NEW YORK (Reuters Health) – High-dose N-acetylcysteine decreases the incidence of contrast-induced nephropathy, results of a meta-analysis indicate.

“N-acetylcysteine has the advantages of being relatively innocuous, inexpensive, and easy to administer,” Dr. Hariprasad Trivedi, of the Medical College of Wisconsin, Milwaukee, and colleagues note in the September issue of the American Journal of Medicine.

“While prior data regarding use of N-acetylcysteine to prevent contrast-induced nephropathy have been conflicting, our analysis suggests that high-dose therapy with this agent is effective,” Dr. Trivedi added in an email to Reuters Health.

The study team identified 16 reports of randomized trials comparing high-dose N-acetylcysteine versus inactive treatment. High-dose N-acetylcysteine was defined as a daily dose greater than 1200 mg or a single dose greater than 600 mg given within 4 hours of the procedure.

The studies involved a total of 1,677 adults (mean age, 68 years), mostly male (67.8%). Slightly more than a third (38.7%) were diabetic. Among all study participants — 842 randomized to high-dose N-acetylcysteine and 835 to placebo – the weighted mean baseline creatinine was 1.58 mg/dL.

According to Dr. Trivedi and colleagues, the odds of contrast-induced nephropathy were 54% lower in patients randomized to high-dose N-acetylcysteine, compared to those randomized to a control group.

“The analysis “strongly favored high-dose N-acetylcysteine (odds ratio 0.34),” they report.

Cumulative doses in the various studies ranged from 1800 mg to 6000 mg. Dr. Trivedi told Reuters Health, “One regimen we have seen used successfully is 1200 mg given orally two times a day for four doses.”

Dr. Trivedi and colleagues admit, however, that “the appropriate dose remains uncertain except that a dose as defined in the current study decreases the risk of contrast-induced nephropathy.”

“There is a need for further investigation to assess the impact of effective prevention of contrast-mediated renal injury on other outcomes such as the need for dialysis and long-term survival,” Dr. Trivedi added.

Reference:
Am J Med 2009;122:874.e9-874.e15.