Norfloxacin Dosage for SBP Prophylaxis in Cirrhotic Patients
The recommended dose of norfloxacin for spontaneous bacterial peritonitis (SBP) prophylaxis in cirrhotic patients is 400 mg once daily, taken orally. 1
Indications for SBP Prophylaxis
Secondary Prophylaxis
- Patients who have recovered from a previous episode of SBP should receive continuous prophylaxis with norfloxacin 400 mg once daily 1
- Secondary prophylaxis with norfloxacin reduces the probability of SBP recurrence from approximately 70% to 20% 1
- Without prophylaxis, the 1-year mortality after an episode of SBP is 50-70%, making prevention crucial 1
Primary Prophylaxis
- Consider primary prophylaxis in high-risk patients with ascitic fluid protein <1.5 g/dL 1
- Primary prophylaxis should be offered after careful consideration of risks and benefits, with patient communication about potential side effects 1
Alternative Regimens
If norfloxacin is unavailable (as is often the case in the UK), alternative options include:
- Ciprofloxacin 500 mg once daily orally 1
- Co-trimoxazole (800 mg sulfamethoxazole and 160 mg trimethoprim) once daily orally 1
Efficacy and Considerations
- Norfloxacin prophylaxis significantly reduces mortality in the first three months (94% vs 62% survival) 1
- The most recent evidence suggests rifaximin (550 mg twice daily) may be more effective than norfloxacin for secondary prophylaxis, with significantly lower SBP recurrence rates (7% vs 39%) 2
- Fluoroquinolones carry risks of side effects including tendon inflammation and damage, particularly in patients with renal impairment 1
- Long-term quinolone prophylaxis may increase the risk of gram-positive bacterial infections, including methicillin-resistant Staphylococcus aureus 1
Monitoring and Follow-up
- All patients with a history of SBP should be considered for liver transplantation evaluation, as they have poor long-term survival 1
- Regular monitoring of renal function is recommended in patients on prophylactic antibiotics 1
- Consider restricting proton pump inhibitor use in patients on SBP prophylaxis, as PPIs may increase SBP risk 1
Clinical Pitfalls
- Bacterial resistance is an increasing concern with long-term fluoroquinolone use 1, 3
- Weekly ciprofloxacin regimens have been studied but may lead to higher rates of quinolone-resistant organisms and should be avoided 1, 4
- Adding probiotics to norfloxacin does not improve efficacy in preventing SBP 5
- Always consider local bacterial resistance patterns when selecting prophylactic antibiotics 1, 3