Major
Amiodarone × Rivaroxaban
Class III antiarrhythmics (Vaughan Williams)×Direct oral anticoagulants (factor Xa inhibitors)
Mechanism
Amiodarone moderately blocks CYP3A4 and P-glycoprotein – two rivaroxaban clearance routes. Rivaroxaban plasma levels rise by about 50%; bleeding risk rises moderately.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, black stools, blood in urine. Severe cases include gastrointestinal or intracranial haemorrhage.
Management
The combination is acceptable in patients with preserved renal function (creatinine clearance above 50 mL/min) and atrial fibrillation. In renal impairment, switch to warfarin or apixaban.