COLESTYRAMINE AND RELATED DRUGS AND WARFARIN AND OTHER ORAL ANTICOAGULANTS

The anticoagulant effects of phenprocoumon and warfarin can be reduced by colestyramine. An isolated and unexplained report describes a paradoxical increase in the effects of warfarin.
Colestyramine given 3 to 6 hours after warfarin has been shown to minimise this interaction. Colestipol does not appear to interact with either warfarin or phenprocoumon and so may be a suitable alternative. However, note that it is usually recommended that other drugs are given one hour before or 4 hours after colestipol and one hour before or 4 to 6 hours after colestyramine.