Following a first episode of spontaneous bacterial peritonitis, the recurrence rate at one year is ~70%, with a 1-year overall survival rate of 30-50% in patients who do not receive antibiotic prophylaxis. Cirrhotic patients with ascites and a prior history of SBP, receiving antibiotic prophylaxis there is a reduction in the risk of recurrence from 68% to 20%. Accordingly, daily long-term antimicrobial prophylaxis are recommended for patients with a history of one or more episodes of SBP.^[1]

Several studies have shown that oral norfloxacin 400 mg daily prevents spontaneous bacterial peritonitis in patients with low-protein ascites and those with previous history of spontaneous bacterial peritonitis (SBP). Norfloxacin reduced SBP recurrence rates from 68% to 20%.

• Alternative regimens that have been studied include oral double-strength trimethoprim-sulfamethoxazole 5 doses per week or oral ciprofloxacin 750 mg once a week, but intermittent dosing may lead to resistance.
• In addition, prolonged use of antibiotic prophylaxis has led to the development of gram-negative bacterial resistance (to fluoroquinolones and trimethoprim-sulfamethoxazole), as well as an increased likelihood of developing gram-positive infections.
• Daily long-term dosing with norfloxacin has been proved to be superior to in-hospital administration of norfloxacin.^[2]
• All patients who have survived an episode of SBP should receive long-term prophylaxis with daily norfloxacin (or trimethoprim/sulfamethoxazole) because this is the most data-supported indication for long-term outpatient prophylaxis to prevent future episodes ( 40-70% risk of recurrence in 1 year ). ^[3][4][5][6]
• Rifaximin was more effective than norfloxacin in the secondary prevention of SBP as encephalopathy-related mortality and side effects were fewer with rifaximin than norfloxacin.^[7][8]