What are the oral antibiotics for Spontaneous Bacterial Peritonitis (SBP)?

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From the Guidelines

Oral antibiotics can be used to treat spontaneous bacterial peritonitis (SBP) in select patients with cirrhosis who are clinically stable, with the preferred oral regimen being ofloxacin 400 mg twice daily for 7 days, as shown in a study by Navasa et al. 1.

Key Considerations

  • The use of oral antibiotics should be limited to patients without sepsis, shock, ileus, gastrointestinal bleeding, renal dysfunction, or hepatic encephalopathy.
  • Patients must be able to tolerate oral medications and should show clinical improvement within 48 hours.
  • If improvement is not observed, the patient should be switched to intravenous antibiotics and reassessed.

Rationale

  • The rationale for using oral ofloxacin is its gram-negative coverage, particularly against Escherichia coli and Klebsiella species, which are common causative organisms in SBP, and its good penetration into ascitic fluid.
  • A study by Navasa et al. 1 showed that ofloxacin has similar therapeutic efficacy to cefotaxime in patients without complications.

Alternative Options

  • Alternative oral regimens, such as amoxicillin/clavulanic acid, may also be considered, but their use should be guided by local resistance profiles and the severity of infection.
  • The use of quinolones, such as ciprofloxacin, should be cautious due to the increasing resistance rates, as reported in a study by Terg et al. 1.

Monitoring and Adjustment

  • Patients should be closely monitored for clinical improvement and potential side effects.
  • Antibiotic therapy should be adjusted based on culture results and susceptibility testing, as recommended by the American Association for the Study of Liver Diseases 1.

From the Research

Oral Antibiotics for Spontaneous Bacterial Peritonitis (SBP)

  • The use of oral antibiotics for SBP is supported by several studies, including 2, which suggests the use of norfloxacin 400 mg daily for primary prophylaxis in patients with low-protein ascites.
  • Another study 3 found that daily norfloxacin is effective as a prophylactic antibiotic for the prevention of SBP in patients with cirrhosis.
  • The study 3 also compared the efficacy of norfloxacin with other antibiotics, such as ciprofloxacin, trimethoprim-sulfamethoxazole, and rifaximin, and found that rifaximin was more effective than norfloxacin in secondary prophylaxis of SBP.
  • The use of oral antibiotics for SBP is also mentioned in 4, which suggests that levofloxacin is an acceptable alternative for patients not receiving long-term fluoroquinolone prophylaxis or for those with a penicillin allergy.
  • However, the study 5 notes that long-term quinolonic prophylaxis can cause the emergence of multidrug-resistant agents, which can complicate the treatment of SBP.

Specific Oral Antibiotics Used for SBP

  • Norfloxacin: 400 mg daily for primary prophylaxis in patients with low-protein ascites 2, and daily for prevention of SBP in patients with cirrhosis 3.
  • Ciprofloxacin: once weekly, not inferior to once daily norfloxacin, with good tolerance and no induced resistance 3.
  • Trimethoprim-sulfamethoxazole: similar efficacy to norfloxacin for primary and secondary prophylaxis of SBP, but associated with an increased risk of developing an adverse event 3.
  • Rifaximin: more effective than norfloxacin in secondary prophylaxis of SBP, with a significant decrease in adverse events and mortality rate 3.
  • Levofloxacin: an acceptable alternative for patients not receiving long-term fluoroquinolone prophylaxis or for those with a penicillin allergy 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Spontaneous Bacterial Peritonitis.

Current treatment options in gastroenterology, 2002

Research

Treatment of Spontaneous Bacterial Peritonitis.

Digestive diseases (Basel, Switzerland), 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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