In patients undergoing coronary angiography, the incidence of contrast induced nephropathy(CIN)varies widely and ranges from < 5% in the lowest risk patients, to nearly 50% in the highest risk patients. Prior data has shown oral n-acetyl cysteine (NAC) to be effective in reducing the incidence of CIN.Due to extensive first pass metabolism, the bioavailability of oral NAC is poor and ranges from 4%-10%. We hypothesize that the incidence of CIN will be reduced in patients with ACS who undergo PCI by the prophylactic administration of intravenous NAC.

This is a prospective, randomized, double-blind, placebo-controlled single center clinical trial designed to evaluate the effects of intravenous NAC on patients with acute coronary syndromes (ACS)undergoing coronary angiography and/or percutaneous coronary intervention (PCI). The medication Acetadote is provided by Cumberland Pharmaceuticals Inc (www.cumberlandpharma.com).

Patients will be excluded if they have end-stage renal disease requiring dialysis,known hypersensitivity to NAC or a history of life-threatening contrast reaction. Primary end-point is incidence of CIN. Secondary end-points are in-hospital mortality,30-day mortality,duration of hospitalization and change in serum cystatin C level.

Inclusion Criteria:

1. 18 years of age or older.
2. Hospitalized with a primary diagnosis of acute coronary syndrome.
3. Scheduled for coronary angiography or intervention during the current hospitalization.

Exclusion Criteria:

1. Have end-stage renal disease (ESRD) requiring dialysis.
2. Have a known hypersensitivity to NAC.
3. Have a history of life-threatening contrast reaction. -