ORLISTAT AND WARFARIN AND OTHER ORAL ANTICOAGULANTS

Several cases of increased INR have been reported in patients taking either warfarin or acenocoumarol after also taking orlistat. In contrast, a study in healthy subjects found no interaction. The manufacturers suggest that an interaction between orlistat and anticoagulants is possible.
Close monitoring is recommended for the first 4 weeks of concurrent use. As changes in diet are known to affect anticoagulant levels this seems prudent.