Which statement best describes the interaction of NSAIDs with anticoagulants?

• A. They have no interaction with anticoagulants.
• B. They always cancel the effect of anticoagulants.
• C. They decrease bleeding risk.
• D. They can increase bleeding risk and GI irritation; use with caution.

Answer: (D)

The interaction centers on how NSAIDs affect platelets and the stomach lining, adding to the effects of anticoagulants on clotting. NSAIDs inhibit COX-1, which reduces thromboxane A2 and makes platelets less able to aggregate. Anticoagulants slow down the formation of fibrin in the coagulation cascade. Put together, there’s a two‑fold disruption of hemostasis: platelets don’t clump effectively and the coagulation system is dampened, so any bleeding is more likely and can be more prolonged. In addition, NSAIDs irritate the gastric mucosa and can promote ulcers by lowering protective prostaglandins, which raises the risk of gastrointestinal bleeding. When a patient is also on anticoagulants, this GI bleeding risk is even higher. For this reason, use with caution—consider alternatives like acetaminophen for pain, use the lowest effective NSAID dose for the shortest duration if an NSAID is necessary, and monitor for signs of bleeding or GI distress.