Thyrozol

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Thyrozol uses


DESCRIPTION

Thyrozol® (Methimazole Tablets, USP) (1-methylimidazole-2-thiol) is a white, crystalline substance that is freely soluble in water. It differs chemically from the drugs of the thiouracil series primarily because it has a 5- instead of a 6-membered ring.

Each tablet contains 5 or 10 mg (43.8 or 87.6 µmol) Thyrozol, an orally administered antithyroid drug.

Each tablet also contains lactose monohydrate, magnesium stearate, starch (corn), pregelatinized starch and talc.

The molecular weight is 114.16, and the molecular formula is C4H6N2S. The structural formula is as follows:

Chemical Structure

CLINICAL PHARMACOLOGY

Thyrozol inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. The drug does not inactivate existing thyroxine and tri-iodothyronine that are stored in the thyroid or circulating in the blood nor does it interfere with the effectiveness of thyroid hormones given by mouth or by injection.

Thyrozol is readily absorbed in the gastrointestinal tract, metabolized in the liver, and excreted in the urine.

INDICATIONS AND USAGE

Thyrozol is indicated:

CONTRAINDICATIONS

Thyrozol is contraindicated in the presence of hypersensitivity to the drug or any of the other product components.

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WARNINGS

First Trimester Use of Thyrozol and Congenital Malformations

Thyrozol crosses the placental membranes and can cause fetal harm, when administered in the first trimester of pregnancy. Rare instances of congenital defects, including aplasia cutis, craniofacial malformations, gastrointestinal malformations (esophageal atresia with or without tracheoesophageal fistula), omphalocele and abnormalities of the omphalomesenteric duct have occurred in infants born to mothers who received Thyrozol in the first trimester of pregnancy. If Thyrozol is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be warned of the potential hazard to the fetus.

Because of the risk for congenital malformations associated with use of Thyrozol in the first trimester of pregnancy, it may be appropriate to use other agents in pregnant women requiring treatment for hyperthyroidism. If Thyrozol is used, the lowest possible dose to control the maternal disease should be given.

Agranulocytosis

Agranulocytosis is potentially a life-threatening adverse reaction of Thyrozol therapy. Patients should be instructed to immediately report to their physicians any symptoms suggestive of agranulocytosis, such as fever or sore throat. Leukopenia, thrombocytopenia, and aplastic anemia (pancytopenia) may also occur. The drug should be discontinued in the presence of agranulocytosis, aplastic anemia (pancytopenia), ANCA-positive vasculitis, hepatitis, or exfoliative dermatitis and the patient's bone marrow indices should be monitored.

Liver Toxicity

Although there have been reports of hepatotoxicity associated with Thyrozol, the risk of hepatotoxicity appears to be less with Thyrozol than with propylthiouracil, especially in the pediatric population. Symptoms suggestive of hepatic dysfunction (anorexia, pruritis, right upper quadrant pain, etc.) should prompt evaluation of liver function (bilirubin, alkaline phosphatase) and hepatocellur integrity (ALT, AST). Drug treatment should be discontinued promptly in the event of clinically significant evidence of liver abnormality including hepatic transaminase values exceeding 3 times the upper limit of normal.

Hypothyroidism

Thyrozol can cause hypothyroidism necessitating routine monitoring of TSH and free T4 levels with adjustments in dosing to maintain a euthyroid state. Because the drug readily crosses placental membranes, Thyrozol can cause fetal goiter and cretinism when administered to a pregnant woman. For this reason, it is important that a sufficient, but not excessive, dose be given during pregnancy.

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PRECAUTIONS

General

Patients who receive Thyrozol should be under close surveillance and should be cautioned to report immediately any evidence of illness, particularly sore throat, skin eruptions, fever, headache, or general malaise. In such cases, white-blood-cell and differential counts should be obtained to determine whether agranulocytosis has developed. Particular care should be exercised with patients who are receiving additional drugs known to cause agranulocytosis.

Information for Patients

Patients should be advised that if they become pregnant or intend to become pregnant while taking an antithyroid drug, they should contact their physician immediately about their therapy.

Laboratory Tests

Because Thyrozol may cause hypoprothrombinemia and bleeding, prothrombin time should be monitored during therapy with the drug, especially before surgical procedures. Thyroid function tests should be monitored periodically during therapy. Once clinical evidence of hyperthyroidism has resolved, the finding of a rising serum TSH indicates that a lower maintenance dose of Thyrozol should be employed.

Drug Interactions

Anticoagulants

Due to potential inhibition of vitamin K activity by Thyrozol, the activity of oral anticoagulants (e.g., warfarin) may be increased; additional monitoring of PT/INR should be considered, especially before surgical procedures.

