What is the rationale for using N-acetylcysteine (NAC) in the treatment of non-acetaminophen-related liver failure (NALF)?

A 2009 RCT study (1) involving adults with NALF (including many due to drug toxicity, HBV, and autoimmune causes) found longer transplant-free survival (not overall survival) in the treatment group, especially in those with lower grade encephalopathy, or liver failure caused by drugs or HBV.  How NAC might work in this setting (e.g. effect on microcirculation/02 delivery through interference with cytokines) is not clear but a cool article (2) recently reported lower serum levels of interleukin-17 among treated patients.  Fascinating!  

1.Bass S, Zook N. Intravenous acetylcysteine for indications other than acetaminophen overdose. Am J Health-Syst Pharm 2013;70:1496-1501.

2.Stravitz RT, Sanyal AJ, Reisch J, et al. Effects of N-acetylcysteine on cytokines in non-acetaminophen acute liver failure: potential mechanism of improvement in transplant-free survival. Liver Int. 2013;33:1324-1331.

What is the rationale for using N-acetylcysteine (NAC) in the treatment of non-acetaminophen-related liver failure (NALF)?

How should follow-up serum C-reactive protein (CRP) in patients with community-acquired pneumonia (CAP) be interpreted?

I look for the CRP level to drop to less than one-half of its value on admission after a couple of days of antibiotic therapy, since CRP half-life is less than a day following zero order elimination kinetics.  Of interest, in a study of serial CRP in severe CAP (1), a CRP ratio >0.5 by day 3 was associated with non-resolving pneumonia ( sensitivity 91%, specificity 55%)   performing significantly better than body temperature or WBC count.   So if there is any doubt about how a patient is doing clinically, a repeat CRP looking for a drop of greater than on-half after 3-4 days of therapy may be helpful.

1. Coelho L, Povoa P, Almenda E, et al. Usefulness of C-reactive protein in monitoring the severe community-acquired pneumonia clinical course.  Critical Care 2007;11:R92

 


 

How should follow-up serum C-reactive protein (CRP) in patients with community-acquired pneumonia (CAP) be interpreted?