Apixaban: An orally active factor Xa inhibitor to prevent strokes and systemic embolism in patients with nonvalvular atrial fibrillation

Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia in the United States, and it increases the risk of stroke by about 5-fold. Stroke can result in substantial morbidity and mortality. It decreases patients' quality of life and results in increased healthcare costs. Warfarin is effective for stroke prevention in patients with AF, but it has several drawbacks, including pharmacokinetic and pharmacogenomic interactions and the necessity of frequent laboratory monitoring. Consequently, there is a need for new anticoagulant agents that are effective, safe, and convenient to use. Apixiban (Eliquis) is an orally active factor Xa inhibitor. Its manufacturers are seeking FDA approval to market apixaban to reduce risk of stroke and systemic embolism in patients with nonvalvular AF (NVAF). In the AVERROES trial, apixaban reduced the rate of stroke or systemic embolism compared with aspirin in patients with NVAF who were unwilling to take warfarin or deemed unsuitable for it, and apixaban was not associated with an increased risk of major bleeding. In the ARISTOTLE trial, patients with NVAF and at least 1 other risk factor for stroke, who took apixaban 5 mg twice daily, had fewer primary efficacy events (stroke or systemic embolism), a lower rate of major bleeding (including intracranial hemorrhage), and decreased all-cause mortality compared with those receiving adjusted-dose warfarin. Apixaban is a substrate for CYP3A4 and P-glycoprotein, so the potential for drug-drug interactions exists. (Formulary. 2012;47:180-183.)