Problems Encountered in Long‐term Treatment with Anticoagulants

Abstract

The course of long-term anticoagulant therapy in 114 outpatients was evaluated over a 3 mo. period. The evaluation was based on the registration of information from the clinical records and from 2 personal interviews with each patient. The patients had attended the Anticoagulation Clinic for 141 wk on the average. The prothrombin complex activity (PP%) level was significantly lower in patients with bleeding episodes. An apparently higher PP% level in patients with thromboembolic manifestations was not significant. No bleeding was observed when the PP% was above 25. Warfarin resulted in relatively fewer bleeding episodes and more PP% values within the desired range (10-25) than phenprocoumon and bishydroxycoumarin. The role of age, but not of moderate hypertension, as a risk factor was confirmed. A probable adverse interaction of the anticoagulant and other drugs was found in 37.5% of the situations in which an interaction could be expected according to the literature.