SBP Prophylaxis in Cirrhotic Patients with Ascites
Patients who have recovered from one episode of SBP should receive continuous oral norfloxacin 400 mg once daily (or ciprofloxacin 500 mg once daily as an alternative) indefinitely until liver transplantation or resolution of ascites. 1
Secondary Prophylaxis (After Prior SBP Episode)
This is the most critical indication for prophylaxis, as the recurrence rate without treatment is approximately 70% at one year. 1
Norfloxacin 400 mg daily reduces SBP recurrence from 68% to 20% and reduces gram-negative bacterial SBP from 60% to 3%. 1
This prophylaxis improves 3-month survival from 62% to 94% and significantly impacts 1-year survival (60% vs 48%). 2
Ciprofloxacin 500 mg once daily is an acceptable alternative, commonly used in the UK. 1, 3
All patients with a history of SBP should be evaluated for liver transplantation, as 1-year survival is only 30-50% and falls to 25-30% at 2 years. 1, 3
Primary Prophylaxis (No Prior SBP)
Primary prophylaxis should be given to high-risk patients with low ascitic fluid protein (<15 g/L) AND one of the following: 3, 2
- Advanced liver failure (Child-Pugh score ≥9 points with serum bilirubin ≥3 mg/dL) 3, 2
- Impaired renal function (serum creatinine ≥1.2 mg/dL, BUN ≥25 mg/dL, or serum sodium ≤130 mEq/L) 2
For patients with ascitic fluid protein <10 g/L without these additional risk factors, there is no consensus among experts regarding primary prophylaxis. 1
- When indicated, norfloxacin 400 mg daily reduces 1-year probability of developing SBP from 61% to 7% and reduces hepatorenal syndrome from 41% to 28%. 2
Prophylaxis During Acute GI Bleeding
All cirrhotic patients with acute gastrointestinal bleeding require antibiotic prophylaxis, as bacterial infections occur in 25-65% of these patients. 4, 5
- For advanced liver disease: IV ceftriaxone 1g daily for 7 days 5
- For less severe disease: Norfloxacin 400 mg orally twice daily for 7 days 4, 5
Alternative Antibiotic Regimens
When norfloxacin is not available or tolerated:
- Ciprofloxacin 500 mg once daily is equally effective and well-tolerated. 3, 6
- Trimethoprim-sulfamethoxazole (800/160 mg) once daily has similar efficacy but higher risk of adverse events. 3, 7
- Rifaximin may be more effective than norfloxacin for secondary prophylaxis with fewer adverse events, though less extensively studied. 8
Critical Pitfalls and Monitoring
Long-term quinolone prophylaxis increases the risk of gram-positive bacterial infections (79% vs 33%), including MRSA. 1, 4
Monitor for signs of bacterial resistance and consider local resistance patterns when selecting antibiotics. 3, 4
Avoid weekly ciprofloxacin regimens despite one study showing non-inferiority, as this may promote quinolone-resistant organisms. 3, 6
Monitor for fluoroquinolone-associated tendon complications, particularly in patients with renal impairment. 3, 5
Restrict proton pump inhibitor use in cirrhotic patients, as PPIs may increase SBP risk. 3, 4
Perform diagnostic paracentesis immediately if clinical deterioration occurs despite prophylaxis. 5
Regular monitoring of renal function is essential in patients on prophylactic antibiotics. 3, 5