Medical and economic consequences of a blinded oral anticoagulant brand change at a municipal hospital.

In 1980, the Boston City Hospital pharmacy made a bulk purchase of a brand of warfarin sodium that was different from the brand previously stocked. The physician and nurse in charge of the anticoagulation clinic and responsible for regulating patient dosage of warfarin were not aware of the change in warfarin brand. During the period of brand substitution, we observed an increase in the number of patients whose anticoagulation was poorly controlled. There was a concomitant increase in the number of clinic visits and an increased frequency of prothrombin time testing to regulate the dosage in such patients. We performed a retrospective analysis of the medical and economic consequences of the change in brand of warfarin. Our results show that a significant increase in morbidity and overall health care costs resulted from this attempt to economize by changing brands of medication in our municipal hospital setting.