• Evaluation of Anticoagulation Parameters After Discontinuation of Argatroban in Critically Ill Patients.

      Erstad, Brian; Patanwala, Asad; Gerfen, Ashlee; Jiang, Manfei; Erstad, Brian; Patanwala, Asad; Gerfen, Ashlee; College of Pharmacy, The University of Arizona (The University of Arizona., 2015)
      Objectives: Argatroban is the current drug of choice for type II heparin induced thrombocytopenia. Primarily metabolized by the liver, this direct thrombin inhibitor has a volume of distribution of approximately 174 mLs per kg. While few studies suggested no differences in coagulation parameters or clinical outcomes between obese and non-obese populations receiving argatroban, a recent case report revealed elevated anticoagulation parameters for 20 days post argatroban discontinuation in a morbidly obese female. The purpose of this study is to assess anticoagulation parameters in obese and non-obese patients in an intensive care unit (ICU) setting who received argatroban treatment during their stay. Methods: This is a retrospective, observational, single-centered study. Participants of the study must be adults, at least 18 years of age. Patient must be an inpatient and have received argatroban for either suspected or confirmed heparin-induced thrombocytopenia (HIT). All patients in the study were screened for the above criteria between November 2008 and September 2013. Patients admitted to the cardiac ICU were excluded from the study. Main anticoagulation parameters post discontinuation evaluated were daily international normalized ratio (INR) and activated partial thromboplastin time (aPTT), while safety outcomes included major, minor and non-bleed events. All data were analyzed with STATA 13 with P less than 0.05 being considered as statistically significant. Results: The study included a total of 51 patients, 37 were non-obese with body mass index (BMI) less than 30 kg per m2 (73 percent), and 14 were obese with BMI greater or equal to 30 kg per m2 (27 percent). Among basic demographic data, no differences were found between age, sex, race, height and SOFA scores at baseline between the two groups, BMI less than 30 kg per m2 and BMI greater or equal to 30 kg per m2. (P equals 0.7, 0.21, 1.0, 0.41, 0.51 respectively). However, as expected, weight was the only characteristic that was different at baseline (P less than 0.01). Primary outcome of time of INR to normalization post argatroban administration (2.73 seconds plus or minus 0.27 seconds) as well as safety outcomes including major, minor, and non-bleed adverse events (P equals 0.61) were statistically non-significant between the two groups. Conclusions: In this retrospective, observational, single centered study, no differences were identified between non-obese and obese groups in terms of argatroban administration, primary anticoagulation parameters, and safety outcomes. The length of time required for coagulation parameters to normalize after discontinuation of argatroban therapy for HIT does not appear to be influenced by BMI. Large, multicenter, and random controlled trials are needed to evaluate obesity on pharmacokinetic parameters and clinical outcomes of argatroban.