Warfarin-induced life-threatening bleeding associated with a CYP3A4 loss-of-function mutation in an acute limb ischemia patient: Case report and review of the literature.

Patients with acute limb ischemia, deep venous thrombosis and pulmonary artery embolism may be treated with warfarin. The dose-response interaction of warfarin is associated with numerous factors, depending on which an uncommon life-threatening bleeding may occur. The present case study reported on a patient with acute limb ischemia and a history of warfarin-induced bleeding ten years previously and who again developed life threatening bleeding associated with warfarin treatment and received vascular surgery. In this patient, a cytochrome P450 3A4 loss-of-function mutation decreased the effective dose of warfarin. Although this was a rare case, clinicians should be alert to the bleeding risk associated with such rare genetic mutations.