ibuprofen and apixaban

Pharmacodynamic interaction. Apixaban, a direct factor Xa inhibitor, reduces thrombin generation and thereby impairs clot formation. Ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), inhibits cyclo-oxygenase (COX)-1 and COX-2, decreasing platelet thromboxane A2 production and platelet aggregation. Ibuprofen also causes gastric mucosal injury and can impair renal function, further increasing the risk of bleeding when combined with an anticoagulant. The result is additive impairment of haemostasis and an increased tendency to bleed.

Concurrent use increases the risk of clinically significant bleeding, including gastrointestinal haemorrhage, intracranial bleeding, and bleeding from other sites. The risk is exacerbated in patients with additional risk factors such as advanced age, renal impairment, or a history of peptic ulcer disease. The effect is most pronounced with long-term NSAID use but can occur with short courses.

Avoid co-prescription where possible. If an NSAID is required, use the lowest effective dose for the shortest duration and consider a gastroprotective agent such as a proton pump inhibitor. If combined, monitor for signs of bleeding (melena, haematemesis, bruising, anaemia) and assess haemoglobin and renal function periodically. For patients with a high bleeding risk, consider alternative analgesics such as paracetamol or a weak opioid.

Well established by clinical guidelines and observational studies. The interaction is widely accepted and documented in product labels and regulatory warnings.