From the Guidelines
Intravenous antibiotics are recommended for moderate to severe diverticulitis requiring hospitalization, with a suggested regimen of metronidazole 500mg every 8 hours plus either ceftriaxone 1-2g daily or ciprofloxacin 400mg every 12 hours, as supported by the most recent guidelines 1.
Key Considerations
- The choice of antibiotic regimen should be based on the severity of infection, the pathogens presumed to be involved, and the risk factors for major antimicrobial resistance patterns 1.
- Patients with penicillin allergies can be treated with alternatives such as aztreonam 1-2g every 8 hours with metronidazole.
- In more severe cases or with complications like perforation or abscess, broader coverage with piperacillin-tazobactam 3.375g every 6 hours or meropenem 1g every 8 hours may be used.
- The duration of antibiotic therapy is typically 7-10 days, with transition to oral antibiotics once clinical improvement occurs (usually after 2-4 days) 1.
Oral Antibiotic Options
- Amoxicillin-clavulanate 875/125mg twice daily or ciprofloxacin 500mg twice daily plus metronidazole 500mg three times daily can be used for transition to oral antibiotics.
Rationale
- IV antibiotics are necessary to achieve rapid therapeutic blood levels to combat the polymicrobial infection involving both aerobic and anaerobic gut bacteria that have translocated through the inflamed diverticular wall, causing localized or systemic infection.
- The most recent guidelines suggest that antibiotic treatment should be advised in patients with uncomplicated diverticulitis who have comorbidities or are frail, who present with refractory symptoms or vomiting, or who have a CRP >140 mg/L or baseline white blood cell count > 15 × 109 cells per liter 1.
From the FDA Drug Label
Ciprofloxacin Injection, USP is indicated for the treatment of infections caused by susceptible strains of the designated microorganisms in the conditions and patient populations listed below when the intravenous administration offers a route of administration advantageous to the patient. Complicated Intra-Abdominal Infections (used in conjunction with metronidazole) caused by Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, or Bacteroides fragilis
The ciprofloxacin (IV) can be used for the treatment of complicated intra-abdominal infections, which may include diverticulitis, in combination with metronidazole 2.
From the Research
IV Antibiotics for Diverticulitis
- The use of IV antibiotics for diverticulitis is a topic of ongoing debate, with some studies suggesting that antibiotics may not be necessary for uncomplicated cases 3.
- A study published in the Journal of Clinical Gastroenterology found that antibiotics play a key role in the management of both uncomplicated and complicated diverticular disease, and that rifaximin has demonstrated effectiveness in obtaining symptom relief and improving symptoms in patients with uncomplicated diverticulitis 4.
- However, a systematic review published in The Cochrane Database of Systematic Reviews found that the evidence on antibiotic treatment for uncomplicated acute diverticulitis is limited and of low quality, and that the effect of antibiotics on complications, emergency surgery, recurrence, and long-term complications is uncertain 3.
- Another study published in Colorectal Disease found that outpatient treatment with oral antibiotics is safe and effective for patients with uncomplicated acute diverticulitis, and that only a small percentage of patients require admission to hospital 5.
- A comparative effectiveness study published in Annals of Internal Medicine found that treating diverticulitis in the outpatient setting with amoxicillin-clavulanate may reduce the risk of fluoroquinolone-related harms without adversely affecting diverticulitis-specific outcomes 6.
Complicated Diverticulitis
- For patients with complicated diverticulitis, IV antibiotics are often necessary, and the choice of antibiotic regimen should be based on the severity of the disease and the presence of any underlying comorbidities 4.
- A study published in the Journal of Clinical Gastroenterology found that in patients with acute diverticulitis who develop an abscess, conservative treatment with broad-spectrum antibiotics is successful in up to 70% of cases 4.
Outpatient Treatment
- Outpatient treatment with oral antibiotics is a viable option for patients with uncomplicated diverticulitis, and can reduce the need for hospital admission and IV antibiotics 5, 6.
- A study published in Annals of Internal Medicine found that treating diverticulitis in the outpatient setting with amoxicillin-clavulanate may reduce the risk of fluoroquinolone-related harms without adversely affecting diverticulitis-specific outcomes 6.