COMPARISON OF 2 METHODS FOR INR DETERMINATION IN A PHARMACIST-BASED ORAL ANTICOAGULATION CLINIC

Warfarin is a commonly used oral anticoagulant that is usually initiat ed after the definitive diagnosis of a certain thromboembolic disorder or disease. Warfarin therapy will usually be prescribed for 6-12 week s or more, and some patients may continue therapy throughout life, dep ending on the type of thromboembolic disorder. Major problems associat ed with warfarin therapy include adverse effects such as bleeding comp lications and drug-drug or drug-food interactions. In addition, thromb oembolic complications may occur due to subtherapeutic dosages of warf arin. The laboratory reference standards for monitoring warfarin thera py are the prothrombin time (PT) and the International Normalized Rati o (INR). While both the PT or INR will reflect the clinical response i n the patient, results reported as INR values have been shown to be mo re accurate than those reported as PT values. Thirty-two patients were enrolled in this study. Our objectives were to compare INR values mea sured by both the Coumatrak and conventional laboratory method, and to demonstrate the effects of pharmacist intervention on managing patien ts receiving warfarin therapy. Results from our study reveal that INR monitoring by Coumatrak is similar to the conventional laboratory meth od. In addition, our study indicates that patients receiving warfarin therapy can be monitored and managed effectively by pharmacists.