Critical
Dabigatran × Dronedarone
Direct thrombin inhibitor×Class III antiarrhythmic
Mechanism
Dronedarone strongly inhibits intestinal P-glycoprotein, the clearance route of dabigatran. Dabigatran plasma levels rise 2-fold or more. FDA Multaq Section 4.3 specifically lists dabigatran etexilate as an absolute contraindication.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage, gross haematuria with renal colic, spontaneous retroperitoneal haematomas. Symptoms may appear within days of co-prescription.
Management
The combination is not prescribed. For atrial fibrillation patients on dronedarone, anticoagulate with warfarin, apixaban, or rivaroxaban (the latter two use P-glycoprotein less and are acceptable without dose change).