Safety and effectiveness outcomes of an inpatient collaborative drug therapy management service for direct thrombin inhibitors

Abstract

The impact of a collaborative drug therapy management (CDTM) agreement enabling pharmacist-managed direct thrombin inhibitor (DTI) therapy was evaluated. A retrospective chart review was conducted to compare selected outcome measures between cohorts of adults who received argatroban or bivalirudin therapy for suspected heparin-induced thrombocytopenia (HIT) before (n = 25) and after (n = 25) the implementation of an institutional DTI protocol under which properly trained and credentialed pharmacists have a primary role in dosing and monitoring DTI infusions. The primary endpoints were the mean time to attainment of activated partial thromboplastin time (aPTT) values in a specified therapeutic range and the proportion of total inpatient treatment time during which aPTT values were in that range. Secondary endpoints included the incidence of major and minor bleeding and the incidence of medication errors. After implementation of the DTI protocol, therapeutic aPTT values were achieved more rapidly (a mean of 3.4 hours in the postimplementation cohort versus a mean of 7.7 hours in the preimplementation cohort, p = 0.009) and maintained more consistently. Rates of bleeding and overall mortality were similar in the two groups; the frequencies of documented medication errors were 12% and 40% in the postimplementation and preimplementation cohorts, respectively (p = 0.05). A pharmacist-driven DTI program resulted in improved effectiveness and safety outcomes, as demonstrated by improved attainment of target aPTT values and a decreased frequency of medication errors.