Theophylline, N-acetylcysteine, and Theophylline Plus N-acetylcysteine in Preventing Contrast-induced Nephropathy

The aim of this study is to determine the efficacy of Theophylline, N-Acetylcysteine and, and Theophylline plus N-acetylcysteine in the prevention of contrast-induced nephropathy. Investigators assume that Theophylline plus N-acetylcysteine is more effective than Theophylline alone and N-acetylcysteine alone. Investigators include patients referring for elective coronary angiography or angioplasty and allocate them to each of the mentioned treatments from 24 hours before to 48 hours after administration of contrast material. Investigators then measure serum creatinine and see if it is raised by ≥ 0.5 mg/dL or ≥ 25% of the baseline value.