Major
Amiodarone × Dabigatran
Class III antiarrhythmics (Vaughan Williams)×Direct thrombin inhibitor
Mechanism
Amiodarone blocks intestinal P-glycoprotein – the main route of dabigatran absorption and elimination. Dabigatran plasma levels rise by 30–60%; bleeding risk increases.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, black stools, blood in urine. Risk is higher in renal impairment.
Management
With creatinine clearance above 50 mL/min, standard dabigatran 150 mg twice daily is acceptable. At clearance 30–50 mL/min, reduce to 110 mg twice daily. Below 30 mL/min, do not prescribe the combination; switch to warfarin or apixaban.