Argatroban Dosage Requirements and Outcomes in Intensive Care versus Non‐Intensive Care Patients

Study Objective. To compare the outcomes of reduced‐dose argatroban therapy in patients in the intensive care unit (ICU) with those of non‐ICU patients. Design. Retrospective medical record review. Setting. Large, academic, tertiary care hospital. Patients. Thirty‐eight ICU patients and 43 non‐ICU patients who received the institutional protocol of argatroban 0.8 μg/kg/minute and 1.2 μg/kg/minute, respectively, between March 2004 and September 2005. Measurements and Main Results. Data on patient demographics, argatroban dosing, heparin‐induced thrombocytopenia antibody results, activated partial thromboplastin times (aPTTs), new thrombotic events, and major bleeding events were extracted from medical records. Time‐weighted mean ± SD doses of argatroban were 0.82 ± 0.3 μg/kg/minute for ICU patients and 1.25 ± 0.29 μg/kg/minute for non‐ICU patients. Mean aPTT ratios were similar between groups: 2.07 ± 0.53 for ICU patients and 2.00 ± 0.45 for non‐ICU patients. More than 70% of all aPTT ratios were therapeutic. More than 95% of patients in both groups achieved a therapeutic aPTT ratio during therapy. Fewer ICU patients than non‐ICU patients had all therapeutic aPTT ratios during argatroban therapy (29% vs 51%, p=0.07). Thrombotic events occurred in six (16%) ICU patients versus none of the non‐ICU patients (p=0.009). Thrombotic events occurred in 4 (31%) of the 13 ICU patients with confirmed heparin‐induced thrombocytopenia. Major bleeding occurred in four (11%) ICU patients versus none of the non‐ICU patients (p=0.04). Conclusion. Both ICU and non‐ICU patients require less than the manufacturer‐recommended initial dosage of argatroban. However, ICU patients appear to be at an increased risk for bleeding and thrombotic events despite their attainment of therapeutic aPTTs.