• Contrast-induced nephropathy (CIN) is the third most common cause of hospital acquired acute kidney injury, accounting for 10% of all cases.

• The pathophysiology of CIN is unclear. Possible mechanisms involve

  1. Renal tubular injury by oxygen free radicals
  2. Reducing renal blood flow which leads to acute tubular necrosis. Since N-acetylcysteine is an antioxidant as well as a vasodilator, it may work in two distinct ways, by preventing reduction in renal blood flow or contrast-induced oxidative damage.

• The purpose of this study is to evaluate the efficacy of N-acetylcysteine compared to placebo for the contrast-induced nephropathy prevention.

• Contrast-induced nephropathy (CIN) is the third most common cause of hospital acquired acute kidney injury, accounting for 10% of all cases. Nevertheless, use of radiocontrast media has been associated with increased in-hospital morbidity, mortality, and costs of medical care, long admission, especially in patients needing dialysis. With the increasing use of contrast media in diagnostic and interventional procedures, it has become one of the major challenges encountered during routine cardiovascular practice.
• Patients at the greatest risk for CIN can be defined as those have preexisting impaired renal function and diabetes mellitus with incidence estimated to be as high as 50%. Preventive therapies primarily include limitation of contrast exposure, intravenous volume expansion with a saline solution, and use of a low- or iso-osmolality contrast media.
• However, since these measures provide incomplete protection for CIN, interest has emerged in a number of adjunction short-term pharmacotherapy methods. Among them, N-acetylcysteine (NAC) has been of considerable interest. Up to now, several clinical studies and meta-analysis have been performed to assess the efficacy of NAC in prevention of CIN.
• In spite of heterogeneity regarding efficacy of administration of NAC, several studies have advised the use of NAC, especially in high risk patients, with regard to its low cost, availability and few side effects. Since administration of NAC necessitates earlier and longer admission of patients, particularly in intravenous use, it can increase the health care costs. In addition, there are evidences that this intervention can even be harmful in patients with diabetes mellitus.
• So, it seems that we need more evidences about the efficacy and cost-effectiveness of NAC in patients at high risk for development of CIN to make rational clinical decisions for individual patients as well as policy decisions for the health of the general public.

Inclusion Criteria:

Patients who have all of the following criteria:

• Aged older than 18 years old
• A history of diabetes mellitus for at least one year
• chronic kidney disease, defined as serum creatinine concentration >=1.5mg/dL for men and >=1.4mg/dL for women.

Exclusion Criteria:

• Acute coronary syndrome requiring primary or rescue coronary intervention within less than 12h
• Cardiogenic shock
• Current peritoneal or hemo-dialysis
• A known allergy to NAC