rivaroxaban and clarithromycin

Clarithromycin inhibits CYP3A4 and P-glycoprotein, which are the main metabolic and efflux pathways for rivaroxaban. This inhibition increases rivaroxaban plasma concentrations by approximately twofold, enhancing its anticoagulant effect.

The increased rivaroxaban exposure raises the risk of bleeding, including serious events such as intracranial haemorrhage and gastrointestinal bleeding. Patients may present with unexplained bruising, prolonged bleeding from cuts, or blood in urine or stool. This risk is further augmented in patients with renal impairment, older age, or concomitant use of antiplatelet agents.

Avoid co-prescription of rivaroxaban and clarithromycin. If alternative antibiotics are not suitable, monitor patients closely for signs of bleeding, and consider a temporary reduction in rivaroxaban dose or switching to a less interacting antibiotic such as azithromycin or doxycycline. Assess renal function and reassess anticoagulant requirements during therapy.

This interaction is well established through pharmacokinetic studies and is listed in standard drug interaction references and prescribing guidelines. Clinical experience and case reports support the increased bleeding risk.