Over 1000 patients each in the acetylcysteine and placebo groups, this study showed exactly equal 12.7% chance of acute kidney injury resulting from contrast exposure during cardiac catheterization. In addition, the 30-day mortality was nearly identical at 2.2% for acetylcysteine and 2.3% for placebo, and only 3 patients in each group required dialysis within 30 days.
Perplexingly enough, the only advantage acetylcysteine had was a lower incidence in adverse effects versus placebo, 2.2% vs. 1.3%. They do not mention what formulation their placebo formulation was, but apparently it caused more nausea & vomiting.
The authors also do a mini meta-analysis to evaluate why previous studies showed a benefit, and they additionally find that studies that had appropriately blinded allocation showed identical outcomes while patients with inadequate blinding demonstrated an acetylcysteine advantage.
"Acetylcysteine for Prevention of Renal Outcomes in Patients Undergoing Coronary and Peripheral Vascular Angiography."