Clinical evaluation of nafamstat mesilate (FUT 175). A new anticoagulant for plasmapheresis.

Nafamstat mesilate (FUT), a new anticoagulant with a short half-life of biologic activity, was used in six patients who had a history of bleeding (two from the eye, two nasally, and two orally) during plasmapheresis (PP) due to overdosage of heparin. FUT (1.2 mg/kg/hr) was injected into the arterial blood line during PP. Prothrombin time (PT), activated partial thromboplastin time (APTT), bleeding time (BT), and complete blood count (CBC) were measured before and after PP. Values of PT (17 +/- 1.4 sec) after treatment were nearly 1.5 times the levels of PT (12.5 +/- 0.8 sec) before treatment. Levels of APTT after PP (70.4 +/- 4.1 sec) were nearly double the values of APTT before PP (36.8 +/- 2.6 sec). There were no significant differences between red blood cell (RBC), hemoglobin (Hgb), or platelet counts before and after PP. No patient developed thrombosis, hemorrhage, or other side effect during PP. In conclusion, the optimal dosage of FUT was 1.2 mg/kg body weight/hr during PP. FUT is recommended as a useful anticoagulant during PP treatment of patients with an increased risk of bleeding.