Non-vitamin K oral anticoagulants (NOACs) are part of a new class of drugs that provide physicians with an alternative to warfarin, a medication with significant bleeding risk. These medications have a therapeutic benefit in patients with non-valvular atrial fibrillation, and include apixaban (Eliquis), dabigatran (Pradaxa), and rivaroxaban (Xarelto). Unlike warfarin, the NOACs do not require routine monitoring of the INR (a measure of clotting time) and have fewer cross-reactions with other drugs/foods. Additionally, warfarin must be given intravenously, and the convenience of administering NOACs per os cannot be overlooked.

With their recent entrance to the market, NOACs are rapidly gaining popularity among physicians and patients. Although they have a safer profile with a smaller risk for adverse events as compared to warfarin, physicians should be sure to proceed with caution prior to prescribing these medications, especially if patients are taking any other prescriptions.

These drug interactions are a large drawback to their usage, and physicians must be made aware of the potential for serious adverse effects. In particular, the cross-reactivity between NOACs and other medications has been well established. Concurrent use of NOACs with drugs such as amiodarone, fluconazole, rifampin, and phenytoin has been associated with an increased risk of major bleeding as compared to the use of NOACs alone. Thus, physicians should consider the potential bleeding risk associated with NOACs and obtain a detailed list of all current medications a patient may be taking before a prescription is given.

Reference: Chang SH, Chou IJ, Yeh YH et al. (2017) Non-Vitamin K Oral Anticoagulants and the Risk of Major Bleeding. JAMA 318(13):1250-1259.