What is the role of N-acetylcysteine in the prevention of contrast-induced nephropathy (CIN)?

Updated: Feb 21, 2020
  • Author: Anita Basu, MD, FACP; Chief Editor: Vecihi Batuman, MD, FASN  more...
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NAC is acetylated L-cysteine, an amino acid. Its sulfhydryl groups make it an excellent antioxidant and scavenger of free oxygen radicals. It also enhances the vasodilatory properties of nitric oxide.

In a systematic review and meta-analysis of 61 randomized controlled trials that included 11,480 patients, Xu et al determined that NAC supplementation was associated with a significant decrease in CIN risk and blood creatinine level, but not with a reduction in mortality or nephropathy requiring dialysis. In addition, NAC supplementation did not reduce the risk of CIN in patients with diabetes. [49]

Xu et al noted that NAC prophylaxis provides much more important benefit in patients with renal dysfunction and high contrast medium dose than in those with normal renal function and low dose of contrast agent. Their findings also suggested that administering NAC orally provides increased protection against CIN. The authors concluded that, “it is reasonable to administer NAC by the oral route for patients who are undergoing coronary angiography and who have renal dysfunction or who are receiving high doses of contrast agent.” [49]

The standard oral NAC regimen consists of 600 mg twice daily for 24 hours before and on the day of the procedure. Higher doses of 1 g, 1200 mg, and 1500 mg twice daily have also been studied, with no significant dose-related or route-related (oral vs intravenous) difference. NAC has very low oral bioavailability; substantial interpatient variability, and inconsistency between the available oral products, which obscures the picture further. [8, 36, 50]

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