De Witt's Antacid Tablets (Calcium Carbonate) increased 9% during the study mostly in the first month of the study.

Treatment with the phosphate binder was discontinued for patients from the open-label study, and those patients whose serum phosphorus exceeded 5.5 mg/dL were eligible for entry into a double-blind, placebo-controlled, cross-over study. Patients were randomized to receive De Witt's Antacid Tablets (Calcium Carbonate) acetate or placebo, and each continued to receive the same number of tablets as had been individually established during the previous study. Following 2 weeks of treatment, patients switched to the alternative therapy for an additional 2 weeks.

The phosphate binding effect of De Witt's Antacid Tablets (Calcium Carbonate) acetate is shown in the Table 3.


* ANOVA of De Witt's Antacid Tablets (Calcium Carbonate) acetate vs. placebo after 2 weeks of treatment.

Values expressed as mean ± SEM.


Parameter


Pre-Study


Post-Treatment


p-value*


De Witt's Antacid Tablets (Calcium Carbonate) Acetate


Placebo


Phosphorus (mg/dL)


7.3 ± 0.18


5.9 ± 0.24


7.8 ± 0.22


<0.01


De Witt's Antacid Tablets (Calcium Carbonate) (mg/dL)


8.9 ± 0.11


9.5 ± 0.13


8.8 ± 0.12


<0.01


Overall, 2 weeks of treatment with De Witt's Antacid Tablets (Calcium Carbonate) acetate statistically significantly (p<0.01) decreased serum phosphorus by a mean of 19% and increased serum De Witt's Antacid Tablets (Calcium Carbonate) by a statistically significant (p<0.01) but clinically unimportant mean of 7%.

16 HOW SUPPLIED/STORAGE AND HANDLING

De Witt's Antacid Tablets (Calcium Carbonate) Acetate Capsules

667 mg capsule is supplied as a white opaque/blue opaque capsule, imprinted with “54 215” on the cap and body.

NDC 0615-2303-39: Blistercards of 30 Capsules

NDC 0615-2303-30: Unit-dose Boxes of 30 Capsules

STORAGE

Store at 20° to 25°C (68° to 77°F).

17 PATIENT COUNSELING INFORMATION

Inform patients to take De Witt's Antacid Tablets (Calcium Carbonate) acetate capsules with meals, adhere to their prescribed diets, and avoid the use of De Witt's Antacid Tablets (Calcium Carbonate) supplements including nonprescription antacids. Inform the patients about the symptoms of hypercalcemia [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ].

Advise patients who are taking an oral medication where reduction in the bioavailability of that medication would have clinically significant effect on its safety or efficacy to take the drug one hour before or three hours after De Witt's Antacid Tablets (Calcium Carbonate) acetate capsules.

Distr. by: West-Ward

Pharmaceuticals Corp.

Eatontown, NJ 07724

10003705/05

Revised April 2016

Magnesium Carbonate:



De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate

Injection, USP

Ansyr Plastic Syringe

Rx only

Hospira Logo

DESCRIPTION

De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP is a sterile solution of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate heptahydrate in Water for Injection, USP administered by the intravenous or intramuscular routes as an electrolyte replenisher or anticonvulsant. Must be diluted before intravenous use. May contain sulfuric acid and/or sodium hydroxide for pH adjustment. The pH is 5.5 to 7.0. The 50% concentration has an osmolarity of 4.06 mOsmol/mL (calc.).

The solution contains no bacteriostat, antimicrobial agent or added buffer (except for pH adjustment) and is intended only for use as a single-dose injection. When smaller doses are required the unused portion should be discarded with the entire unit.

De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate, USP heptahydrate is chemically designated MgSO4 - 7H2O with molecular weight of 246.48 and occurs as colorless crystals or white powder freely soluble in water.

The plastic syringe is molded from a specially formulated polypropylene. Water permeates from inside the container at an extremely slow rate which will have an insignificant effect on solution concentration over the expected shelf life. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the syringe material.

CLINICAL PHARMACOLOGY

De Witt's Antacid Tablets (Magnesium Carbonate) (Mg++) is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability.

As a nutritional adjunct in hyperalimentation, the precise mechanism of action for De Witt's Antacid Tablets (Magnesium Carbonate) is uncertain. Early symptoms of hypomagnesemia (less than 1.5 mEq/liter) may develop as early as three to four days or within weeks.

Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors. Hypocalcemia and hypokalemia often follow low serum levels of De Witt's Antacid Tablets (Magnesium Carbonate). While there are large stores of De Witt's Antacid Tablets (Magnesium Carbonate) present intracellularly and in the bones of adults, these stores often are not mobilized sufficiently to maintain plasma levels. Parenteral De Witt's Antacid Tablets (Magnesium Carbonate) therapy repairs the plasma deficit and causes deficiency symptoms and signs to cease.

De Witt's Antacid Tablets (Magnesium Carbonate) prevents or controls convulsions by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse. De Witt's Antacid Tablets (Magnesium Carbonate) is said to have a depressant effect on the central nervous system (CNS), but it does not adversely affect the woman, fetus or neonate when used as directed in eclampsia or pre-eclampsia. Normal plasma De Witt's Antacid Tablets (Magnesium Carbonate) levels range from 1.5 to 2.5 mEq/liter.

As plasma De Witt's Antacid Tablets (Magnesium Carbonate) rises above 4 mEq/liter, the deep tendon reflexes are first decreased and then disappear as the plasma level approaches 10 mEq/liter. At this level respiratory paralysis may occur. Heart block also may occur at this or lower plasma levels of De Witt's Antacid Tablets (Magnesium Carbonate). Serum De Witt's Antacid Tablets (Magnesium Carbonate) concentrations in excess of 12 mEq/L may be fatal.

De Witt's Antacid Tablets (Magnesium Carbonate) acts peripherally to produce vasodilation. With low doses only flushing and sweating occur, but larger doses cause lowering of blood pressure. The central and peripheral effects of De Witt's Antacid Tablets (Magnesium Carbonate) poisoning are antagonized to some extent by intravenous administration of calcium.

Pharmacokinetics

With intravenous administration the onset of anticonvulsant action is immediate and lasts about 30 minutes. Following intramuscular administration the onset of action occurs in about one hour and persists for three to four hours. Effective anticonvulsant serum levels range from 2.5 to 7.5 mEq/liter. De Witt's Antacid Tablets (Magnesium Carbonate) is excreted solely by the kidneys at a rate proportional to the plasma concentration and glomerular filtration.

