The following are 10 points to remember from this guide to the use of dabigatran, rivaroxaban, and apixaban, the new oral anticoagulants (NOACs):
1. Renal function should be assessed on a regular basis because all NOACs require dose reductions depending on renal function.
2. The activated partial thromboplastin time provides a qualitative (but not quantitative) indicator of the presence of dabigatran, a direct thrombin inhibitor.
3. The prothrombin time provides a qualitative indicator of the presence of rivaroxaban and apixaban, factor Xa inhibitors.
4. Quantitative laboratory tests for determining the degree of anticoagulation in patients taking NOACs are not readily available.
5. Rivaroxaban should be taken with food while the other NOACs can be taken with or without food.
6. The dosage of dabigatran should be reduced to 75 mg twice daily in patients taking dronedarone, ketoconazole, or itraconazole.
7. Treatment with a NOAC is contraindicated or not recommended in patients taking ritonavir, rifampin, or phenytoin.
8. Because the anticoagulant effects of NOACs dissipate rapidly 12-24 hours after a dose, warfarin may be preferable to a NOAC in patients in whom low compliance is suspected.
9. If excellent compliance in taking a NOAC as prescribed for ≥3 weeks prior to transthoracic cardioversion cannot be confirmed, a transesophageal echocardiogram should be performed to rule out atrial thrombus.
10. In patients with normal renal function, the NOACs should be held for ≥24 hours before an elective surgical procedure associated with a minor bleeding risk, and for ≥48 hours before surgical procedures associated with a major bleeding risk.
Fred Morady, M.D., F.A.C.C. (Disclosure)
Arrhythmias, Afib, General Cardiology, Anticoagulation Management