Table 3:
Drug–Drug Interactions Involving Anticoagulants and Antiarrhythmics
| Antiarrhythmic Drug | Mechanism of Interaction | Warfarin | Dabigatran | Rivaroxaban | Apixaban | Edoxaban | |
|---|---|---|---|---|---|---|---|
| Quinidine | • | Warfarin: 3A4 inhibition | Potentiated anticoagulant effect | 53% increase | Extent of increase unknown | No data yet | 77% increase |
| • | DOACs: P-gp competition | ||||||
| Flecainide | • | None anticipated | None known | No data yet | No data yet | No data yet | No data yet |
| Propafenone | • | Warfarin: 3A4 inhibition | Potentiated anticoagulant effect | No data yet | No data yet | No data yet | No data yet |
| Propranolol | • | Warfarin: 1A2 inhibition | Potentiated anticoagulant effect | No data yet | No data yet | No data yet | No data yet |
| Carvedilol | • | DOACs: P-gp competition | No effect | No data yet | No data yet | No data yet | No data yet |
| Metoprolol | • | None anticipated | None known | No data yet | No data yet | No data yet | No data yet |
| Amiodarone | • | Warfarin: 3A4, 1A2, 2C9 inhibition | Potentiated anticoagulant effect | 12%−60% increase | Minor effect | No data yet | 40% increase |
| • | DOACs: P-gp competition | ||||||
| Dronedarone | • | Warfarin and DOAC: P-gp competition, 3A4 inhibition | Potentiated anticoagulant effect | 70%–100% increase, combination contraindicated | Moderate effect, combination contraindicated | No data yet, caution advised | 85% increase; consider dose adjustment or different DOAC |
| Sotalol | • | None anticipated | None known | No data yet | No data yet | No data yet | No data yet |
| Dofetilide | • | None anticipated | None known | No data yet | No data yet | No data yet | No data yet |
| Verapamil | • | Warfarin: 3A4 inhibition | Potentiated anticoagulant effect | 12%–180% increase (if taken simultaneously); consider dose adjustment or different DOAC | No effect | No data yet | 53% increase |
| • | DOACs: P-gp competition, weak 3A4 inhibition | ||||||
| Diltiazem | • | Warfarin: 3A4 inhibition | Potentiated anticoagulant effect | No effect | No effect | 40% increase | No data yet |
| • | DOACs: P-gp competition, weak 3A4 inhibition | ||||||
DOAC: direct oral anticoagulant; CYP: cytochrome P-450; P-gp: P-glycoprotein.