About propylthiouracil
Thionamide antithyroid medicine
Used for
- Treats overactive thyroid (hyperthyroidism), including Graves’ disease.
- Used before thyroid surgery or radioactive iodine treatment.
- May be used for thyroid storm in hospital.
Usual adult dose
Usually 100–150 mg three times daily initially; reduced as thyroid levels improve. Thyroid storm requires specialist dosing.
Usual dose in children
Usually 5–7 mg/kg daily in three divided doses; specialist supervision is required.
Common side effects
- Rash, itching, or joint pain
- Nausea or stomach upset
- Low white blood cell count
- Liver injury, rarely severe
Important warnings
- Stop and seek urgent assessment for fever, sore throat, or mouth ulcers; these may signal dangerously low white blood cells.
- Seek urgent care for yellow skin, dark urine, severe abdominal pain, or unusual tiredness; liver injury can be severe.
- Rarely causes vasculitis or serious bleeding problems.
- Not usually preferred over methimazole because of liver injury risk; often reserved for specific situations.
Pregnancy
Can cause fetal harm. Methimazole is usually preferred after the first trimester; propylthiouracil may be used early in pregnancy when needed.
Breastfeeding
Generally considered compatible at prescribed doses; use the lowest effective dose and monitor the infant’s thyroid function.
Interactions
- Warfarin: thyroid changes and treatment may alter anticoagulant effect; monitoring may be needed.
- Theophylline, digoxin, and beta-blockers: changing thyroid levels may alter their effects or dose requirements.
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 It may be incomplete or out of date.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.