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Abstract

Introduction: Dabigatran (Pradaxa®) is an oral direct thrombin inhibitor Food and Drug Administration (FDA) approved to prevent stroke and systemic embolism in nonvalvular atrial fibrillation. The purpose of this study is to examine prescribing patterns of dabigatran in a large teaching hospital and determine if we are meeting FDA approved guidelines for use. We also aim to examine bleeding incidence and the affect on bleeding assays. Hypothesis: We hypothesize that use of dabigatran is appropriate as indicated by the FDA label and incidence of bleeding will be as described in the package insert, around 6%. Methods: This was a medication use evaluation looking at 38 consecutive patients prescribed dabigatran during hospital admission. Parameters monitored included prescribing physician, dose prescribed, indication for use, and renal function. Further we evaluated the incidence of bleeding in these patients, the affect on measured INR and aPTT, and lastly pharmacist intervention on inappropriate use or dosing. The primary outcomes were incidence of appropriate use and dosing, incidence of bleeding, and the affect on INR and aPTT. Results: Demographics of patients in this study were an average age of 78, evenly male and female and 76% Caucasian. Prescribing was equally divided between housestaff, hospitalists, and cardiologist. Only 87% of patients were prescribed dabigatran for the FDA labeled indication of nonvalvular atrial fibrillation. Pharmacists intervened on 80% of patients prescribed dabigatran for the inappropriate indication as well as dose adjusted dabigatran for 24% of the prescribed dosages. The incidence of gastrointestinal (GI) bleeding with dabigatran was 10.5%. 74% of patients had an aPTT above the upper limit of normal and 64% had an INR above the upper limit of normal. Conclusions: Clinicians need to be aware of the appropriate use and renal dosing of dabigatran to prevent patient harm. The incidence of GI bleeding appears to be higher than reported in the package insert. Lastly, dabigatran does affect aPTT and INR, and these may be useful to determine medication adherence but not to determine the level of anticoagulation.