Spontaneous Bacterial Peritonitis (SBP) Prophylaxis in Cirrhosis
Patients who have recovered from an episode of SBP must receive continuous prophylaxis with norfloxacin 400 mg once daily (or ciprofloxacin 500 mg once daily) indefinitely until liver transplantation or resolution of ascites. 1
Secondary Prophylaxis (After Prior SBP Episode)
All patients with a history of SBP require lifelong prophylaxis because the recurrence rate without prophylaxis reaches approximately 70% at one year, with dismal survival rates of only 30-50% at one year. 1
Antibiotic Options for Secondary Prophylaxis:
First-line: Norfloxacin 400 mg once daily - reduces SBP recurrence from 68% to 20% and improves 3-month survival from 62% to 94%. 1, 2, 3
Alternative: Ciprofloxacin 500 mg once daily - commonly used in the UK and equally effective. 1, 2
Alternative: Trimethoprim-sulfamethoxazole (800/160 mg) once daily - similar efficacy but may have increased adverse events. 2, 3
Emerging option: Rifaximin 550 mg twice daily - a 2022 randomized trial showed superior efficacy compared to norfloxacin for secondary prophylaxis (7% vs 39% recurrence, P=0.004), with fewer hepatic encephalopathy episodes and no resistance concerns. 4
Critical point: All patients with prior SBP should be immediately referred for liver transplantation evaluation due to poor long-term prognosis. 1, 3
Primary Prophylaxis (No Prior SBP)
Primary prophylaxis is indicated for high-risk patients with ascitic fluid protein <15 g/L (or <1.5 g/dL) PLUS any of the following:
- Child-Pugh score ≥9 points 2, 3
- Serum bilirubin ≥3 mg/dL 3
- Impaired renal function (creatinine >1.2 mg/dL or serum sodium <130 mEq/L) 2
Efficacy of Primary Prophylaxis:
Norfloxacin 400 mg daily reduces the 1-year probability of developing SBP from 61% to 7% in high-risk patients. 2, 5 A 1998 double-blind randomized trial showed severe infections developed in 17% of placebo patients versus only 2% in the norfloxacin group (P<0.03). 5
Important caveat: For patients with ascitic fluid protein <10 g/L without other high-risk features, there is no consensus among experts regarding primary prophylaxis, though the evidence leans toward benefit. 1
Prophylaxis During Acute Gastrointestinal Bleeding
Every cirrhotic patient with acute GI bleeding requires antibiotic prophylaxis because bacterial infections occur in 25-65% of these patients and significantly increase mortality. 2, 6
Regimen Selection Based on Disease Severity:
Advanced liver disease (Child-Pugh B/C): IV ceftriaxone 1g daily for 7 days 2, 6
Less severe disease (Child-Pugh A): Norfloxacin 400 mg orally twice daily for 7 days 2, 6
Critical Monitoring and Pitfalls
Resistance Concerns:
Long-term quinolone prophylaxis shifts the bacterial spectrum toward gram-positive infections (79% vs 33%), including methicillin-resistant Staphylococcus aureus. 1, 2 Consider local resistance patterns when selecting antibiotics. 3, 6
Weekly Ciprofloxacin - A Reasonable Alternative:
A 2018 randomized controlled trial demonstrated that ciprofloxacin 500 mg once weekly was non-inferior to daily norfloxacin (5.3% vs 7.3% SBP development, P=0.712) with comparable survival rates. 7 However, guidelines still recommend daily dosing as the standard approach. 2, 3
Monitoring Requirements:
Regular renal function monitoring is essential in all patients on prophylactic antibiotics. 2, 3
Monitor for tendon pain or inflammation (fluoroquinolone side effect) and discontinue immediately if it occurs. 2, 3
Perform diagnostic paracentesis if any clinical deterioration, encephalopathy, renal impairment, or peripheral leukocytosis develops. 1, 3
Proton Pump Inhibitor Caution:
Restrict PPI use in cirrhotic patients as PPIs may increase SBP risk through alterations in gut flora. 2, 3, 6
Adjunctive Therapy:
A 2005 randomized trial showed that adding cisapride 20 mg twice daily to norfloxacin reduced 12-month SBP incidence from 56.8% to 21.7% (P=0.026), though cisapride availability is limited due to cardiac side effects. 8