N-acetylcysteine effect on serum creatinine and cystatin C levels in CKD patients.

BACKGROUND AND OBJECTIVES N-acetylcysteine (NAC) has been widely used as a prophylactic therapy for contrast-induced nephropathy (CIN). Its efficacy is controversial because of heterogeneity in study results and because of evidence that NAC can alter serum creatinine levels without affecting glomerular filtration rate. This confounding effect of N-acetylcysteine on serum creatinine has not been rigorously tested, however, in a population at risk for CIN and following doses of NAC currently recommended for prophylaxis of CIN. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS "Double-dose" NAC was administered in the absence of iodinated contrast media to 29 stage 3 to 5 stable chronic kidney disease patients. Serum creatinine and cystatin C were measured before and 4 h and 48 h after the last dose of NAC. RESULTS There was no effect of NAC on either serum creatinine or cystatin C levels. CONCLUSION NAC, in doses currently recommended for prophylaxis of CIN, has no effect on serum creatinine or cystatin C levels. It is therefore unlikely that the heterogeneity seen in clinical trials of NAC prophylaxis for CIN is related to a confounding effect on serum creatinine.