Background: Argatroban is a direct thrombin inhibitor approved for the prophylaxis or treatment of thrombosis in patients with heparininduced thrombocytopenia (HIT). The product monograph does not guide clinicians beyond specifying the initial dose of 2 µg/kg per minute (or 0.5 µg/kg per minute for patients with hepatic impairment). Some authors have suggested that in the intensive care unit (ICU) and for patients with acute cardiac disease and those with renal or hepatic dysfunction, this dose may result in a supratherapeutic activated partial thromboplastin time (aPTT).