Direct-Acting Oral Anticoagulants- Pharmacy Technician
For more than 50 years, vitamin K antagonists such as warfarin were the only oral anticoagulation option for patients with blood clotting disorders. Dabigatran (Pradaxa®), an oral direct thrombin (factor IIa) inhibitor, finally broke onto the scene with FDA approval in October 2010 as the first of the next generation of oral anticoagulants. Since that time, 3 additional oral anticoagulants have been approved in the US. Rivaroxaban (Xarelto®), apixaban (Eliquis®), and the very recently approved edoxaban (SavaysaTM) are oral direct factor Xa inhibitors that share the convenient attributes of dabigatran: fixed dosing, no routine coagulation monitoring (eg, INR testing), and no known dietary interactions – to name just a few. This issue will review the evidence supporting these next generation oral anticoagulants and their place in therapy for atrial fibrillation (AF), acute treatment and long-term secondary prevention of deep vein thrombosis (DVT) and pulmonary embolism (PE), and DVT and PE prophylaxis after major orthopedic surgery. The differences between the agents will be highlighted, as well as comparisons with warfarin for conditions where both are indicated. Educational and counseling tips for pharmacists and other community-based providers will be presented. Finally, limitations and challenges to the use of the next generation oral anticoagulants will be discussed. Before we begin, here’s a word on nomenclature. Early on, this next generation of oral anticoagulants was convincingly called NOACs (Novel Oral AntiCoagulants), but these drugs would not be novel forever. An Institute For Safe Medication Practices (ISMP) safety alert noted that “NoAC” was interpreted as “no anticoagulation” in a patient at high risk of stroke. The ISMP has designated “NoAC” a potentially dangerous abbreviation and discourages its use. The acronym DOAC for Direct-Acting Oral Anticoagulant provides a reasonably short, easily pronounced, accurately descriptive abbreviation that distinguishes the class from warfarin, which acts indirectly.8 We will use the term DOAC throughout this issue; but be aware that other acronyms (eg, TSOAC [target-specific oral anticoagulant]) are also found in the literature and may work their way into clinical practice.