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 ۹۶ 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 (۲۰۰ mg), N-acetylcysteine (۶۰۰ mg), or theophylline + N-acetylcysteine, twice a day, from ۲۴ h before to ۴۸ h after administration of the contrast material. A non-ionic, low-osmolar contrast material was used. Serum creatinine was measured before and ۴۸ h after contrast material injection. RESULTS: Serum creatinine was increased by ۶.۸۳ ± ۱۵.۳۲% with theophylline, ۱۳.۰۹ ± ۱۴.۶۳% with N-acetylcysteine, and ۵.۴۵ ±۱ ۳.۹۶% with theophylline + N-acetylcysteine after contrast material injection (between group P = ۰.۰۷۲). 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 = ۴.۷۹, P = ۰.۰۳۳), and with theophylline + N-acetylcysteine compared with N-acetylcysteine (F = ۵.۷۸, P = ۰.۰۲۰). CIN (increase in creatinine of ≥ ۰.۵ mg/dl or ≥ ۲۵% from the baseline) was occurred in ۲۰%, ۲۱.۹%, and ۷.۱% of patients in the theophylline, N-acetylcysteine, and theophylline + N-acetylcysteine groups, respectively (P = ۰.۲۶۰). 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.