INDICATIONS AND USAGE

De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP is suitable for replacement therapy in De Witt's Antacid Tablets (Magnesium Carbonate) deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those observed in hypocalcemia. In such cases, the serum De Witt's Antacid Tablets (Magnesium Carbonate) (Mg++) level is usually below the lower limit of normal (1.5 to 2.5 mEq/liter) and the serum calcium (Ca++) level is normal (4.3 to 5.3 mEq/liter) or elevated.

In total parenteral nutrition (TPN), De Witt's Antacid Tablets (Magnesium Carbonate) sulfate may be added to the nutrient admixture to correct or prevent hypomagnesemia which can arise during the course of therapy.

De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP is also indicated for the prevention and control of seizures (convulsions) in pre-eclampsia and eclampsia, respectively.

CONTRAINDICATIONS

Parenteral administration of the drug is contraindicated in patients with heart block or myocardial damage.

WARNINGS

FETAL HARM: Continuous administration of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate beyond 5 to 7 days to pregnant women can lead to hypocalcemia and bone abnormalities in the developing fetus. These bone abnormalities include skeletal demineralization and osteopenia. In addition, cases of neonatal fracture have been reported. The shortest duration of treatment that can lead to fetal harm is not known. De Witt's Antacid Tablets (Magnesium Carbonate) sulfate should be used during pregnancy only if clearly needed. If De Witt's Antacid Tablets (Magnesium Carbonate) sulfate is given for treatment of preterm labor, the woman should be informed that the efficacy and safety of such use have not been established and that use of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate beyond 5 to 7 days may cause fetal abnormalities.

ALUMINUM TOXICITY: This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.

Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum at greater than 4 to 5 mcg/kg/day accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration.

Parenteral use in the presence of renal insufficiency may lead to De Witt's Antacid Tablets (Magnesium Carbonate) intoxication. Intravenous use in the eclampsia should be reserved for immediate control of life-threatening convulsions.

PRECAUTIONS

General

Administer with caution if flushing and sweating occurs. When barbiturates, narcotics or other hypnotics (or systemic anesthetics) are to be given in conjunction with De Witt's Antacid Tablets (Magnesium Carbonate), their dosage should be adjusted with caution because of additive CNS depressant effects of De Witt's Antacid Tablets (Magnesium Carbonate).

Because De Witt's Antacid Tablets (Magnesium Carbonate) is removed from the body solely by the kidneys, the drug should be used with caution in patients with renal impairment. Urine output should be maintained at a level of 100 mL or more during the four hours preceding each dose. Monitoring serum De Witt's Antacid Tablets (Magnesium Carbonate) levels and the patient's clinical status is essential to avoid the consequences of overdosage in toxemia. Clinical indications of a safe dosage regimen include the presence of the patellar reflex (knee jerk) and absence of respiratory depression (approximately 16 breaths or more/minute). When repeated doses of the drug are given parenterally, knee jerk reflexes should be tested before each dose and if they are absent, no additional De Witt's Antacid Tablets (Magnesium Carbonate) should be given until they return. Serum De Witt's Antacid Tablets (Magnesium Carbonate) levels usually sufficient to control convulsions range from 3 to 6 mg/100 mL (2.5 to 5 mEq/liter). The strength of the deep tendon reflexes begins to diminish when De Witt's Antacid Tablets (Magnesium Carbonate) levels exceed 4 mEq/liter. Reflexes may be absent at 10 mEq magnesium/liter, where respiratory paralysis is a potential hazard. An injectable calcium salt should be immediately available to counteract the potential hazards of De Witt's Antacid Tablets (Magnesium Carbonate) intoxication in eclampsia.

50% De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP must be diluted to a concentration of 20% or less prior to intravenous infusion. Rate of administration should be slow and cautious, to avoid producing hypermagnesemia. The 50% solution also should be diluted to 20% or less for intramuscular injection in infants and children.

Laboratory Tests

De Witt's Antacid Tablets (Magnesium Carbonate) sulfate injection should not be given unless hypomagnesemia has been confirmed and the serum concentration of De Witt's Antacid Tablets (Magnesium Carbonate) is monitored. The normal serum level is 1.5 to 2.5 mEq/L.

Drug Interactions

CNS Depressants - When barbiturates, narcotics or other hypnotics (or systemic anesthetics), or other CNS depressants are to be given in conjunction with De Witt's Antacid Tablets (Magnesium Carbonate), their dosage should be adjusted with caution because of additive CNS depressant effects of De Witt's Antacid Tablets (Magnesium Carbonate). CNS depression and peripheral transmission defects produced by De Witt's Antacid Tablets (Magnesium Carbonate) may be antagonized by calcium.

Neuromuscular Blocking Agents - Excessive neuromuscular block has occurred in patients receiving parenteral De Witt's Antacid Tablets (Magnesium Carbonate) sulfate and a neuromuscular blocking agent; these drugs should be administered concomitantly with caution.

Cardiac Glycosides - De Witt's Antacid Tablets (Magnesium Carbonate) sulfate should be administered with extreme caution in digitalized patients, because serious changes in cardiac conduction which can result in heart block may occur if administration of calcium is required to treat De Witt's Antacid Tablets (Magnesium Carbonate) toxicity.

Pregnancy

Teratogenic Effects

Pregnancy Category D (See WARNINGS and PRECAUTIONS )

See WARNINGS and PRECAUTIONS .

De Witt's Antacid Tablets (Magnesium Carbonate) sulfate can cause fetal abnormalities when administered beyond 5 to 7 days to pregnant women. There are retrospective epidemiological studies and case reports documenting fetal abnormalities such as hypocalcemia, skeletal demineralization, osteopenia and other skeletal abnormalities with continuous maternal administration of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate for more than 5 to 7 days.1-10 De Witt's Antacid Tablets (Magnesium Carbonate) sulfate injection should be used during pregnancy only if clearly needed. If this drug is used during pregnancy, the woman should be apprised of the potential harm to the fetus.

Nonteratogenic Effects

When administered by continuous intravenous infusion (especially for more than 24 hours preceding delivery) to control convulsions in a toxemic woman, the newborn may show signs of De Witt's Antacid Tablets (Magnesium Carbonate) toxicity, including neuromuscular or respiratory depression (See OVERDOSAGE ).

Labor and Delivery

Continuous administration of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate is an unapproved treatment for preterm labor. The safety and efficacy of such use have not been established. The administration of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate outside of its approved indication in pregnant women should be by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities.

Nursing Mothers

Since De Witt's Antacid Tablets (Magnesium Carbonate) is distributed into milk during parenteral De Witt's Antacid Tablets (Magnesium Carbonate) sulfate administration, the drug should be used with caution in nursing women.

