MILAN, ITALY. Contrast agents (x-ray dyes) are widely used in CT scanning and procedures involving heart catheterization (angiography, ablation and angioplasty). Contrast agents contain large amounts of iodine and can be very hard on the kidneys. Italian researchers now confirm that N-acetylcysteine (NAC), a powerful free radical scavenger, is effective in preventing contrast agent-induced kidney failure in patients with compromised kidney function (serum creatinine concentration of 1.5 mg/dL or greater and creatinine clearance less than 60 mL/min). Their clinical trial involved 192 patients scheduled for coronary or peripheral angiography or angioplasty. Half the patients were randomized to receive the drug fenoldopam mesylate prior to the procedure and the other half received 1200 mg of NAC on the day before and on the day of the procedure accompanied by saline infusion for 12 hours before and 12 hours after the procedure if left ventricular ejection fraction was less than 40%.
Only 4 of 97 patients (4.1%) assigned to NAC experienced kidney toxicity as compared to 13 of 95 patients
(13.7%) in the fenoldopam group. No side effects were observed in the NAC group, but 4 patients in the
fenoldopam group did experience adverse effects; one of those died from renal failure. The researchers
conclude that NAC is more effective than fenoldopam.
Editor's comment: Contrast agents presumably are hard on the kidneys – and perhaps the thyroid gland – whether or not you already have a compromised kidney function. Thus, supplementing with NAC for a couple of days prior to the procedure, the day of the procedure, and 2 days after may be a prudent measure for those scheduled to undergo elective heart catheterization procedures or CT scans.