Pharmacist involvement with warfarin dosing for inpatients

Abstract

This study audits the quality of medical inpatient maintenance anticoagulation control by junior doctors and evaluates the impact of the implementation of warfarin guidelines on the anticoagulation control achieved by doctors compared with that by a pharmacist. Introduction of warfarin guidelines made no significant difference to the anticoagulation control achieved by junior doctors. The pharmacist demonstrated significantly better (p < 0.001) therapeutic control than the doctors in the areas of anticoagulation control measured, namely international Normalised Ratios (INRs) less than two and greater than six and INRs within the therapeutic range. The pharmacist overall, maintained 58% of INRs within range compared to 15% by junior doctors, over a twelve week period. In addition, there was a major reduction in the number of INRs requested by the pharmacist. Extrapolated over a year, this would amount to approximately 3,500 fewer INR requests on the medical wards. The effect of pharmacist dosing was also demonstrated in the difference in timing of warfarin administration by nursing staff. A much larger percentage of doses (90%) was administered within one hour of the prescribed time, compared to junior doctors (15%). This study has demonstrated that there is a role for the clinical pharmacist dosing warfarin for inpatients, by offering improved anticoagulation control, in addition to the accepted role in outpatients. It also shows that such involvement provides improved quality of patient care, reduced number of INR requests and improvement in the coordination of patient discharge between primary and secondary care.