About thiamazole
Thionamide antithyroid medicine
Used for
- Treats hyperthyroidism, including Graves’ disease.
- Used before thyroid surgery or radioactive iodine treatment.
- Injection may be used when oral treatment is not possible.
Usual adult dose
Usually 10–40 mg by mouth daily, adjusted to thyroid tests; injectable dosing varies by product and setting.
Usual dose in children
Usually 0.2–0.5 mg/kg by mouth daily, adjusted by a specialist; injection is not routinely used.
Common side effects
- Rash, itching, or joint pain
- Nausea or stomach upset
- Low white blood cells, rarely causing serious infection
- Liver injury, rarely
Important warnings
- Seek urgent care for fever or sore throat; these may signal dangerously low white blood cells.
- Stop treatment and seek urgent assessment for jaundice, dark urine, or severe abdominal pain.
- Can cause hypothyroidism; thyroid blood tests are needed during treatment.
- Use injectable formulations only under medical supervision; formulations and dosing differ.
Pregnancy
Can harm the unborn baby, especially early in pregnancy. Carbimazole or methimazole may be avoided in the first trimester when alternatives are suitable.
Breastfeeding
Small amounts enter breast milk; low-dose treatment is generally considered compatible with breastfeeding under clinical monitoring.
Interactions
- Warfarin: thyroid changes and treatment may alter anticoagulant effect.
- Theophylline, digoxin, and beta-blockers: doses may need adjustment as thyroid function changes.
- Other medicines that suppress bone marrow may increase blood-cell risks.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.