rivaroxaban and ibuprofen

Pharmacodynamic interaction: ibuprofen inhibits cyclooxygenase-1 (COX-1), reducing thromboxane A2 synthesis, impairing platelet aggregation and vasoconstriction. This additive antiplatelet effect combines with rivaroxaban's direct factor Xa inhibition, prolonging bleeding time. Additionally, ibuprofen can cause gastric mucosal injury, increasing the risk of gastrointestinal bleeding.

Co-administration significantly increases the risk of major bleeding, particularly gastrointestinal bleeding, but also intracranial and other bleeding events. The risk is further elevated in patients with renal impairment or advanced age. Patients may present with occult or overt bleeding, delayed bleeding, or prolonged bleeding from minor trauma.

Avoid concurrent use when possible. If combination is necessary, use the lowest effective dose of ibuprofen for the shortest duration. Consider alternative analgesics like paracetamol. Prescribe a proton pump inhibitor for gastroprotection. Monitor patient for signs of bleeding, including haemoglobin, melaena, or unexplained bruising. Advise patient to seek immediate medical attention if bleeding occurs.

Well-established interaction supported by pharmacological mechanisms, pharmacokinetic studies, and clinical trials. Guidelines recommend caution when prescribing NSAIDs to patients on anticoagulants.