Intravenous N-Acetylcysteine in the Prevention of Contrast Media-Induced Nephropathy

OBJECTIVE: To define the clinical role of intravenous N-acetylcysteine for prophylaxis of contrast-induced nephropathy (GIN). DATA SOURCES: Randomized controlled clinical trials were identified using a search of MEDLINE (1990-September 2010) with the search terms acetylcysteine, N-acetylcysteine, NAC, intravenous, IV, nephropathy, nephrotoxic, radiocontrast, contrast, and media. The search was limited to studies published in English. Additional pertinent literature was retrieved by reviewing references of the articles obtained in the initial search. DATA SYNTHESIS: N-Acetylcysteine is a vasodilator and antioxidant that has been investigated for the prevention of GIN. In the majority of clinical trials, neither oral nor intravenous N-acetylcysteine has demonstrated clinical benefits at preventing GIN. The pharmacodynamic and pharmacokinetic profiles of intravenous N-acetylcysteine are significantly different from those of the oral product in that intravenous administration bypasses extensive first-pass metabolism. Studies have suggested that N-acetylcysteine directly affects serum creatinine levels in a way that is not associated with improvement of kidney function. Only intravenous N-acetylcysteine doses that were higher than the oral doses showed potential benefits, but they were associated with significant adverse events. Furthermore, the study populations were heterogeneous, including patients with various levels of kidney function and other risk factors, and the clinical definition of GIN was not well established. CONCLUSIONS: No conclusive evidence has shown that intravenous N-acetylcysteine is safe and effective in preventing GIN. Further clinical trials to define its role are warranted.