Methimazole is a thyroid hormone synthesis inhibitor sold in the U.S. under 2 brand and generic names, for goiter and thyroid crisis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
From the FDA label for Methimazole (application ANDA040547). Other methimazole products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Methimazole tablets 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 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 ½ of the initial dose.
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. There are reports of a vasculitis, often associated with the presence of antineutrophilic cytoplasmic antibodies (ANCA), resulting in severe complications [see WARNINGS ] . 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. To report SUSPECTED ADVERSE REACTIONS, contact Upsher-Smith Laboratories, LLC at 1-855-899-9180 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Methimazole tablets are contraindicated in the presence of hypersensitivity to the drug or any of the other product components.
Anticoagulants (oral) Due to potential inhibition of vitamin K activity by methimazole, 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.
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Typical price | |
|---|---|---|---|---|---|---|---|
| 1 | Not yet rated | Prescription | Tablet | Generic | $2 | View → | |
| 2 | Not yet rated | Prescription | Tablet | Generic | $2 | View → |
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| HP;71 | 10 mg | white | round | — |
| HP;70 | 5 mg | white | round | — |
| VM | 5 mg | white | round | — |
| XM | 10 mg | white | round | — |
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.