Get your patient on Methimazole - Methimazole tablet (Methimazole)

Methimazole tablets, USP are indicated:

• In patients with Graves’ disease with hyperthyroidism or toxic multinodular goiter for whom surgery or radioactive iodine therapy is not an appropriate treatment option.
• To ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy.

Methimazole tablets, USP are 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 mg 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 mg 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.

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

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. There have been postmarketing case reports of acute pancreatitis.

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.

There are reports of a vasculitis, often associated with the presence of anti-neutrophilic cytoplasmic antibodies (ANCA), resulting in severe complications (see WARNINGS ).

Methimazole, 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 mg or 10 mg (43.8 mcmol or 87.6 mcmol) methimazole USP, an orally administered antithyroid drug.

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

The molecular weight is 114.16, and the molecular formula is C ₄ H ₆ N ₂ S. The structural formula is as follows:

Methimazole 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.

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

Methimazole Tablets, USP, for oral administration, are available as

5 mg

White, round scored tablet, de-bossed with "CE" over "36" on one side and functional score on the other side and supplied as:

NDC 62135-205-30 bottles of 30

NDC 62135-205-90 bottles of 90

NDC 62135-205-01 bottles of 100

NDC 62135-205-18 bottles of 180

NDC 62135-205-05 bottles of 500

10 mg

White, round scored tablet, de-bossed with "CE" over "37" on one side and functional score on the other side and supplied as:

NDC 62135-206-30 bottles of 30

NDC 62135-206-90 bottles of 90

NDC 62135-206-01 bottles of 100

NDC 62135-206-18 bottles of 180