Strategies to Enable a Stable Warfarin Maintenance Dose

Gandara E, Wells P S.  Strategies to Enable a Stable Warfarin Maintenance Dose.  Journal of Coagulation Disorders, July 2010; 2(2):  63-69


REVIEW ARTICLE


Esteban Gandara^1,2 and Philip S Wells^1,2

Affiliations: ¹Thrombosis Program, Department of Medicine, Division of Hematology, University of Ottawa, Ottawa, Ontario, Canada and ²Ottawa Hospital Research Institute, Ottawa, Ottawa, Ontario, Canada


ABSTRACT

    In North America, warfarin is the current standard for oral anticoagulation therapy in the treatment and/or prophylaxis of different thrombotic conditions. In daily clinical practice a significant proportion of patients on long-term warfarin therapy fail to stabilize within their target therapeutic range leading to a resultant increased risk of either thrombotic events or major bleeding. There are many different strategies that have been advocated to improve International Normalized Ratio (INR)[AQ2] control and enable prediction of, or increase probability of, stable maintenance doses of warfarin. These include: knowledge of the genetic polymorphisms that effect warfarin pharmocokinetics, incorporation of these polymorphisms into dosing algorithms, clinically derived dosing algorithms (so-called nomograms), use of computer software as dosing aids, anticoagulation clinics as the model of care, self-monitoring and dosing, supplementation with Vitamin K, better patient education, and increased frequency of monitoring. Some have tested in multiple studies and have proven effective whereas the utility of others is still under investigation. To conclude, there are several strategies proven to increase the time patients spend in therapeutic INR range. In this review we discuss these strategies and their practical applications.

Keywords: warfarin, maintenance dose, randomized trials, evidence-based, venous thromboembolism

Correspondence: Philip S Wells, The Ottawa Hospital, General Campus, LM 12, Box 206, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada. Tel: 613 737 8755; Fax: 613 737 8851.[AQ3]