Indications for Spontaneous Bacterial Peritonitis (SBP) Prophylaxis
All patients with cirrhosis and ascites who have recovered from one episode of SBP should receive continuous antibiotic prophylaxis with norfloxacin 400 mg daily (or ciprofloxacin 500 mg once daily), as this reduces recurrence from 68% to 20% and improves survival. 1, 2
Secondary Prophylaxis (Highest Priority)
Patients with prior SBP require lifelong prophylaxis unless they undergo liver transplantation, as the one-year recurrence rate without prophylaxis approaches 70% and one-year mortality is 50-70%. 2, 3
- Norfloxacin 400 mg once daily is the first-line agent, reducing SBP recurrence from 68% to 20% and improving three-month survival from 62% to 94%. 1, 2
- Ciprofloxacin 500 mg once daily is an acceptable alternative, commonly used in the UK. 1, 3
- All patients with prior SBP should be evaluated for liver transplantation due to poor long-term prognosis. 1, 3
Primary Prophylaxis
Patients with low ascitic fluid protein (<15 g/L) combined with advanced liver disease should receive prophylaxis, as this population has high risk for first SBP episode. 2, 3
Specific high-risk criteria warranting primary prophylaxis include:
Ascitic fluid protein <15 g/L (some guidelines use <10 g/L cutoff) with any of the following: 2, 3
Norfloxacin 400 mg daily reduces one-year probability of developing SBP from 61% to 7% in this population. 2
Gastrointestinal Bleeding
All cirrhotic patients with gastrointestinal bleeding require antibiotic prophylaxis regardless of ascites status, as this is the most frequently overlooked indication in clinical practice. 3, 4
- For severe liver disease, IV ceftriaxone 1g daily for 7 days is recommended. 3
- GI hemorrhage accounted for 44% of preventable SBP cases in one analysis. 4
Antibiotic Selection and Alternatives
- Norfloxacin 400 mg daily remains the most extensively studied and recommended first-line agent. 1, 3
- Ciprofloxacin 500 mg once daily is an acceptable alternative with similar efficacy. 1, 2
- Trimethoprim-sulfamethoxazole (800/160 mg once daily) can be used but has higher adverse event rates than norfloxacin. 2, 5
- Rifaximin may be more effective than norfloxacin for secondary prophylaxis with fewer adverse events, though less extensively studied. 5
Critical Pitfalls and Considerations
Long-term quinolone prophylaxis increases risk of gram-positive infections (79% vs 67%), including MRSA, which should prompt consideration of alternative antibiotics in patients with breakthrough infections. 1, 3
- Monitor for quinolone side effects including tendon inflammation, particularly in patients with renal impairment. 2, 3
- Consider local bacterial resistance patterns when selecting prophylactic antibiotics. 2, 3
- Avoid weekly ciprofloxacin regimens as they may promote quinolone-resistant organisms. 2
- Restrict proton pump inhibitor use in cirrhotic patients, as PPIs increase SBP risk. 2, 3
- Perform diagnostic paracentesis if clinical deterioration occurs despite prophylaxis. 2
Adherence Gap
62% of SBP cases in one study were potentially preventable through proper adherence to prophylaxis guidelines, with GI hemorrhage being the most commonly missed indication. 4 Only one-third of patients who survived SBP received appropriate long-term outpatient prophylaxis after discharge. 4