Trimethoprim-sulfamethoxazole versus norfloxacin in the prophylaxis of spontaneous bacterial peritonitis in cirrhosis

BACKGROUND: The prognosis of patients with chronic liver disease and spontaneous bacterial peritonitis is poor, being of great importance its prevention. AIM: To compare the effectiveness of trimethoprim-sulfamethoxazole versus norfloxacin for prevention of spontaneous bacterial peritonitis in patients with cirrhosis and ascites. PATIENTS AND METHODS: Fifty seven patients with cirrhosis and ascites were evaluated between March 1999 and March 2001. All of them had a previous episode of spontaneous bacterial peritonitis or had ascitic fluid protein concentration < or = 1 g/dL and/or serum bilirubin > or = 2.5 mg/dL. The patients were randomly assigned to receive either 800/160 mg/day of trimethoprim-sulfamethoxazole 5 days a week or 400 mg of norfloxacin daily. The mean time of observation was 163 days for the norfloxacin group and 182 days for the trimethoprim-sulfamethoxazole group. In the statistical analysis, differences were considered significant at the level of 0.05. RESULTS: According to the inclusion criteria, 32 patients (56%) were treated with norfloxacin and 25 (44%) with trimethoprim-sulfamethoxazole. Spontaneous bacterial peritonitis occurred in three patients receiving norfloxacin (9.4%) and in four patients receiving trimethoprim-sulfamethoxazole (16.0%). Extraperitoneal infections occurred in 10 patients receiving norfloxacin (31.3%) and in 6 patients receiving trimethoprim-sulfamethoxazole (24.0%). Death occurred in seven patients (21.9%) who received norfloxacin and in five (20.0%) who received trimethoprim-sulfamethoxazole. Side effects occurred only in the trimethoprim-sulfamethoxazole group. CONCLUSION: In spite of the reduced number of patients and time of observation, trimethoprim-sulfamethoxazole and norfloxacin were equally effective in spontaneous bacterial peritonitis prophylaxis, suggesting that trimethoprim-sulfamethoxazole is a valid alternative to norfloxacin.