THE INFLUENCE OF N-ACETYLCYSTEINE ON THE MEASUREMENT OF PROTHROMBIN TIME AND ACTIVATED PARTIAL THROMBOPLASTIN TIME IN HEALTHY-SUBJECTS

The purpose of the study was to evaluate whether the infusion of N-ace tylcysteine decreased the measurement of prothrombin time and activate d partial thromboplastin time (APTT) in healthy persons. N-acetylcyste ine was administered intraveneously 10 mg kg(-1) as a loading dose and then at a rate of 10 mg kg(-1) h-1 for 32 h in six male subjects. The intrinsic, extrinsic and common pathway of coagulation were monitored with activated partial thromboplastin time (APTT), and prothrombin ti me, respectively. In addition, the extrinsic coagulation pathway was m onitored with the clotting activity of single factors II, VII, and X. No effect on the intrinsic coagulation pathway was observed. There was a significant and rapid decrease in prothrombin time. Coagulation fac tors II, VII and X, the three components of prothrombin time, decrease d significantly to different degrees. We conclude that infusion of N-a cetylcysteine intraveneously decreases the prothrombin time in healthy subjects. Thus, one should not make conclusions which are too far-rea ching based on prothrombin time alone in patients who have been treate d recently with N-acetylcysteine intraveneously.