β-adrenergic blocking agents

Hyperthyroidism may cause an increased clearance of beta blockers with a high extraction ratio. A dose reduction of beta-adrenergic blockers may be needed when a hyperthyroid patient becomes euthyroid.

Digitalis glycosides

Serum digitalis levels may be increased when hyperthyroid patients on a stable digitalis glycoside regimen become euthyroid; a reduced dosage of digitalis glycosides may be needed.

Theophylline

Theophylline clearance may decrease when hyperthyroid patients on a stable theophylline regimen become euthyroid; a reduced dose of theophylline may be needed.

Carcinogenesis, Mutagenesis, Impairment of Fertility

In a 2 year study, rats were given Thyrozol at doses of 0.5, 3, and 18 mg/kg/day. These doses were 0.3, 2, and 12 times the 15 mg/day maximum human maintenance dose. Thyroid hyperplasia, adenoma, and carcinoma developed in rats at the two higher doses. The clinical significance of these findings is unclear.

Pregnancy

Pregnancy Category D

See WARNINGS

If Thyrozol is used during the first trimester of pregnancy or if the patient becomes pregnant while taking this drug, the patient should be warned of the potential hazard to the fetus.

In pregnant women with untreated or inadequately treated Graves' disease, there is an increased risk of adverse events of maternal heart failure, spontaneous abortion, preterm birth, stillbirth and fetal or neonatal hyperthyroidism.

Because Thyrozol crosses placental membranes and can induce goiter and cretinism in the developing fetus, hyperthyroidism should be closely monitored in pregnant women and treatment adjusted such that a sufficient, but not excessive, dose be given during pregnancy. In many pregnant women, the thyroid dysfunction diminishes as the pregnancy proceeds; consequently, a reduction of dosage may be possible. In some instances, anti-thyroid therapy can be discontinued several weeks or months before delivery.

Due to the rare occurrence of congenital malformations associated with Thyrozol use, it may be appropriate to use an alternative anti-thyroid medication in pregnant women requiring treatment for hyperthyroidism particularly in the first trimester of pregnancy during organogenesis.

Given the potential maternal adverse effects of propylthiouracil, it may be preferable to switch from propylthiouracil to Thyrozol for the second and third trimesters.

Nursing Mothers

Thyrozol is present in breast milk. However, several studies found no effect on clinical status in nursing infants of mothers taking Thyrozol. A long-term study of 139 thyrotoxic lactating mothers and their infants failed to demonstrate toxicity in infants who are nursed by mothers receiving treatment with Thyrozol. Monitor thyroid function at frequent (weekly or biweekly) intervals.

Pediatric Use

Because of postmarketing reports of severe liver injury in pediatric patient treated with propylthiouracil, Thyrozol is the preferred choice when an antithyroid drug is required for a pediatric patient.

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ADVERSE REACTIONS

Major adverse reactions (which occur with much less frequency than the minor adverse reactions) include inhibition of myelopoieses (agranulocytosis, granulocytopenia, thrombocytopenia, and aplastic anemia), drug fever, a lupus-like syndrome, insulin autoimmune syndrome (which can result in hypoglycemic coma), hepatitis (jaundice may persist for several weeks after discontinuation of the drug), periarteritis, and hypoprothrombinemia. Nephritis occurs very rarely.

Minor adverse reactions include skin rash, urticaria, nausea, vomiting, epigastric distress, arthralgia, paresthesia, loss of taste, abnormal loss of hair, myalgia, headache, pruritus, drowsiness, neuritis, edema, vertigo, skin pigmentation, jaundice, sialadenopathy, and lymphadenopathy.

OVERDOSAGE

Signs and Symptoms

Symptoms may include nausea, vomiting, epigastric distress, headache, fever, joint pain, pruritus, and edema. Aplastic anemia or agranulocytosis may be manifested in hours to days. Less frequent events are hepatitis, nephrotic syndrome, exfoliative dermatitis, neuropathies, and CNS stimulation or depression. No information is available on the median lethal dose of the drug or the concentration of Thyrozol in biologic fluids associated with toxicity and/or death.

Treatment

To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison Control Center. In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in the patient.

In the event of an overdose, appropriate supportive treatment should be initiated as dictated by the patient's medical status.

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DOSAGE AND ADMINISTRATION

Thyrozol is administered orally. The total daily dosage is usually given in 3 divided doses at approximately 8-hour intervals.

