Laboratory Monitoring of Non–Vitamin K Antagonist Oral Anticoagulant Use in Patients With Atrial Fibrillation

Abstract

Robust evidence from patients with atrial fibrillation randomized to NOACs or warfarin demonstrates that unmonitored NOAC therapy is at least as effective and safe as monitored warfarin, with lower rates of intracranial hemorrhage and reduced mortality. Further research is required to determine whether routine laboratory monitoring might provide a net benefit for patients. Until such data are available, clinicians should continue to prescribe NOACs in fixed doses without routine monitoring.

Rivaroxaban Precision Dosing Strategy for Real‐World Atrial Fibrillation Patients

“…25,[34][35][36] This is remarkable in that DOAC changes in drug plasma concentration produce an instantaneous change in PT or partial thromboplastin time. [11][12][13] The DOACs all gained market approval for stroke prevention in AF patients with dosing based on phenotype compared with warfarin doses, which must be adjusted to an international normalized ratio in the therapeutic range of 2-3. 19 Each DOAC was found to be at least noninferior to warfarin for efficacy and safety even though there is evidence for individual drug differences (i.e., superiority for dabigatran 150 mg for stroke reduction, apixaban superiority for less major bleeding).…”

“…Rivaroxaban inhibits Factor Xa in a concentration-dependent manner so that the degree of anticoagulation (i.e., prothrombin time (PT)) directly mirrors rivaroxaban plasma concentrations as they rise and fall after oral administration. [11][12][13] The dosage regimen approved by both the FDA and the European Medicines Agency is 20 mg once daily in patients with creatinine clearance (CrCl) >50 ml/min and 15 mg once daily in patients with CrCl between 15 and 50 ml/min. 10,14 Like all DOACs, rivaroxaban has the advantage of dosage simplicity over warfarin because there is no need for international normalized ratio laboratory testing and feedback-based dosing.…”

Switching among oral anticoagulants: is it logical?

“…They have some advantages compared with VKAs, like fixed dose and predictable effects (i.e. no need for monitoring) 3 .…”

Precision drug dosing: A major opportunity for patients and pharmacists

“…According to current recommendations, both patients should receive the same dose of apixaban, dabigatran, or rivaroxaban. However, given that under‐ or over‐dosing of the direct oral anticoagulants creates an increased risk of death or severe morbidity from either stroke or bleeding, special consideration should be given to whether individualized doses would be safer and provide greater therapeutic benefit. Commonly, real‐world patient (RWP) characteristics are not represented in pivotal Phase 3 clinical trials because they are either ineligible or difficult to recruit.…”