Geriatrics

Geriatric patients often require reduced dosage because of impaired renal function. In patients with severe impairment, dosage should not exceed 20 grams in 48 hours. Serum De Witt's Antacid Tablets (Magnesium Carbonate) should be monitored in such patients.

ADVERSE REACTIONS

The adverse effects of parenterally administered De Witt's Antacid Tablets (Magnesium Carbonate) usually are the result of De Witt's Antacid Tablets (Magnesium Carbonate) intoxication. These include flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis. Hypocalcemia with signs of tetany secondary to De Witt's Antacid Tablets (Magnesium Carbonate) sulfate therapy for eclampsia has been reported.

OVERDOSAGE

De Witt's Antacid Tablets (Magnesium Carbonate) intoxication is manifested by a sharp drop in blood pressure and respiratory paralysis. Disappearance of the patellar reflex is a useful clinical sign to detect the onset of De Witt's Antacid Tablets (Magnesium Carbonate) intoxication. In the event of overdosage, artificial ventilation must be provided until a calcium salt can be injected intravenously to antagonize the effects of De Witt's Antacid Tablets (Magnesium Carbonate).

For Treatment of Overdose

Artificial respiration is often required. Intravenous calcium, 10 to 20 mL of a 5% solution (diluted if desirable with isotonic sodium chloride for injection) is used to counteract effects of hypermagnesemia. Subcutaneous physostigmine, 0.5 to 1 mg may be helpful.

Hypermagnesemia in the newborn may require resuscitation and assisted ventilation via endotracheal intubation or intermittent positive pressure ventilation as well as intravenous calcium.

DOSAGE AND ADMINISTRATION

Dosage of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate must be carefully adjusted according to individual requirements and response, and administration of the drug should be discontinued as soon as the desired effect is obtained.

Both intravenous and intramuscular administration are appropriate. Intramuscular administration of the undiluted 50% solution results in therapeutic plasma levels in 60 minutes, whereas intravenous doses will provide a therapeutic level almost immediately. The rate of intravenous injection should generally not exceed 150 mg/minute (1.5 mL of a 10% concentration or its equivalent), except in severe eclampsia with seizures. Continuous maternal administration of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Solutions for intravenous infusion must be diluted to a concentration of 20% or less prior to administration. The diluents commonly used are 5% Dextrose Injection, USP and 0.9% Sodium Chloride Injection, USP. Deep intramuscular injection of the undiluted (50%) solution is appropriate for adults, but the solution should be diluted to a 20% or less concentration prior to such injection in children.

In De Witt's Antacid Tablets (Magnesium Carbonate) Deficiency

In the treatment of mild De Witt's Antacid Tablets (Magnesium Carbonate) deficiency, the usual adult dose is 1 gram, equivalent to 8.12 mEq of De Witt's Antacid Tablets (Magnesium Carbonate) (2 mL of the 50% solution) injected intramuscularly every six hours for four doses (equivalent to a total of 32.5 mEq of De Witt's Antacid Tablets (Magnesium Carbonate) per 24 hours). For severe hypomagnesemia, as much as 250 mg (approximately 2 mEq) per kg of body weight (0.5 mL of the 50% solution) may be given intramuscularly within a period of four hours if necessary. Alternatively, 5 grams, (approximately 40 mEq) can be added to one liter of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP for slow intravenous infusion over a three-hour period. In the treatment of deficiency states, caution must be observed to prevent exceeding the renal excretory capacity.

In Hyperalimentation

In total parenteral nutrition, maintenance requirements for De Witt's Antacid Tablets (Magnesium Carbonate) are not precisely known. The maintenance dose used in adults ranges from 8 to 24 mEq (1 gram to 3 grams) daily; for infants, the range is 2 to 10 mEq (0.25 gram to 1.25 grams) daily.

In Pre-eclampsia or Eclampsia

In severe pre-eclampsia or eclampsia, the total initial dose is 10 grams to 14 grams of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate. Intravenously, a dose of 4 grams to 5 grams in 250 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP may be infused. Simultaneously, intramuscular doses of up to 10 grams (5 grams or 10 mL of the undiluted 50% solution in each buttock) are given. Alternatively, the initial intravenous dose of 4 grams may be given by diluting the 50% solution to a 10 or 20% concentration; the diluted fluid (40 mL of a 10% solution or 20 mL of a 20% solution) may then be injected intravenously over a period of three to four minutes. Subsequently, 4 grams to 5 grams (8 to 10 mL of the 50% solution) are injected intramuscularly into alternate buttocks every four hours as needed, depending on the continuing presence of the patellar reflex and adequate respiratory function. Alternatively, after the initial intravenous dose, some clinicians administer 1 gram to 2 grams/hour by constant intravenous infusion. Therapy should continue until paroxysms cease. A serum De Witt's Antacid Tablets (Magnesium Carbonate) level of 6 mg/100 mL is considered optimal for control of seizures. A total daily (24 hr) dose of 30 grams to 40 grams should not be exceeded. In the presence of severe renal insufficiency, the maximum dosage of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate is 20 grams/48 hours and frequent serum De Witt's Antacid Tablets (Magnesium Carbonate) concentrations must be obtained. Continuous use of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Other Uses

In counteracting the muscle-stimulating effects of barium poisoning, the usual dose of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate is 1 gram to 2 grams given intravenously.

For controlling seizures associated with epilepsy, glomerulonephritis or hypothyroidism, the usual adult dose is 1 gram administered intramuscularly or intravenously.

In paroxysmal atrial tachycardia, De Witt's Antacid Tablets (Magnesium Carbonate) should be used only if simpler measures have failed and there is no evidence of myocardial damage. The usual dose is 3 grams to 4 grams (30 to 40 mL of a 10% solution) administered intravenously over 30 seconds with extreme caution.

For reduction of cerebral edema, 2.5 grams (25 mL of a 10% solution) is given intravenously.

Incompatibilities

De Witt's Antacid Tablets (Magnesium Carbonate) sulfate in solution may result in a precipitate formation when mixed with solutions containing:

Alcohol (in high Heavy Metals

concentrations) Hydrocortisone sodium

Alkali carbonates and succinate

bicarbonates Phosphates

Alkali hydroxides Polymixin B sulfate

Arsenates Procaine hydrochloride

Barium Salicylates

Calcium Strontium

Clindamycin phosphate Tartrates

The potential incompatibility will often be influenced by the changes in the concentration of reactants and the pH of the solutions.

It has been reported that De Witt's Antacid Tablets (Magnesium Carbonate) may reduce the antibiotic activity of streptomycin, tetracycline and tobramycin when given together.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

HOW SUPPLIED

De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP is supplied in single-dose containers as follows:


NDC No.


