Intravenous N-acetylcysteine for preventing contrast-induced nephropathy: a randomised trial.

BACKGROUND: Studies evaluating the role of N-acetylcysteine in patients undergoing coronary angiography have yielded inconsistent data. Less is known about patients with normal renal function at baseline.

METHODS: Prospective, double-blind, placebo-controlled trial to determine the benefits of intravenous N-acetylcysteine as an adjunct to hydration in this kind of population. Patients were randomly assigned to receive either N-acetylcysteine (600 mg twice daily) or placebo, in addition to 0.45% intravenous saline. The primary end point was development of contrast-induced nephropathy, defined as an acute increase in the serum creatinine concentration > or = 0.5 mg/dl and/or > 25% increase above baseline level at 48 h after contrast dosing.

RESULTS: A total of 216 patients were studied: N-acetylcysteine = 107 and placebo = 109. Treatment groups were similar with respect to baseline clinical characteristics. Overall incidence of contrast-induced nephropathy was 10.2%, 10.3% in the N-acetylcysteine group and 10.1% in the placebo group. Furthermore, no significant differences were observed when considering the non-diabetic population, although there was a trend towards a protective effect of N-acetylcysteine in the subgroup of 47 patients with both hypertension and diabetes. There were no significant changes in serum urea nitrogen concentrations. The incidence of in-hospital adverse clinical events was low: no patient with contrast-induced nephropathy required dialysis, the median Coronary Unit stay was 4.5 vs. 4 days, and the mortality rate was 2.8% vs. 4.6% in the N-acetylcysteine and placebo groups, respectively (p=NS).

CONCLUSIONS: The prophylactic administration of intravenous N-acetylcysteine provides no additional benefit to saline hydration in high-risk coronary patients with normal renal function.