What is the recommended prophylaxis regimen for Spontaneous Bacterial Peritonitis (SBP)?

Recommended Prophylaxis Regimen for Spontaneous Bacterial Peritonitis (SBP)

Norfloxacin 400 mg once daily is the first-choice prophylactic regimen for SBP prevention in high-risk patients with cirrhosis and ascites. 1

Indications for SBP Prophylaxis

SBP prophylaxis should be initiated in the following scenarios:

1. Secondary Prophylaxis:

   • All patients who have survived a previous episode of SBP should receive indefinite antibiotic prophylaxis until liver transplantation or resolution of ascites 1
   • Without prophylaxis, recurrence rates reach 70% at 1 year with only 30-50% survival at 1 year 1

2. Primary Prophylaxis:

   • Patients with low ascitic fluid protein (<1.5 g/dL) AND at least one of:
     • Child-Pugh score ≥9 with serum bilirubin >3 mg/dL
     • Impaired renal function
     • Serum sodium <130 mEq/L 1
   • High serum bilirubin (>3.2 mg/dL) and low platelet count (<98,000/mm³) are independent risk factors for developing first SBP episode 2

3. Gastrointestinal Bleeding:

   • All cirrhotic patients with ascites and acute GI hemorrhage should receive short-term prophylaxis for 7 days 1

Recommended Prophylactic Regimens

First-Line Options:

• Norfloxacin 400 mg once daily (first choice) 1
  • Reduces SBP recurrence from 68% to 20%
  • Particularly effective against gram-negative bacteria

Alternative Options:

• Ciprofloxacin 500 mg once daily (primary alternative) 1
  • Weekly ciprofloxacin 750 mg has also shown efficacy in reducing SBP incidence (3.6% vs 22% with placebo) 3
• Trimethoprim-sulfamethoxazole 800/160 mg daily (alternative option) 1
• Rifaximin (emerging evidence suggests possibly superior efficacy) 1

For Acute GI Bleeding:

• IV ceftriaxone for 7 days OR
• Norfloxacin 400 mg twice daily for 7 days 1

Monitoring During Prophylaxis

• Check renal function every 1-3 months 1
• Perform periodic cultures to detect resistant organisms 1
• Monitor for fluoroquinolone side effects:
  • Rare but serious musculoskeletal complications
  • Nervous system side effects 1
• Monitor for trimethoprim-sulfamethoxazole adverse events:
  • Rash
  • Hyperkalemia
  • Bone marrow suppression 1

Important Considerations and Pitfalls

• Underutilization: Despite clear guidelines, only one-third of patients who survive SBP receive appropriate long-term prophylaxis after discharge 1

• Antibiotic Resistance: Long-term prophylaxis has led to increasing gram-positive and multi-drug resistant organisms 1

  • Consider alternative antibiotics if infection develops with resistant bacteria
  • Quinolone prophylaxis is less effective in patients colonized with multi-drug resistant organisms

• Mortality Benefit: Meta-analyses demonstrate that fluoroquinolone prophylaxis reduces not only SBP incidence but also mortality in high-risk patients 4

• Albumin Consideration: For active SBP treatment (not prophylaxis), human albumin administration in addition to antibiotics decreases hepatorenal syndrome frequency and improves survival 1

The evidence strongly supports that the benefits of prophylaxis in appropriate candidates outweigh the risks of long-term antibiotic use, with significant reductions in infection rates and mortality 1, 4.