What medications can interact with cranberry supplements?

Cranberry is considered safe with almost all medications. In medicinal doses it may increase the effect of anti-coagulation drugs like warfarin (Coumadin), causing bleeding. People on medication for diabetes should beware of sugar-sweetened cranberry juice; cranberries are naturally quite tart and their juice usually has some kind of sweetener. Finally, note that cranberry juice is acidic, like orange juice, and as such may counteract the effectiveness of antacid drugs.