Nonsteroidal anti-inflammatory drugs and aspirin: a comparison of the antiplatelet effects.

Antiplatelet effects of common analgesics were assessed in vitro. The Streck Platelet Aggregation Test Kit (Omaha, NE) was used to measure percent platelet aggregation in response to sodium arachidonate, collagen, adenosine diphosphate, and ristocetin in patients on various analgesics. In comparison with the control group, the response to arachidonate and collagen of ibuprofen (86% vs. 33% and 55% vs. 23%), naproxen (86% vs. 43% and 55% vs. 29%), indomethacin (86% vs. 26% and 55% vs. 17%), and aspirin (86 vs. 21% and 55 vs. 23%) all demonstrated a significant yet comparable reduction in platelet aggregation (p < 0.01). Because of the comparable antiplatelet effects of aspirin and NSAIDs, the additional benefits of daily aspirin in those patients on chronic and consistent NSAID therapy must be reconsidered.