What is the antibiotic treatment for diverticulitis?

From the Guidelines

Antibiotic treatment is only advised in patients with uncomplicated diverticulitis who have comorbidities, are frail, present with refractory symptoms or vomiting, or have a CRP >140 mg/L or baseline white blood cell count > 15 × 10^9 cells per liter, as well as in patients with complicated diverticulitis or uncomplicated diverticulitis with a fluid collection or longer segment of inflammation on CT scan. When antibiotic treatment is necessary, the regimen usually includes broad spectrum agents with gram-negative and anaerobic coverage, such as a combination of an oral fluoroquinolone and metronidazole or monotherapy with oral amoxicillin-clavulanate 1. The duration of treatment is usually 4–7 days but can be longer, depending on general health status, immune status, severity of presentation, CT findings, and patient expectations 1. Key factors that increase the risk of progression to complicated diverticulitis and thus warrant antibiotic treatment include baseline ASA score III or IV, duration of symptoms longer than 5 days prior to presentation, presence of vomiting, CRP >140 mg/L, and baseline white blood cell count > 15 × 10^9 cells per liter 1. Some important considerations for antibiotic selection include:

• Oral antibiotics for mild cases, such as amoxicillin-clavulanate or the combination of metronidazole plus a fluoroquinolone 1
• Intravenous antibiotics for more severe cases, with options including ceftriaxone plus metronidazole, piperacillin-tazobactam, or ertapenem 1
• Treatment duration tailored to the individual patient's response and risk factors 1.

From the Research

Antibiotic Treatment for Diverticulitis

• The use of antibiotics in the treatment of diverticulitis has been a topic of debate, with some studies suggesting that they may not be necessary for uncomplicated cases 2, 3.
• A study published in 2004 found that antibiotics such as ampicillin, gentamicin, metronidazole, piperacillin, and tazobactam were successfully used in clinical practice for severe and complicated diverticulitis, while ciprofloxacin, metronidazole, and rifaximin were used for uncomplicated diverticular disease 4.
• Another study published in 2024 found that several quality studies showed similar outcomes in cases of acute uncomplicated diverticulitis treated with or without antibiotics, leading to societal guidelines recommending against the routine use of antibiotics in acute uncomplicated diverticulitis 2.
• A 2010 study found that outpatient treatment with oral antibiotics was safe and effective for patients with uncomplicated acute diverticulitis, with only 3% of patients requiring admission due to persisting abdominal pain or vomiting 5.
• A survey conducted in 1999 found that the majority of colon and rectal surgeons chose an abdominal computed tomographic scan as the initial diagnostic test, and used a single intravenous antibiotic or oral antibiotics such as ciprofloxacin, amoxicillin/clavulanate, or metronidazole 6.
• A systematic review published in 2022 found that the evidence on antibiotic treatment for uncomplicated acute diverticulitis suggests that the effect of antibiotics is uncertain for complications, emergency surgery, recurrence, elective colonic resections, and long-term complications, with low-quality evidence and a need for more trials to obtain more precise effect estimates 3.

Types of Antibiotics Used

• The antibiotics used to treat diverticulitis include:
  • Ampicillin
  • Gentamicin
  • Metronidazole
  • Piperacillin
  • Tazobactam
  • Ciprofloxacin
  • Rifaximin
  • Amoxicillin/clavulanate
  • Doxycycline
  • Trimethoprim/sulfamethoxazole

Treatment Guidelines

• The American Society of Colon and Rectal Surgeons (ASCRS) and other societies recommend against the routine use of antibiotics in acute uncomplicated diverticulitis 2.
• Outpatient treatment with oral antibiotics may be safe and effective for patients with uncomplicated acute diverticulitis, but more studies are needed to confirm this 5.
• The choice of antibiotic and treatment duration may vary depending on the individual patient and the severity of the disease 4, 6.