Randomized-controlled trial of rifaximin versus norfloxacin for secondary prophylaxis of spontaneous bacterial peritonitis.

BACKGROUND AND AIMS: Spontaneous bacterial peritonitis (SBP) is a serious complication of liver cirrhosis with a high recurrence rate and a marked increase in mortality. Norfloxacin is used widely for the secondary prophylaxis of SBP; however, its extensive long-term use has led to an increase in the incidence of quinolone-resistant and Gram-positive SBP. Rifaximin is a nonabsorbable broad-spectrum antibiotic and does not appear to promote emergence of resistance. The aim of this study was to compare the safety and efficacy of rifaximin versus norfloxacin for the secondary prevention of SBP in patients with liver cirrhosis and ascites.

MATERIALS AND METHODS: Two hundred and sixty two cirrhotic patients with ascites and a previous episode of SBP were assigned randomly to receive either 1200 mg rifaximin or 400 mg of norfloxacin daily for 6 months. All patients were monitored clinically each month and with ascitic fluid examination at the end of 2 and 6 months if not clinically suspected of recurrence earlier.

RESULTS: Recurrence of SBP was significantly lower in the rifaximin group (3.88 vs. 14.13%) compared with the norfloxacin group (P=0.04). The mortality rate was significantly decreased in the rifaximin group (13.74 vs. 24.43%) compared with the norfloxacin group (P=0.044). The causes of death between the two groups did not show a significant difference (P=0.377), but encephalopathy-related deaths were three folds higher in the norfloxacin group. There was a significant decrease in the side effects in the rifaximin group versus the norfloxacin group (P=0.033).

CONCLUSION: Rifaximin was more effective than norfloxacin in the secondary prevention of SBP. Encephalopathy-related mortality and side effects were fewer in the rifaximin group.