H2-RECEPTOR ANTAGONISTS AND WARFARIN AND OTHER ORAL ANTICOAGULANTS
The anticoagulant effects of warfarin can be increased by cimetidine. Severe bleeding has occurred in a few patients but some show no interaction at all. Acenocoumarol and phenindione seem to interact similarly.
Monitor the INR if cimetidine is added or withdrawn. The interaction is rapid and may occur within days and even as early as after 24 hours. Famotidine, nizatidine and ranitidine usually appear to be non-interacting alternatives, although isolated cases of bleeding have been seen.
Monitor the INR if cimetidine is added or withdrawn. The interaction is rapid and may occur within days and even as early as after 24 hours. Famotidine, nizatidine and ranitidine usually appear to be non-interacting alternatives, although isolated cases of bleeding have been seen.