Alternative to Warfarin Prevents Strokes but Causes Excess Bleeding

In patients with nonvalvular atrial fibrillation, vitamin K antagonists (principally warfarin) lower the incidence of stroke, but their use is limited by risk for bleeding and the requirement for frequent monitoring of coagulation parameters. Various alternative anticoagulants that might be less risky and simpler to use are being studied. One such candidate is idraparinux, an inhibitor of activated factor X that can be administered subcutaneously once weekly without coagulation monitoring.

In a multinational industry-supported trial, investigators randomized 4576 patients to receive either subcutaneous idraparinux (2.5 mg once weekly) or an oral vitamin K antagonist adjusted to achieve an INR of 2 to 3. Although idraparinux was statistically…