Severe hepatotoxicity on beginning propylthiouracil therapy.

We report a case of propylthiouracil (PTU)-induced cholestatic hepatotoxicity in Graves' disease that developed 1 day after beginning PTU. After clinical recover, liver abnormalities persisted for 5 years. Percutaneous liver biopsy and the eventual normalization of enzyme levels excluded permanent liver damage as a result of PTU therapy. Thus prolonged elevation of serum enzymes is consistent with the diagnosis of PTU-induced hepatotoxicity, which may recover completely.