UMEM Educational Pearls

Title: Nail in the NAC Coffin for Prevention of Contrast-Induced Nephropathy

Category: Pharmacology & Therapeutics

Keywords: contrast-induced nephropathy, n-acetylcysteine, NAC (PubMed Search)

Posted: 10/31/2013 by Bryan Hayes, PharmD (Updated: 11/2/2013)
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A recent meta-analysis has called into question whether contrast-induced AKI even occurs after an IV dye load for radiologic imaging. [1] This conclusion is most certainly up for debate.

Irrespective of that conclusion, prevention of contrast-induced nephropathy is still important. Is there any benefit to using N-acetylcysteine over normal saline in the ED? Probably not according to a new study. [2]

The primary outcome was contrast-induced nephropathy, defined as an increase in creatinine level of 25% or 0.5 mg/dL, measured 48 to 72 hours after CT.
The authors found no reduction in contrast-induced nephropathy in patients who received NAC vs normal saline (about 7% in each group).
The important finding is that the contrast-induced nephropathy rate in patients receiving less than 1 L IV fluids in the ED was 13% compared to 3% for more than 1 L.

Conclusions

Contrast-induced AKI does happen after emergency CT.
NAC does not provide additional benefit over saline alone.
Giving more than 1 L of normal saline markedly reduces the risk.

References

McDonald JS, et al. Frequency of acute kidney injury following intravenous contrast medium administration: a systematic reviews and meta-analysis. Radiology 2013;267(1):119-28. [PMID 23319662]
Traub SJ, et al. N-acetylcysteine plus intravenous fluids versus intravenous fluids alone to prevent contrast-induced nephropathy in emergency computed tomography. Ann Emerg Med 2013;62(5):511-20. [PMID 23769807]

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