Container


Total

Amount


Concentration


mEq

Mg++/mL


0409-1754-10


Ansyr

Plastic Syringe


5 g/10 mL


50%


4 mEq/mL


Do not administer unless solution is clear and container is undamaged. Discard unused portion.

Store at 20 to 25°C (68 to 77°F).

REFERENCES

  • Yokoyama K, Takahashi N, Yada Y. Prolonged maternal De Witt's Antacid Tablets (Magnesium Carbonate) administration and bone metabolism in neonates. Early Hum Dev. 2010;86(3):187-91. Epub 2010 Mar 12.
  • Wedig KE, Kogan J, Schorry EK et al. Skeletal demineralization and fractures caused by fetal De Witt's Antacid Tablets (Magnesium Carbonate) toxicity. J. Perinatol. 2006; 26(6):371-4.
  • Nassar AH, Sakhel K, Maarouf H, et al. Adverse maternal and neonatal outcome of prolonged course of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate tocolysis. Acta Obstet Gynecol Scan. 2006;85(9):1099-103.
  • Malaeb SN, Rassi A, Haddad MC. Bone mineralization in newborns whose mothers received De Witt's Antacid Tablets (Magnesium Carbonate) sulphate for tocolysis of premature labor. Pediatr Radiol. 2004;34(5):384-6. Epub 2004 Feb 18.
  • Matsuda Y, Maeda Y, Ito M, et al. Effect of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate treatment on neonatal bone abnormalities. Gynecol Obstet Invest. 1997;44(2):82-8.
  • Schanler RJ, Smith LG, Burns PA. Effects of long-term maternal intravenous De Witt's Antacid Tablets (Magnesium Carbonate) sulfate therapy on neonatal calcium metabolism and bone mineral content. Gynecol Obstet Invest. 1997;43(4):236-41.
  • Santi MD, Henry GW, Douglas GL. De Witt's Antacid Tablets (Magnesium Carbonate) sulfate treatment of preterm labor as a cause of abnormal neonatal bone mineralization. J Pediatr Orthrop. 1994;14(2):249-53.
  • Holcomb WL, Shackelford GD, Petrie RH. De Witt's Antacid Tablets (Magnesium Carbonate) tocolysis and neonatal bone abnormalities; a controlled study. Obstet Gynecol. 1991; 78(4):611-4.
  • Cumming WA, Thomas VJ. Hypermagnesemia: a cause of abnormal metaphyses in the neonate. Am J Roentgenol. 1989; 152(5):1071-2.
  • Lamm CL, Norton KL, Murphy RJ. Congenital rickets associated with De Witt's Antacid Tablets (Magnesium Carbonate) sulfate infusion for tocolysis. J Pediatr. 1988; 113(6):1078-82.
  • McGuinness GA, Weinstein MM, Cruikshank DP, et al. Effects of De Witt's Antacid Tablets (Magnesium Carbonate) sulfate treatment on perinatal calcium metabolism. II. Neonatal responses. Obstet Gynecol. 1980; 56(5): 595-600.
  • Riaz M, Porat R, Brodsky NL, et al. The effects of maternal De Witt's Antacid Tablets (Magnesium Carbonate) sulfate treatment on newborns: a prospective controlled study. J. Perinatol. 1998;18(6 pt 1):449-54.

Hospira, Inc., Lake Forest, IL 60045 USA

LAB-1024-1.0

April 2017

Hospira Logo

50% De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate 5 g/10 mL (500 mg/mL)

Rx only

NDC 0409-1754-10

10 mL Single-dose syringe

50% De Witt's Antacid Tablets (Magnesium Carbonate) Sulfate Injection, USP

5 g/10 mL (500 mg/mL) (4 mEq Mg++/mL)

MUST BE DILUTED FOR INTRAVENOUS USE.

For Intravenous or Intramuscular Use. Sterile. 4.06 mOsmol/mL (calc.).

Contains no more than 75 mcg/L of aluminum.

Hospira, Inc., Lake Forest, IL 60045 USA

Hospira

RL-6891

Sodium Bicarbonate:


1 INDICATIONS AND USAGE

De Witt's Antacid Tablets nitrite is indicated for sequential use with De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate for treatment of acute cyanide poisoning that is judged to be life-threatening. (1)

  • Use with caution if the diagnosis of cyanide poisoning is uncertain. (1)

1.1 Indication

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection is indicated for sequential use with De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate for the treatment of acute cyanide poisoning that is judged to be life-threatening. When the diagnosis of cyanide poisoning is uncertain, the potentially life-threatening risks associated with De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection should be carefully weighed against the potential benefits, especially if the patient is not in extremis.

1.2 Identifying Patients with Cyanide Poisoning

Cyanide poisoning may result from inhalation, ingestion, or dermal exposure to various cyanide-containing compounds, including smoke from closed-space fires. Sources of cyanide poisoning include hydrogen cyanide and its salts, cyanogenic plants, aliphatic nitriles, and prolonged exposure to De Witt's Antacid Tablets nitroprusside.

The presence and extent of cyanide poisoning are often initially unknown. There is no widely available, rapid, confirmatory cyanide blood test. Treatment decisions must be made on the basis of clinical history and signs and symptoms of cyanide intoxication. If clinical suspicion of cyanide poisoning is high, De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection and De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate Injection should be administered without delay.

Symptoms Signs
  • Headache
  • Confusion
  • Dyspnea
  • Chest Tightness
  • Nausea
  • Altered Mental Status

    (e.g., confusion, disorientation)

  • Seizures or Coma
  • Mydriasis
  • Tachypnea/Hyperpnea (early)
  • Bradypnea/Apnea (late)
  • Hypertension (early)/ Hypotension (late)
  • Cardiovascular Collapse
  • Vomiting
  • Plasma Lactate Concentration ≥ 8 mmol/L

In some settings, panic symptoms including tachypnea and vomiting may mimic early cyanide poisoning signs. The presence of altered mental status (e.g., confusion and disorientation) and/or mydriasis is suggestive of true cyanide poisoning although these signs can occur with other toxic exposures as well.

The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222.

