We excluded patients with a (i) CK > 5,000 or the presence of myoglobinuria, (ii) a known allergy or hypersensitivity reaction to radiographic contrast dye or NAC, (iii) serious illness with imminent threat of dying (low likelihood of survival within 48-hours) or poor prognosis, (iv) pregnancy, (v) patients with cardiogenic shock (NYHA class 3 or 4 symptoms), (vi) known or suspected nephritic, nephrotic or pulmonary-renal syndromes, (vii) a post renal etiology of renal impairment, (viii) previous renal transplant, (ix) known solitary kidney, (x) serum creatinine > 200 µmol/L or (xi) recent exposure to radiographic contrast within 14 days of randomization.