Adult

The initial daily dosage is 15 mg for mild hyperthyroidism, 30 to 40 mg for moderately severe hyperthyroidism, and 60 mg for severe hyperthyroidism, divided into 3 doses at 8-hour intervals. The maintenance dosage is 5 to 15 mg daily.

Pediatric

Initially, the daily dosage is 0.4 mg/kg of body weight divided into 3 doses and given at 8-hour intervals. The maintenance dosage is approximately 1/2 of the initial dose.

HOW SUPPLIED

Thyrozol Tablets are available in:

The 5-mg tablets are round, white to off-white, scored on one side and the other side debossed with "J94".

They are available as follows:

Bottles of 100 NDC 60793-104-01

The 10-mg tablets are round, white to off-white, scored on one side and the other side debossed with "J95".

They are available as follows:

Bottles of 100 NDC 60793-105-01

Store at controlled room temperature, 15° to 30°C (59° to 86°F).

Manufactured by: AAI Pharma, 1726 North 23rd St., Wilmington, NC 28405

LAB-0602-2.0

December 2015

Logo

Pfizer

NDC 60793-104-01

Thyrozol ®

Thyrozol Tablets, USP

5 mg

100 TABLETS

Rx only

Pfizer

NDC 60793-105-01

Thyrozol ®

Thyrozol Tablets, USP

10 mg

100 TABLETS

Rx only

Thyrozol 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.


Thyrozol 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.


Thyrozol 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.


Thyrozol 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.


Thyrozol 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."TAPAZOLE (METHIMAZOLE) TABLET [PFIZER LABORATORIES DIV PFIZER INC]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  2. Dailymed."METHIMAZOLE: 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).
  3. "methimazole". https://pubchem.ncbi.nlm.nih.gov/co... (accessed August 28, 2018).

Frequently asked Questions

Can i drive or operate heavy machine after consuming Thyrozol?

Depending on the reaction of the Thyrozol after taken, if you are feeling dizziness, drowsiness or any weakness as a reaction on your body, Then consider Thyrozol 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 Thyrozol 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 Thyrozol, 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 Thyrozol 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.

Visitor reports

Visitor reported useful

No survey data has been collected yet

Two visitors reported side effects

Did you get side effects while taking the Thyrozol drug, or were there no side effects?
According to the survey conducted by website sdrugs.com users, the below-mentioned percentages indicate the number of people experiencing the side effects and the number of people not experiencing the side effects when taking Thyrozol medicine. Every drug produces minimal side effects, and they are negligible most times, when compared to the desired effect [use] of the medicine. Side effects depend on the dose you are taking, any drug interactions that happen when you are on other medications, if the patient is sensitive, and other associated conditions. If you cannot tolerate the side effects, consult your doctor immediately, so he can either adjust the dose or change the medication.
Visitors%
No side effects2
100.0%

Visitor reported price estimates

No survey data has been collected yet

Three visitors reported frequency of use

How often in a day do you take the medicine?
Are you taking the Thyrozol drug as prescribed by the doctor?

Few medications can be taken Once in a day more than prescribed when the doctor's advice mentions the medicine can be taken according to frequency or severity of symptoms. Most times, be very careful and clear about the number of times you are taking the medication. The report of sdrugs.com website users about the frequency of taking the drug Thyrozol is mentioned below.
Visitors%
Once in a day1
33.3%
Twice in a day1
33.3%
3 times in a day1
33.3%

Six visitors reported doses

What is the dose of Thyrozol drug you are taking?
According to the survey conducted among sdrugs.com website users, the maximum number of people are using the following dose 1-5mg. Few medications come in only one or two doses. Few are specific for adult dose and child dose. The dose of the medicine given to the patient depends on the severity of the symptom/disease. There can be dose adjustments made by the doctor, based on the progression of the disease. Follow-up is important.
Visitors%
1-5mg2
33.3%
6-10mg2
33.3%
51-100mg1
16.7%
101-200mg1
16.7%

One visitor reported time for results

What is the time duration Thyrozol drug must be taken for it to be effective or for it to reduce the symptoms?
Most chronic conditions need at least some time so the dose and the drug action gets adjusted to the body to get the desired effect. The stastistics say sdrugs.com website users needed 5 days to notice the result from using Thyrozol drug. The time needed to show improvement in health condition after using the medicine Thyrozol need not be same for all the users. It varies based on other factors.
Visitors%
5 days1
100.0%

Visitor reported administration

No survey data has been collected yet

Three visitors reported age

Visitors%
30-452
66.7%
46-601
33.3%

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The information was verified by Dr. Rachana Salvi, MD Pharmacology

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