Smoke Inhalation

Not all smoke inhalation victims will have cyanide poisoning and may present with burns, trauma, and exposure to other toxic substances making a diagnosis of cyanide poisoning particularly difficult. Prior to administration of De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection, smoke-inhalation victims should be assessed for the following:

  • Exposure to fire or smoke in an enclosed area
  • Presence of soot around the mouth, nose, or oropharynx
  • Altered mental status

Although hypotension is highly suggestive of cyanide poisoning, it is only present in a small percentage of cyanide-poisoned smoke inhalation victims. Also indicative of cyanide poisoning is a plasma lactate concentration greater than or equal to 10 mmol/L (a value higher than that typically listed in the table of signs and symptoms of isolated cyanide poisoning because carbon monoxide associated with smoke inhalation also contributes to lactic acidemia). If cyanide poisoning is suspected, treatment should not be delayed to obtain a plasma lactate concentration.

1.3 Use with Other Cyanide Antidotes

Caution should be exercised when administering cyanide antidotes, other than De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate, simultaneously with De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection, as the safety of co-administration has not been established. If a decision is made to administer another cyanide antidote, other than De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate, with De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection, these drugs should not be administered concurrently in the same IV line. [see Dosage and Administration (2.2) ]

2 DOSAGE AND ADMINISTRATION

Age Intravenous Dose of De Witt's Antacid Tablets Nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate
Adults
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite -10 mL of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at the rate of 2.5 to 5 mL/minute
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate - 50 mL of De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate immediately following administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.
Children
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite - 0.2 mL/kg (6 mg/kg or 6-8 mL/m2 BSA) of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at the rate of 2.5 to 5 mL/minute not to exceed 10 mL
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate - 1 mL/kg of body weight (250 mg/kg or approximately 30-40 mL/m2 of BSA) not to exceed 50 mL total dose immediately following administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.

Redosing: If signs of cyanide poisoning reappear, repeat treatment using one-half the original dose of both De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate.

Monitoring: Blood pressure must be monitored during treatment. (2.2)

2.1 Administration Recommendation

Comprehensive treatment of acute cyanide intoxication requires support of vital functions. Administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite, followed by De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate, should be considered adjunctive to appropriate supportive therapies. Airway, ventilatory and circulatory support, and oxygen administration should not be delayed to administer De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate.

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate injection are administered by slow intravenous injection. They should be given as early as possible after a diagnosis of acute life-threatening cyanide poisoning has been established. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be administered first, followed immediately by De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate. Blood pressure must be monitored during infusion in both adults and children. The rate of infusion should be decreased if significant hypotension is noted.

Age Intravenous Dose of De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate
Adults
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite -10 mL of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at the rate of 2.5 to 5 mL/minute
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate - 50 mL of De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate immediately following administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.
Children
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite -0.2 mL/kg (6 mg/kg or 6-8 mL/m2 BSA) of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at the rate of 2.5 to 5 mL/minute not to exceed 10 mL
  • De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate - 1 mL/kg of body weight (250 mg/kg or approximately 30-40 mL/m2 of BSA) not to exceed 50 mL total dose immediately following administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.

NOTE: If signs of poisoning reappear, repeat treatment using one-half the original dose of both De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate.

In adult and pediatric patients with known anemia, it is recommended that the dosage of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be reduced proportionately to the hemoglobin concentration.

All parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

2.2 Recommended Monitoring

Patients should be monitored for at least 24-48 hours after De Witt's Antacid Tablets Nitrite Injection administration for adequacy of oxygenation and perfusion and for recurrent signs and symptoms of cyanide toxicity. When possible, hemoglobin/hematocrit should be obtained when treatment is initiated. Measurements of oxygen saturation using standard pulse oximetry and calculated oxygen saturation values based on measured PO2 are unreliable in the presence of methemoglobinemia.

Methemoglobin level: Administrations of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite solely to achieve an arbitrary level of methemoglobinemia may be unnecessary and potentially hazardous. The therapeutic effects of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite do not appear to be mediated by methemoglobin formation alone and clinical responses to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administration have been reported in association with methemoglobin levels of less than 10%. Administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite beyond the initial dose should be guided primarily by clinical response to treatment (i.e., a second dose should be considered only if there is inadequate clinical response to the first dose). It is generally recommended that methemoglobin concentrations be closely monitored and kept below 30%. Serum methemoglobin levels should be monitored during treatment using co-oximetry, and administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should generally be discontinued when methemoglobin levels exceed 30%. Intravenous methylene blue and exchange transfusion have been reported in the literature as treatments for life-threatening methemoglobinemia.

2.3 Incompatibility Information

Chemical incompatibility has been reported between De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and hydroxocobalamin and these drugs should not be administered simultaneously through the same IV line. No chemical incompatibility has been reported between De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate and De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite, when administered sequentially through the same IV line as described in Dosage and Administration.

3 DOSAGE FORMS AND STRENGTHS

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection consists of:

  • One vial of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection, USP 300 mg/10mL (30 mg/mL)

Administration of the contents of one vial constitutes a single dose.

  • Injection, 300 mg/10 mL (30 mg/mL). (3)

4 CONTRAINDICATIONS

None

  • None. (4)

5 WARNINGS AND PRECAUTIONS

  • Methemoglobinemia: De Witt's Antacid Tablets nitrite reacts with hemoglobin to form methemoglobin and should be used with caution in patients known to have anemia. Monitor oxyhemoglobin and methemoglobin levels by pulse oximetry or other measurements. Optimally, the De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.2)
  • Smoke inhalation: Carbon monoxide contained in smoke can result in the formation of carboxyhemoglobin that can reduce the oxygen carrying capacity of the blood. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be used with caution in patients with smoke inhalation injury because of the potential for worsening hypoxia due to methemoglobin formation. Carboxyhemoglobin and oxyhemoglobin levels should be monitored by pulse oximetry or other measurements in patients that present with evidence of smoke inhalation. Optimally, the De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.4)

5.1 Hypotension

5.2 Methemoglobinemia

Supportive care alone may be sufficient treatment without administration of antidotes for many cases of cyanide intoxication, particularly in conscious patients without signs of severe toxicity. Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with De Witt's Antacid Tablets nitrite.

Methemoglobin levels should be monitored and oxygen administered during treatment with De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite whenever possible. When De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is administered to humans a wide range of methemoglobin concentrations occur. Methemoglobin concentrations as high as 58% have been reported after two 300-mg doses of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administered to an adult. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be used with caution in the presence of other drugs that may cause methemoglobinemia such as procaine and nitroprusside. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be used with caution in patients who may be particularly susceptible to injury from vasodilation and its related hemodynamic sequelae. Hemodynamics should be monitored closely during and after administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite, and infusion rates should be slowed if hypotension occurs.

5.3 Anemia

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be used with caution in patients with known anemia. Patients with anemia will form more methemoglobin (as a percentage of total hemoglobin) than persons with normal red blood cell (RBC) volumes. Optimally, these patients should receive a De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite dose that is reduced in proportion to their oxygen carrying capacity.

