Comparison between theophylline, N-acetylcysteine, and theophylline plus N-acetylcysteine for the prevention of contrast-induced nephropathy

BACKGROUND: Few studies compared the efficacy of theophylline with N-acetylcysteine or evaluated the efficacy of combination therapy in the prevention of contrast-induced nephropathy (CIN). We compared the efficacy of theophylline, N-acetylcysteine, and the combination of these agents in the prevention of CIN. METHODS: This randomized controlled trial was conducted on 96 patients referring consecutively to the Shahid Chamran University Hospital in Isfahan, Iran, for elective coronary angiography (with our without angioplasty). Patients with at least moderate risk for CIN were included and were randomized to receive theophylline (200 mg), N-acetylcysteine (600 mg), or theophylline + N-acetylcysteine, twice a day, from 24 h before to 48 h after administration of the contrast material. A non-ionic, low-osmolar contrast material was used. Serum creatinine was measured before and 48 h after contrast material injection. RESULTS: Serum creatinine was increased by 6.83 ± 15.32% with theophylline, 13.09 ± 14.63% with N-acetylcysteine, and 5.45 ±1 3.96% with theophylline + N-acetylcysteine after contrast material injection (between group P = 0.072). Controlling for Mehran risk score, baseline serum creatinine, and contrast volume, the change in serum creatinine level was lower with theophylline compared with N-acetylcysteine (F = 4.79, P = 0.033), and with theophylline + N-acetylcysteine compared with N-acetylcysteine (F = 5.78, P = 0.020). CIN (increase in creatinine of ≥ 0.5 mg/dl or ≥ 25% from the baseline) was occurred in 20%, 21.9%, and 7.1% of patients in the theophylline, N-acetylcysteine, and theophylline + N-acetylcysteine groups, respectively (P = 0.260). CONCLUSION: Theophylline is superior to N-acetylcysteine in preventing contrast-induced renal dysfunction, but the combination with N-acetylcysteine is not superior to theophylline alone in this regard. Further trials with larger sample of patients are warranted.