Presented at the North American Congress of Clinical Toxicology, Toronto, Ontario, Canada, 2008.
The In Vitro Effect of N-Acetylcysteine on Prothrombin Time in Plasma Samples From Healthy Subjects
Article first published online: 15 APR 2011
© 2011 by the Society for Academic Emergency Medicine
Academic Emergency Medicine
Volume 18, Issue 4, pages 351–354, April 2011
How to Cite
Pizon, A. F., Jang, D. H. and Wang, H. E. (2011), The In Vitro Effect of N-Acetylcysteine on Prothrombin Time in Plasma Samples From Healthy Subjects. Academic Emergency Medicine, 18: 351–354. doi: 10.1111/j.1553-2712.2011.01041.x
The authors have no relevant financial information or potential conflicts of interest to disclose.
Supervising Editor: Richard Sinert, DO.
A related commentary appears on page 428.
- Issue published online: 15 APR 2011
- Article first published online: 15 APR 2011
- Received September 22, 2010; revision received October 26, 2010; accepted October 26, 2010.
ACADEMIC EMERGENCY MEDICINE 2011; 18:351–354 © 2011 by the Society for Academic Emergency Medicine
Objectives: In the treatment of acetaminophen toxicity, clinicians believe that N-acetylcysteine (NAC) artificially elevates prothrombin time (PT), potentially obscuring signs of liver damage. However, the effect of NAC on human blood coagulation remains unverified. The purpose of this study was to evaluate the effect of NAC on PT prolongation in human plasma.
Methods: The authors obtained blood samples from 33 volunteer subjects. The blood plasma samples were divided into four 1-mL aliquots. The first aliquot was used as a control. To three additional aliquots, varying amounts of NAC were added, maintaining constant volume with a maximum dilution of 0.5%. The four concentrations of NAC (control, 250, 500, or 1,000 mg/L) were incubated at 37°C for 1 hour, and PT was measured. PT values were compared using fixed effects regression.
Results: Mean (± standard deviation [SD]) PT values for the control, 100, 500, and 1,000 mg/L NAC values were 13.9 (±1.01), 14.2 (±1.08), 15.5 (±1.21), and 17.4 (±1.72) seconds, respectively. At the 1,000 mg/L concentration, two PTs exceeded 22 seconds, and half exceeded 17 seconds. PT increased with NAC concentrations (fixed effects regression p < 0.001) in a dose-dependent manner.
Conclusions: In this in vitro human model, NAC had a dose-dependent effect on PT.