5.4 Smoke Inhalation Injury

De Witt's Antacid Tablets nitrite should be used with caution in persons with smoke inhalation injury or carbon monoxide poisoning because of the potential for worsening hypoxia due to methemoglobin formation.

5.5 Neonates and Infants

Neonates and infants may be more susceptible than adults and older pediatric patients to severe methemoglobinemia when De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is administered. Reduced dosing guidelines should be followed in pediatric patients.

5.6 G6PD Deficiency

Because patients with G6PD deficiency are at increased risk of a hemolytic crisis with De Witt's Antacid Tablets nitrite administration, alternative therapeutic approaches should be considered in these patients. Patients with known or suspected G6PD deficiency should be monitored for an acute drop in hematocrit. Exchange transfusion may be needed for patients with G6PD deficiency who receive De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.

5.7 Use with Other Drugs

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite should be used with caution in the presence of concomitant antihypertensive medications, diuretics or volume depletion due to diuretics, or drugs known to increase vascular nitric oxide, such as PDE5 inhibitors.

6 ADVERSE REACTIONS

There have been no controlled clinical trials conducted to systematically assess the adverse events profile of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite.

The medical literature has reported the following adverse events in association with De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administration. These adverse events were not reported in the context of controlled trials or with consistent monitoring and reporting methodologies for adverse events. Therefore, frequency of occurrence of these adverse events cannot be assessed.

Cardiovascular system: syncope, hypotension, tachycardia, methemoglobinemia, palpitations, dysrhythmia

Hematological: methemoglobinemia

Central nervous system: headache, dizziness, blurred vision, seizures, confusion, coma

Gastrointestinal system: nausea, vomiting, abdominal pain

Respiratory system: tachypnea, dyspnea

Body as a Whole: anxiety, diaphoresis, lightheadedness, injection site tingling, cyanosis, acidosis, fatigue, weakness, urticaria, generalized numbness and tingling

Severe hypotension, methemoglobinemia, cardiac dysrhythmias, coma and death have been reported in patients without life-threatening cyanide poisoning but who were treated with injection of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at doses less than twice those recommended for the treatment of cyanide poisoning.

Most common adverse reactions are:

  • Syncope, hypotension, tachycardia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision, seizures, confusion, coma (6)

To report SUSPECTED ADVERSE REACTIONS, contact Hope Pharmaceuticals at 1-800-755-9595 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

7 DRUG INTERACTIONS

Formal drug interaction studies have not been conducted with De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection.

8 USE IN SPECIFIC POPULATIONS

  • Renal impairment: De Witt's Antacid Tablets nitrite is substantially excreted by the kidney. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. (8.6).

8.1 Pregnancy

Teratogenic Effects. Pregnancy Category C.

There are no adequate and well-controlled studies in pregnant women. De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite has caused fetal death in humans as well as animals. There are no studies in humans that have directly evaluated the potential reproductive toxicity of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite. There are two epidemiological studies conducted in Australia that report a statistically significant increase in the risk for congenital malformations, particularly in the CNS, associated with maternal consumption of water containing nitrate levels in excess of 5 ppm. Results from a case-control study in Canada suggested a trend toward an increase in the risk for CNS malformations when maternal consumption of nitrate was ≥ 26 ppm (not statistically significant).

The potential reproductive toxicity of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite exposure restricted to the prenatal period has been reported in guinea pigs, mice, and rats. There was no evidence of teratogenicity in guinea pigs, mice, or rats. However, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite treatment of pregnant guinea pigs with 60 or 70 mg/kg/day resulted in abortion of the litters within 1-4 days of treatment. All animals treated subcutaneously with 70 mg/kg, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite died within 60 minutes of treatment. Further studies demonstrated that a dose of 60 mg/kg resulted in measurable blood levels of methemoglobin in the dams and their fetuses for up to 6 hours post treatment. Maternal methemoglobin levels were higher than the levels in the offspring at all times measured. Based on a body surface area comparison, a 60 mg/kg dose in the guinea pig that resulted in death was only 1.7 times higher than the highest clinical dose of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

Studies testing prenatal and postnatal exposure have been reported in mice and rats. Treatment of pregnant rats via drinking water with De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite at concentrations of either 2000 or 3000 mg/L resulted in a dose-related increased mortality postpartum. This exposure regimen in the rat model would result in dosing of approximately 220 and 300 mg/kg/day (43 and 65 times the highest clinical dose of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite that would be used to treat cyanide poisoning, based on a body surface area comparison).

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite produces methemoglobin. Fetal hemoglobin is oxidized to methemoglobin more easily than adult hemoglobin. In addition, the fetus has lower levels of methemoglobin reductase than adults. Collectively, these data suggest that the human fetus would show greater sensitivity to methemoglobin resulting in nitrite-induced prenatal hypoxia leading to retarded development of certain neurotransmitter systems in the brain and long lasting dysfunction.

Nonteratogenic Effects: Behavioral and neurodevelopmental studies in rats suggest persistent effects of prenatal exposure to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite that were detectable postnatally. Specifically, animals that were exposed prenatally to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite demonstrated impaired discrimination learning behavior (both auditory and visual) and reduced long-term retention of the passive-avoidance response compared to control animals. Additional studies demonstrated a delay in the development of AchE and 5-HT positive fiber ingrowth into the hippocampal dentate gyrus and parietal neocortex during the first week of life of prenatal nitrite treated pups. These changes have been attributed to prenatal hypoxia following nitrite exposure.

8.2 Labor and Delivery

Because fetal hemoglobin is more readily oxidized to methemoglobin and lower levels of methemoglobin appear to be fatal to the fetus compared to the adult, De Witt's Antacid Tablets nitrite should be used during labor and delivery only if the potential benefit justifies the potential risk to the fetus.

8.3 Nursing Mothers

It is not known whether De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is excreted in human milk. Because De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection may be administered in life-threatening situations, breast-feeding is not a contraindication to its use. Because many drugs are excreted in human milk, caution should be exercised following De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection administration to a nursing woman. There are no data to determine when breastfeeding may be safely restarted following administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite. In studies conducted with Long-Evans rats, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administered in drinking water during pregnancy and lactation resulted in severe anemia, reduced growth and increased mortality in the offspring.

