Indications for Propylthiouracil:
Give in 3 equally divided doses every 8hrs. Initially 300mg/day. Severe conditions: initially 400mg/day; max 900mg/day. Maintenance: 100–150mg/day.
Give in 3 equally divided doses every 8hrs. <6yrs: not recommended. ≥6yrs: initially 50mg/day; may upward titrate based on response, TSH, and free T4 levels.
Hepatic reactions (eg, severe liver injury, acute liver failure) including cases that require liver transplantation.
Should be reserved for those intolerant to methimazole and in whom radioactive iodine therapy or surgery are not appropriate treatments. Risk of severe liver injury and acute liver failure. Monitor for signs of hepatic dysfunction esp. in the 1st 6 months of therapy; discontinue if occur and obtain LFTs and ALT/AST levels. Discontinue if agranulocytosis, aplastic anemia, ANCA-positive vasculitis, hepatitis, interstitial pneumonitis, fever, or exfoliative dermatitis is suspected. Monitor thyroid function periodically, prothrombin time esp. before surgical procedures. Pregnancy (Cat.D). Nursing mothers.
May potentiate anticoagulants. Caution with other drugs that may cause agranulocytosis. May need to reduce doses of beta-blockers, digitalis glycosides, theophylline at euthyroid state.
Rash, urticaria, GI upset, arthralgia, paresthesia, taste loss/perversion, hair loss, myalgia, headache, drowsiness, neuritis, edema, vertigo, jaundice; blood dycrasias, lupus-like syndrome, drug fever, hepatitis, periarteritis, hypoprothrombinemia, bleeding.