Drug Interaction Report

MONITOR CLOSELY: The coadministration of clopidogrel with naproxen resulted in occult gastrointestinal blood loss in healthy volunteers. The mechanism has not been described, but may be due to additive platelet inhibition. The coadministration of nonsteroidal anti-inflammatory drugs (NSAIDs) and clopidogrel should be undertaken with extreme caution. Additionally, some NSAIDs are substrates for the CYP450 isoenzyme 2C9. Clopidogrel inhibits this isoenzyme and therefore may lead to decreased metabolism of these NSAIDs. The clinical magnitude of this interaction is not known.

MANAGEMENT: Close observation for increased NSAID toxicity is recommended if these agents are coadministered with clopidogrel. Patients should also be advised to promptly report any signs of GI bleeding to their caregiver, including pain, swelling, dizziness, weakness, bloody or coffee-ground emesis, or red or black stools, and to avoid any over-the-counter NSAID products.