Efficacy of N-Acetylcysteine in Prevention of Post-Catheterization Contrast-Induced Nephropathy in Diabetic Patients With Chronic Kidney Disease

* 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.