Hereditary warfarin resistance.

We report on a case of hereditary warfarin resistance in a 27-year-old black man. Hereditary warfarin resistance is a rare disorder transmitted as autosomal dominant. It should be suspected in patients who require high doses of warfarin, achieve high plasma warfarin levels, and have a normal plasma warfarin clearance. Treatment includes either high dose warfarin or heparin (subcutaneous).