Clinical information
Common uses
- Graves' disease hyperthyroidism
- toxic multinodular goitre when surgery or radioiodine unsuitable
- controlling symptoms before thyroid surgery or radioiodine
Common side effects
- rash and itching
- nausea, vomiting, stomach upset
- joint or muscle aches
- headache, drowsiness
- hair loss, taste loss
Cautions
- report fever or sore throat at once — dangerous white-cell drop
- rare liver inflammation and vasculitis
- first-trimester use linked to birth defects
Interactions
- warfarin and oral anticoagulants (effect increased — extra INR checks)
- beta-blockers (dose may need lowering as thyroid normalises)
- digoxin (levels may rise)
- theophylline (levels may rise)
Pregnancy: avoid in first trimester — birth defect risk; specialist care
Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, methimazole tablet label, setid b53f84ac-4263-478c-883d-aca7ab44fef5 (accessed 2026-08-16)