Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Methimazole (thiamazole) is the most used antithyroid medicine: it blocks thyroid peroxidase, so the thyroid makes less hormone. It is used for hyperthyroidism, including Graves' disease, before thyroid surgery or radioactive iodine, and long term. Carbimazole is a prodrug that turns into it. It is sold as Tapazole and Thyrozol, among other names.
Methimazole is broken down in the liver. Its rare serious side effect, agranulocytosis, has been linked in genome-wide studies to the immune-system gene versions HLA-B*38:02 and HLA-DRB1*08:03, mainly in East Asian populations, which the gene study listed concerns. The findings are not used to guide treatment, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Methimazole. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
HLA-B HLA-B*38:02: Level 3. Toxicity: Graves Disease. 2.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Antithyroid Drugs (class) (Antithyroid Agents)
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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