NSAIDs increase bleeding by decreasing the activity of blood platelets and therefore formation of blood clots. When used with other drugs that also increase bleeding, for example, warfarin (Coumadin), the likelihood of bleeding complications is increased.

How do NSAIDs cause GI bleeding?

By blocking the Cox-1 enzyme and disrupting the production of prostaglandins in the stomach, NSAIDs can cause ulcers and bleeding. Some NSAIDs have less effect on prostaglandins in the stomach than others, and, therefore, may have a lower risk of causing ulcers, but the increased risk of ulcers still exists.

How do NSAIDs increase risk of bleeding?

Aspirin and nonaspirin nonsteroidal antiinflammatory drugs (NSAIDs) inhibit platelet cyclooxygenase, thereby blocking the formation of thromboxane A2. These drugs produce a systemic bleeding tendency by impairing thromboxane-dependent platelet aggregation and consequently prolonging the bleeding time.