Radiocontrast dye is commonly used in hospitals for diagnostic and imaging procedures. Following these procedures, some patients have experienced marked elevations in serum creatinine and acute renal failure. Acetylcysteine has been studied as an option for protecting the kidneys during diagnostic procedures that use contrast dye.
Contrast Dye in Diagnostic Procedures
Certain diagnostic tests including angiographs and computed tomography require the use of contrast dye. As radiocontrast dye is injected into the bloodstream or other fluid pathway, imaging machines can track the flow of fluid in organs, tissues or blood vessels. In many cases, abnormalities in fluid flow, including obstructions and divergent pathways, can be detected.
Contrast Dye and Kidney Failure
Contrast dye is the third leading cause of hospital associated acute renal failure. As a result, patients may experience extended hospital stays and unwanted health outcomes. Although the mechanism of kidney damage is likely multi-factorial, renal injury is primarily believed to be a result of oxidative stress and renal ischemia. Contrast dye contains free radicals that are directly toxic to kidney cells. In addition, free radicals may also affect the dilation and constriction of blood vessels resulting in impaired blood flow to the kidneys. An increase in the serum creatinine following procedures with contrast dye may be an indicative of acute kidney failure.
Acetylcysteine and Kidney Protection
Available as both an injectable solution as well as an inhaled solution that can also be taken orally, N-acetylcysteine is a modified version of the amino acid cysteine. Researchers believe that acetylcysteine scavenges free radicals found in contrast dye. In addition, acetylcysteine may also have a dilating effect on blood vessels, thereby increasing blood flow to the kidneys. Intravenous injection and inhaled acetylcysteine solution given orally have both been studied in the protection of kidneys against contrast dye.
Acetylcysteine Benefits Kidneys
In a 2007 study published in Nephrology Dialysis Transplantation titled “Renal Effects of N-Acetylcysteine In Patients at Risk for Contrast Nephropathy: Decrease in Oxidant Stress-Mediated Renal Tubular Injury,” Luciano Drager and colleagues found that patients had significantly better renal function when given acetylcysteine, twice daily for four consecutive days starting 48 hours before the administration of contrast dye, when compared with patients given placebo.
To maximize the protective effects, acetylcysteine is usually given in combination with intravenous fluids for hydration. Since acetylcysteine is relatively inexpensive and seldom causes adverse effects, it may be increasingly useful in the protection of kidneys during procedures requiring radiocontrast dye.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice
References:
1. CMAJ. “Nephropathy Induced by Contrast Media: Pathogenesis, Risk Factors and Preventive Strategies" (accessed November 26, 2010).
2. Journal of the American Society of Nephrology. “N-Acetylcysteine in the Prevention of Radiocontrast-Induced Nephropathy" (accessed November 26, 2010).
3. Oxford Journals. "Renal Effects of N-acetylcysteine In Patients at Risk for Contrast Nephropathy: Decrease in Oxidant Stress-Mediated Renal Tubular Injury" (accessed November 26, 2010).
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