Background and hypothesis: Several studies have utilized low-dose regimens of N-acetylcysteine (NAC) for 48 hours to prevent contrast-induced nephropathy (CIN) after cardiac catheterization (cath) and percutaneous coronary intervention (PCI). A lengthy pretreatment period with NAC may not be feasible in urgent situations. The purpose of this study was to assess the efficacy of an abbreviated, higher dose regimen of NAC for the prevention of CIN after elective and urgent coronary angiography (cath) and/or percutaneous coronary intervention (PCI).

Methods: We prospectively evaluated 80 patients referred for elective or urgent cath and/or PCI with stable chronic renal insufficiency (creatinine clearance <50 cc/min). Patients were randomized to: NAC 1000 mg PO 1 hour before cath/PCI and 4 hours later, or placebo. All patients received hydration (0.9% saline) before and after cath/PCI (minimum total volume ≥1500 mL). CIN was defined as an increase of Cr ≥0.5 mg/dL or ≥25% 48 hours after cath/PCI.

Results: CIN occurred in 3 of 36 (8%) patients of the NAC group vs. 11of 44 (25%) in the placebo group (P = 0.051; OR 3.7, 95% CI 0.94–14.4). Serum creatinine (mean ± SD) remained stable in the NAC group after cath/PCI (2.02 ± 0.56 vs. 2.10 ± 0.81 mg/dL; P = 0.34), but increased after cath/PCI in the placebo group (1.93 ± 0.53 vs. 2.10 ± 0.74 mg/dL; P < 0.01).

Conclusions: An abbreviated, higher dose regimen of NAC prevents the rise of serum creatinine 48 hours after cath/PCI, and may prevent CIN after cath/PCI. (J Interven Cardiol 2004;17:159–165)