Anisindione (brand name Miradon) is a synthetic anticoagulant and an indanedione derivative with action similar to these of Warfarin. It is indicated for the prophylaxis and treatment of venous thrombosis and its extension, the treatment of atrial fibrillation with embolization, the prophylaxis and treatment of pulmonary embolism, and as an adjunct in the treatment of coronary occlusion. Anisindione prevents the formation of active procoagulation factors II, VII, IX, and X, as well as the anticoagulant proteins C and S, in the liver by inhibiting the vitamin K–mediated gamma-carboxylation of precursor proteins. Hemorrhage and/or necrosis are among the hazards of treatment with any anticoagulant and are the main serious complications of therapy. Drugs that have been reported to diminish oral anticoagulant response, ie, decreased prothrombin time response, in man significantly include: adrenocortical steroids; alcohol; antacids; antihistamines; barbiturates and others.