Stanozolol is a synthetic anabolic steroid derived from dihydrotestosterone. It is indicated prophylactically to decrease the frequency and severity of attacks of angioedema. In rare cases, serious and even fatal cases of liver problems have developed during treatment with stanozolol. Anabolic steroids may increase sensitivity to anticoagulants; therefore, dosage of an anticoagulant may have to be decreased in order to maintain the prothrombin time at the desired therapeutic level.