N-acetylcysteine versus N-acetylcysteine + theophylline for the prevention of contrast nephropathy

Background The use of N‐acetylcysteine or theophylline in specific subgroups of patients has been suggested to reduce the incidence of contrast‐induced nephropathy (CIN) in patients undergoing angiographic procedures. Our purpose was to compare the use of N‐acetylcysteine versus N‐acetylcysteine + theophylline for the prevention of CIN. Materials and methods We randomized 217 patients with estimated glomerular filtration rate (eGFR) (calculated by Modification of Diet in Renal Disease formula) between 30 and 60 mL min^?1 1·73 m^?2 who were undergoing coronary angiography to three prophylactic treatment groups: Group 1: Intravenous hydration with isotonic saline (1 mL kg^?1 h^?1 for 12 h before and after contrast, n = 72). Group 2: Intravenous hydration with isotonic saline (1 mL kg^?1 h^?1 for 12 h before and after contrast)+ N‐acetylcysteine (600 mg p.o. twice daily the preceding day and the day of angiography, n = 73). Group 3: Intravenous hydration with isotonic saline (1 mL kg^?1 h^?1 for 12 h before and after contrast)+ N‐acetylcysteine + theophylline (600 mg N‐acetylcysteine p.o. and 200 mg theophylline p.o. twice daily for the preceding day and the day of angiography, n = 72). The incidence of CIN (0·5 mg dL^?1 increase in serum creatinine from the baseline value 48 h after intravascular injection of contrast) was compared in three groups. Results Of the 217 patients, 12 patients (5·5%) experienced CIN. Five patients (6·9%) in group 1, seven patients (9·6%) in group 2 and zero (0%) patients in group 3 experienced CIN (P < 0·033). Conclusion Among patients with eGFR between 30 and 60 mL min^?1 1·73 m^?2 undergoing coronary angiography, oral administration of N‐acetylcysteine + theophylline in addition to saline hydration has a beneficial effect in the prevention of CIN.