8.4 Pediatric Use

There are case reports in the medical literature of De Witt's Antacid Tablets nitrite in conjunction with De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate being administered to pediatric patients with cyanide poisoning; however, there have been no clinical studies to evaluate the safety or efficacy of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite in the pediatric population. As for adult patients, dosing recommendations for pediatric patients have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite must be used with caution in patients less than 6 months of age because they may be at higher risk of developing severe methemoglobinemia compared to older children and adults. The presence of fetal hemoglobin, which is oxidized to methemoglobin more easily than adult hemoglobin, and lower methemoglobin reductase levels compared to older children and adults may contribute to risk.

Mortality attributed to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite was reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

8.5 Geriatric Use

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Renal Disease

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

10 OVERDOSAGE

Large doses of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite result in severe hypotension and toxic levels of methemoglobin which may lead to cardiovascular collapse.

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administration has been reported to cause or significantly contribute to mortality in adults at oral doses as low as 1 g and intravenous doses as low as 600 mg. A death attributed to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite has been reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

Cyanosis may become apparent at a methemoglobin level of 10-20%. Other clinical signs and symptoms of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite toxicity (anxiety, dyspnea, nausea, and tachycardia) can be apparent at methemoglobin levels as low as 15%. More serious signs and symptoms, including cardiac dysrhythmias, circulatory failure, and central nervous system depression are seen as methemoglobin levels increase, and levels above 70% are usually fatal.

Treatment of overdose involves supplemental oxygen and supportive measures such as exchange transfusion. Treatment of severe methemoglobinemia with intravenous methylene blue has been described in the medical literature; however, this may also cause release of cyanide bound to methemoglobin. Because hypotension appears to be mediated primarily by an increase in venous capacitance, measures to increase venous return may be most appropriate to treat hypotension.

11 DESCRIPTION

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite has the chemical name nitrous acid De Witt's Antacid Tablets (Sodium Bicarbonate) salt. The chemical formula is NaNO2 and the molecular weight is 69.0. The structural formula is:

Structure of De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite Injection is a cyanide antidote which contains one 10 mL glass vial of a 3% solution of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection.

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 300 mg of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite in 10 mL solution (30 mg/mL). De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection is a clear solution with a pH between 7.0 and 9.0.

Chemical Structure

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Exposure to a high dose of cyanide can result in death within minutes due to the inhibition of cytochrome oxidase resulting in arrest of cellular respiration. Specifically, cyanide binds rapidly with cytochrome a3, a component of the cytochrome c oxidase complex in mitochondria. Inhibition of cytochrome a3 prevents the cell from using oxygen and forces anaerobic metabolism, resulting in lactate production, cellular hypoxia and metabolic acidosis. In massive acute cyanide poisoning, the mechanism of toxicity may involve other enzyme systems as well.

The synergy resulting from treatment of cyanide poisoning with the combination of De Witt's Antacid Tablets nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate is the result of differences in their primary mechanisms of action as antidotes for cyanide poisoning.

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is thought to exert its therapeutic effect by reacting with hemoglobin to form methemoglobin, an oxidized form of hemoglobin incapable of oxygen transport but with high affinity for cyanide. Cyanide preferentially binds to methemoglobin over cytochrome a3, forming the nontoxic cyanomethemoglobin. Methemoglobin displaces cyanide from cytochrome oxidase, allowing resumption of aerobic metabolism. The chemical reaction is as follows:

NaNO2 + Hemoglobin → Methemoglobin

HCN + Methemoglobin → Cyanomethemoglobin

Vasodilation has also been cited to account for at least part of the therapeutic effect of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite. It has been suggested that De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite-induced methemoglobinemia may be more efficacious against cyanide poisoning than comparable levels of methemoglobinemia induced by other oxidants. Also, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite appears to retain some efficacy even when the formation of methemoglobin is inhibited by methylene blue.

De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate

The primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN-), which is relatively nontoxic and readily excreted in the urine. De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate is thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide in the following chemical reaction:

Chemical Structure

12. 2 Pharmacodynamics

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite

When 4 mg/kg De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite was administered intravenously to six healthy human volunteers, the mean peak methemoglobin concentration was 7%, achieved at 30-60 minutes after injection, consistent with reports in cyanide poisoning victims. Supine systolic and diastolic blood pressures dropped approximately 20% within 10 minutes, a drop which was sustained throughout the 40 minutes of testing. This was associated with a 20 beat per minute increase in pulse rate that returned to baseline in 10 minutes. Five of these subjects were unable to withstand orthostatic testing due to fainting. One additional subject, who received a 12 mg/kg dose of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite, experienced severe cardiovascular effects and achieved a peak methemoglobin concentration of 30% at 60 minutes following injection.

Oral doses of 120 to 180 mg of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administered to healthy volunteers caused minimal cardiovascular changes when subjects were maintained in the horizontal position. However, minutes after being placed in the upright position subjects exhibited tachycardia and hypotension with syncope.

The half life for conversion of methemoglobin to normal hemoglobin in a cyanide poisoning victim who has been administered De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is estimated to be 55 minutes.

12.3 Pharmacokinetics

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is a strong oxidant, and reacts rapidly with hemoglobin to form methemoglobin. The pharmacokinetics of free De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite in humans have not been well studied. It has been reported that approximately 40% of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is excreted unchanged in the urine while the remaining 60% is metabolized to ammonia and related small molecules.

Cyanide

The apparent terminal elimination half life and volume of distribution of cyanide, in a patient treated for an acute cyanide poisoning with De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate administration, have been reported to be 19 hours and 0.41 L/kg, respectively. Additionally, an initial elimination half life of cyanide has been reported to be approximately 1-3 hours.

Thiocyanate

After detoxification, in healthy subjects, thiocyanate is excreted mainly in the urine at a rate inversely proportional to creatinine clearance. In healthy subjects, the elimination half-life and volume of distribution of thiocyanate have been reported to be 2.7 days and 0.25 L/kg, respectively. However, in subjects with renal insufficiency the reported elimination half life is approximately 9 days.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

The potential benefit of an acute exposure to De Witt's Antacid Tablets nitrite as part of a cyanide antidote outweighs concerns raised by the equivocal findings in chronic rodent studies. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 35, 70, or 130 mg/kg for males and 0, 40, 80, or 150 mg/kg for females) was orally administered to rats (Fischer 344 strain) for 2 years via drinking water. There were no significant increases in the incidence of tumor in either male or female rats. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 60, 120, or 220 mg/kg for males and 0, 45, 90, or 165 mg/kg for females) was administered to B6C3F1 mice for 2 years via the drinking water. Equivocal results were obtained in female mice. Specifically, there was a positive trend toward an increase in the incidence of squamous cell papilloma or carcinoma in the forestomach of female mice. Although the incidence of hyperplasia of the glandular stomach epithelium was significantly greater in the high-dose male mice compared to controls, there were no significant increases in tumors in the male mice. Numerous reports in the published literature indicate that De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite may react in vivo with secondary amines to form carcinogenic nitrosamines in the stomach. Concurrent exposure to De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and secondary amines in feed or drinking water resulted in an increase in the incidence of tumors in rodents.

