Prescription medicine
Methimazole First approved as Tapazole
Methimazole (Tapazole) is a prescription medicine with an FDA approval on record since 1950. FDA's NDC Directory lists it from 21 generic labelers, and pharmacies paid $0.0702 per methimazole 5 mg tablet in the October 7, 2026 NADAC survey.
- Generic listed
Check it at the source: the methimazole FDA label on DailyMed (effective August 20, 2026, AiPing Pharmaceutical, Inc.); the NDA 7517 record on Drugs@FDA; every methimazole label on DailyMed.
Highlights of the record
FDA label of August 20, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026; NADAC October 7, 2026
Used for
From the label: indications and usageMethimazole tablets 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.
Forms and strengths
- 5 mg
- 10 mg
Tablet.
On the market
- Earliest approval on file
- June 21, 1950 Tapazole, King Pharms; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 11 first March 29, 2000; 8 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 21 of which 21 under generic applications, 0 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- $0.0702 per tablet Methimazole 5 mg tablet
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 7,805 through July 30, 2026
What is methimazole used for?
From the label: indications and usageMethimazole tablets 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.
FDA pharmacologic class: Thyroid Hormone Synthesis Inhibitor.
Source: FDA drug label (Methimazole), AiPing Pharmaceutical, Inc., effective August 20, 2026 (SPL set 06bb4bcc-5e47-48b6-a76c-648f846704e8), via openFDA; the full label on DailyMed
Is there a generic for methimazole (Tapazole)?
The FDA approved the first generic methimazole on March 29, 2000. 11 generic applications are approved; 8 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists methimazole from 21 labelers under a generic (ANDA) application. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
- 1950 earliest approval on file
- 2000 first generic approved
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What do pharmacies pay for methimazole (Tapazole)?
In CMS's NADAC survey of October 7, 2026, pharmacies paid $0.0702 per Methimazole 5 mg tablet, down 18% from $0.0861 on October 8, 2025. The chart's scale runs from the lowest to the highest price shown, not from zero. NADAC is what retail pharmacies paid their wholesalers, per unit, in CMS's monthly survey; what a patient pays depends on insurance and the pharmacy.
- Methimazole 5 mg tablet (generic)
| Strength and form | Brand or generic | Pharmacy cost | 30 tablets, or one pen or vial | 12-month change |
|---|---|---|---|---|
| Methimazole 10 mg tablet | Generic | $0.117 per tablet | $3.51 | -9% |
| Methimazole 5 mg tablet | Generic | $0.0702 per tablet | $2.11 | -18% |
Source: CMS National Average Drug Acquisition Cost (NADAC) survey, October 7, 2026: what retail pharmacies paid per unit; not a counter price
What does the methimazole label say about other medicines?
The methimazole label names 3 other medicines in its interaction, contraindication or warning sections. The labels of 5 other medicines name methimazole. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Propylthiouracil | warnings | Liver Toxicity Although there have been reports of hepatotoxicity (including acute liver failure) associated with methimazole, the risk of hepatotoxicity appears to be less with methimazole than with propylthiouracil, especially in the pediatric population. |
| Theophylline | drug interactions | Theophylline: Theophylline clearance may decrease when hyperthyroid patients on a stable theophylline regimen become euthyroid; a reduced dose of theophylline may be needed. |
| Warfarin | drug interactions | Drug Interactions 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. ß-adrenergic blocking agents: |
Source: FDA drug label (Methimazole), AiPing Pharmaceutical, Inc., effective August 20, 2026 (SPL set 06bb4bcc-5e47-48b6-a76c-648f846704e8), via openFDA; the full label on DailyMed
What do FAERS reports show for methimazole?
The FDA Adverse Event Reporting System holds 7,805 reports that list methimazole among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 641 are coded as a death and 2,871 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Alternatives to methimazole
- medicines labeled for the same conditions
- Other antithyroid medicines
- the pharmacologic class, with prices and generics
- Methimazole side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other