Phenprocoumon Colestipol

The anticoagulant effects of phenprocoumon and warfarin can be reduced by colestyramine, especially if the coumarin is given at the same time. An isolated report describes unexpected sensitivity to warfarin in a patient taking colestyramine, which was attributed to a possible reduction in vitamin K absorption with colestyramine. Colestipol did not alter the absorption or effect of phenprocoumon or warfarin and colesevelam did not alter the pharmacokinetics of warfarin. 

In a placebo-controlled, single-dose study in 4 healthy subjects, phenprocoumon plasma levels and the prothrombin response were unaffected by colestipol 8 g given at the same time as phenprocoumon 12 mg. Similarly, in an study quoted in a review, the concurrent use of eolestipol 10 g did not cause any changes in the absorption of a single 10-mg dose of warfarin in healthy subjects. 

No special precautions appear necessary if warfarin or phenprocoumon and colestipol or colesevelam are given concurrently. 

Harvengt C, Desager JP. Effects of colestipol, a new bile acid sequestiant, on the absexption of phenprocoumon in man. EurJ Clin Pharmacol (1973) 6,19-21. 

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