Direct-Acting Oral Anticoagulants- Pharmacist
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.
Wewill 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.