welchol and Anisindione Interactions

Interactions between welchol(colesevelam) and Anisindione (anisindione)

anisindione and colesevelam (Moderate Drug-Drug)

MONITOR: Decreases in International Normalized Ratio (INR) have been reported during postmarketing use of colesevelam in patients receiving warfarin. The mechanism of interaction is unknown. In an in vivo drug interaction study, colesevelam had no effect on warfarin bioavailability during coadministration. However, the study did not evaluate warfarin pharmacodynamics.

MONITOR: Bile acid sequestrants can decrease the absorption of fat-soluble vitamins like vitamin K. No specific studies have been conducted to evaluate potential effects of colesevelam on the absorption of coadministered dietary or supplemental vitamins. In non-clinical safety studies, rats administered colesevelam at doses greater than 30-fold the projected human clinical dose developed hemorrhage in association with vitamin K deficiency.

MANAGEMENT: Patients receiving warfarin and other oral anticoagulants should have their INR monitored before initiating colesevelam and frequently during early colesevelam therapy.