Out of various agents studied, it was the only one found to prevent contrast-induced nephropathy


A recent meta-analysis supports administration of N-acetylcysteine prophylaxis to prevent contrast-induced nephropathy, especially in high-risk patients. Researchers also noted that the drug is inexpensive and readily available, and has few side effects.

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“Our meta-analysis demonstrates  that N-acetylcysteine is the most effective agent for preventing contrast-induced nephropathy in patients with chronic renal insufficiency,” the researchers wrote in Annals of Internal Medicine (2008;148:284-294). “Whether this risk reduction translates into a benefit in clinical outcomes remains to be proven.”


A team led by Aine M. Kelly, MD, MS, of the University of Michigan Hospitals in Ann Arbor, analyzed data from 41 randomized trials involving 6,379 patients who had elective radiographic procedures in which contrast agents were used. The researchers found that N-acetylcysteine reduced the risk of contrast-induced nephropathy by 38% compared with the use of saline alone.


Another drug, theophylline, did not significantly decrease the risk and a third agent, furosemide, increased the risk more than threefold. N-acetylcysteine costs only 23 cents for a 500-mg tablet (priced as of Jan. 17 at www.shopping.com), Dr. Kelly’s group noted. Other agents found not to have beneficial effects include fenoldopam and mannitol.


Contrast-induced nephropathy is defined as an increase in serum creatinine greater than 25% within three days of intravascular contrast administration in the absence of an alternative cause.

“The results of this meta-analysis should be evaluated in head-to-head empirical studies of active agents to identify the most efficacious regimen for preventing contrast-induced nephropathy,” the authors concluded.


“Our findings indicate that the use of such oral agents as N-acetylcysteine is reasonable in high-risk patients who are to receive large or repeated volumes of contrast agents. We believe that the lack of significant side effects and the low cost justifies use of these agents while empirical data on clinical outcomes mature.”


Hydration and iso-osmolar or low-osmolar contrast agents such as iodixanol are all associated with a decreased incidence of contrast-induced nephropathy in patients with renal impairment, Dr. Kelly’s group observed.


They cited a meta-analysis showing that although low-osmolar contrast agents decreased the risk for contrast-induced nephropathy by two thirds, they did not completely eliminate the risk. “Thus, protective agents must still be considered for patients with severe renal impairment who are to receive large volumes of contrast agents,” the investigators noted.