Pharmacotherapy
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Review Meta Analysis
Anticoagulation control with daily low-dose vitamin k to reduce clinically adverse outcomes and international normalized ratio variability: a systematic review and meta-analysis.
Difficulties managing warfarin therapy have led to speculation that daily supplementation with a low dose of vitamin K might improve anticoagulation control and clinical outcomes. Thus we sought to review the available medical literature systematically examining the effectiveness of low-dose vitamin K supplementation for the reduction of clinically relevant adverse events due to vitamin K antagonist (VKA) use and for stabilization of the international normalized ratio (INR). ⋯ This meta-analysis, despite the few studies and overall low quality, suggests no beneficial role of low-dose (100 to 200 μg) vitamin K supplementation on the reduction of clinically relevant adverse events in patients taking VKAs, despite a small improvement of the TTR. Data were insufficient, however, from patients with unstable INRs.
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Rivaroxaban is the first agent available within a new class of anticoagulants called direct factor Xa inhibitors. Rivaroxaban is approved for use in the United States for the prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, for the prevention of deep vein thrombosis in patients undergoing total hip replacement and total knee replacement, for the treatment of deep vein thrombosis and pulmonary embolism, and for the reduction in risk of recurrence of deep vein thrombosis and pulmonary embolism (with additional indications under review). Rivaroxaban dose and frequency of administration vary depending on the indication. ⋯ Potential strategies for reversing rivaroxaban's anticoagulant effect are reviewed. Health systems will need to perform a systematic safety evaluation and ensure that numerous hospital policies related to anticoagulation are updated to include rivaroxaban. A comprehensive approach to education is needed for clinicians, patients, and technical support personnel involved in patient interactions to ensure safe use.
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As better international normalized ratio (INR) control and self-testing reduce events in warfarin-treated patients, and vitamin K supplementation may improve INR control, our primary objective was to evaluate the effect of a system combining frequent INR self-testing with online remote monitoring and management (STORM₂) and low-dose vitamin K supplementation on INR control; our secondary objectives were to assess the impact of STORM₂ on clinician time and to evaluate the influence of pharmacogenomics on INR stability and warfarin dose after vitamin K supplementation. ⋯ The 25% point improvement in TTR with STORM₂ is a greater improvement than reported previously with other efforts to improve TTR. STORM₂ required a minimum amount of clinician time. Pharmacogenomics were not predictive of improved INR control or the magnitude of the warfarin dose after vitamin K supplementation, although the content of the product was unreliable. Patients with the GG VKORC1 genotype required a higher warfarin dose than predicted by the product information. The potential clinical impact of improved INR control with this method warrants comparisons with conventionally managed warfarin and with the new oral anticoagulants.