Abstract

N-Acetylcysteine (NAC) is used in the prevention of contrast-induced nephropathy (CIN) in our institution. The variation in clinical effects as a result of dosage differences between intravenous (IV) and oral administration warrants further investigation. This study primarily aimed to evaluate the incidence of CIN in patients with renal impairment, comparing those who received IV NAC with those receiving oral NAC. This was an observational, retrospective study conducted from 1st January, 2007 to 31st March, 2010. The study included 94 renally impaired patients (baseline glomerular filtration rate (eGFR) < 70 ml/min/1.73 m²) who had undergone iodinated-contrast procedure, and received either IV NAC (150 mg/kg pre-procedure, then 50 mg/kg post-procedure) or oral NAC (600 mg twice daily for one day before the procedure, then for two days after the procedure). The changes in serum creatinine (SCr) over time: pre-procedure, post-procedure 24, 48 and 72 h for both regimens were recorded and analysed. The overall incidence of CIN was 22% in IV NAC group versus 28.0% in the oral group (P = 0.403). CIN was found to be significantly associated with unstable renal function but not route of NAC administration. In patients with stable renal function, the incidence of CIN was 8.3% in the IV group versus 11.9% in the oral group; P = 1.000. In patients with unstable renal function, the incidence of CIN was 46.2 and 42.9% in the IV and oral groups, respectively; P = 0.863. Diabetes mellitus (odds ratio (OR) = 10.704, P = 0.018) and unstable renal status (OR = 6.800, P = 0.015) were the independent predictors of CIN by multivariate analysis. Both IV and oral NAC had comparable effects on the incidence of CIN in patients with stable renal status. However, both routes of NAC administration were less effective in preventing CIN in patients with unstable renal status.

Key words: N-acetylcysteine, iodinated contrast-induced nephropathy, computed tomography angiography procedures, unstable renal function, renal impairment.