Potentiation of anticoagulant response to warfarin by sulphinpyrazone: a double-blind study in patients with prosthetic heart valves.

The effect of Sulphinpyrazone on the anticoagulant response to Warfarin was evaluated by a double-blind study in 11 patients with prosthetic heart valves. Six patients received Warfarin and Sulphinpyrazone and 5 Warfarin and placebo. Sulphinpyrazone potentiated the anticoagulant effect of Warfarin. Patients receiving Sulphinpyrazone needed about half the amount of Warfarin as compared to the control group. There were four bleeding episodes in the Sulphinpyrazone group and one episode in the control group. It was difficult to regulate the dose of Warfarin in patients also receiving Sulphinpyrazone.