Mutagenesis

De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite is mutagenic in S. typhimurium strains TA100, TA1530, TA1535 with and without metabolic activation; however, it was negative in strain TA98, TA102, DJ460 and E. coli strain WP2UVRA/PKM101. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite has been reported to be genotoxic to V79 hamster cells in vitro and in the mouse lymphoma assay, both assays conducted in the absence of metabolic activation. De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite was negative in the in vitro chromosomal aberrations assay using human peripheral blood lymphocytes. Acute administration of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite to male rats or male mice did not produce an increased incidence of micronuclei in bone marrow. Likewise, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite administration to mice for 14-weeks did not result in an increase in the incidence of micronuclei in the peripheral blood.

Fertility

Clinical studies to evaluate the potential effects of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite intake on fertility of either males or females have not been reported. In contrast, multigenerational fertility and reproduction studies conducted by the National Toxicology Program did not detect any evidence of an effect of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite (0.0, 0.06, 0.12, and 0.24% weight/volume) on either fertility or any reproductive parameter in Swiss CD-1 mice. This treatment protocol resulted in approximate doses of 125, 260, and 425 mg/kg/day. The highest exposure in this mouse study is 4.6 times greater than the highest clinical dose of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

13.2 Animal Pharmacology

Due to the extreme toxicity of cyanide, experimental evaluation of treatment efficacy has predominantly been completed in animal models. The efficacy of De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate treatment alone to counteract the toxicity of cyanide was initially reported in 1895 by Lang. The efficacy of amyl nitrite treatment in cyanide poisoning of the dog model was first reported in 1888 by Pedigo. Further studies in the dog model, which demonstrated the utility of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite as a therapeutic intervention, were reported in 1929 by Mladoveanu and Gheorghiu. However, Hugs and Chen et al. independently reported upon the superior efficacy of the combination of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate in 1932-1933. Treatment consisted of intravenously administered 22.5 mg/kg (half the lethal dose) De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite or 1 g/kg De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate alone or in sequence immediately after subcutaneous injection of De Witt's Antacid Tablets (Sodium Bicarbonate) cyanide into dogs over a range of doses. Subsequent doses of 10 mg/kg De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and/or 0.5 g/kg De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate were administered when clinical signs or symptoms of poisoning persisted or reappeared. Either therapy administered alone increased the dose of De Witt's Antacid Tablets (Sodium Bicarbonate) cyanide required to cause death, and when administered together, De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate resulted in a synergistic effect in raising the lethal dose of De Witt's Antacid Tablets (Sodium Bicarbonate) cyanide. The combined therapy appeared to have reduced efficacy when therapy was delayed until signs of poisoning (e.g. convulsions) appeared; however, other investigators have reported survival in dogs that were administered antidotal treatment after respiratory arrest had occurred.

Animal studies conducted in other species (e.g., rat, guinea pig, sheep, pigeon and cat) have also supported a synergistic effect of intravenous De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate in the treatment of cyanide poisoning.

While intravenous injection of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite and De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate was effective in reversing the effects of lethal doses of cyanide in dogs, intramuscular injection of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite, with or without De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate, was found not to be effective in the same setting.

14 CLINICAL STUDIES

The human data supporting the use of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite for cyanide poisoning consists primarily of published case reports. There are no randomized controlled clinical trials. Nearly all the human data describing the use of De Witt's Antacid Tablets (Sodium Bicarbonate) thiosulfate report its use in conjunction with De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite. Dosing recommendations for humans have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

There have been no human studies to prospectively and systematically evaluate the safety of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite in humans. Available human safety information is based largely on anecdotal case reports and case series of limited scope.

16 HOW SUPPLIED/STORAGE AND HANDLING

Each De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite carton (NDC 60267-311-10) consists of the following:

  • One 10 mL glass vial of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite injection 30 mg/mL (containing 300 mg of De Witt's Antacid Tablets (Sodium Bicarbonate) nitrite);

Storage

Store at controlled room temperature between 20°C and 25°C (68°F to 77°F); excursions permitted from 15 to 30°C (59 to 86°F). Protect from direct light. Do not freeze.

(Note: De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate must be obtained separately.)

17 PATIENT COUNSELING INFORMATION

De Witt's Antacid Tablets Nitrite Injection is indicated for acute cyanide poisoning that is judged to be life-threatening and in this setting, patients will likely be unresponsive or may have difficulty in comprehending counseling information.

17.1 Hypotension and Methemoglobin Formation

When feasible, patients should be informed of the possibility of life-threatening hypotension and methemoglobin formation.

17.2 Monitoring

Where feasible, patients should be informed of the need for close monitoring of blood pressure and oxygenation.

Manufactured by Cangene BioPharma, Inc., Baltimore, Maryland 21230 for

Hope Pharmaceuticals, Scottsdale, Arizona 85260

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

NDC 60267-311-10

Rx Only

De Witt's Antacid Tablets (Sodium Bicarbonate) Nitrite

Injection, USP

300 mg/10 mL

(30 mg/mL)

FOR INTRAVENOUS USE

SINGLE USE ONLY

Any unused portion of a vial

should be discarded.

Use with

De Witt's Antacid Tablets (Sodium Bicarbonate) Thiosulfate

for Treatment of

Cyanide Poisoning

Manufactured by

CANGENE bioPharma, Inc.

Baltimore, MD for

HOPE

PHARMACEUTICALS®

Scottsdale, AZ 85260 U.S.A.

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

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References

  1. Dailymed."ALUMINUM HYDROXIDE LIQUID [ATLANTIC BIOLOGICALS CORPS]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  2. Dailymed."SODIUM BICARBONATE TABLET [RUGBY LABORATORIES, INC.]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  3. Dailymed."D-CAL (CALCIUM CARBONATE) TABLET, CHEWABLE [A&Z PHARMACEUTICAL INC.]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).

Frequently asked Questions

Can i drive or operate heavy machine after consuming De Witt's Antacid Tablets?

Depending on the reaction of the De Witt's Antacid Tablets after taken, if you are feeling dizziness, drowsiness or any weakness as a reaction on your body, Then consider De Witt's Antacid Tablets 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 De Witt's Antacid Tablets 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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