For Outpatient Diverticulitis, Amoxicillin–Clavulanate Preferable to Metronidazole Plus Fluoroquinolone?

By Amy Orciari Herman

Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

For patients receiving antibiotics for outpatient diverticulitis, amoxicillin–clavulanate seems preferable to metronidazole plus a fluoroquinolone, according to an observational study in the Annals of Internal Medicine.

Using medical claims data from 2000 to 2018, researchers identified nearly 120,000 adults aged 18 to 64 who received either metronidazole plus a fluoroquinolone (ciprofloxacin or levofloxacin) or amoxicillin–clavulanate alone for their first episode of outpatient diverticulitis. They also identified roughly 20,000 Medicare beneficiaries who received either regimen. Patients who were immunocompromised were excluded.

Nearly 90% of patients studied received metronidazole plus a fluoroquinolone, while the rest received amoxicillin–clavulanate. There were no significant differences between the treatments in risks for hospitalization for diverticulitis within 1 year, urgent surgery within 1 year, or elective surgery within 3 years.

Among Medicare beneficiaries, metronidazole-fluoroquinolone was associated with increased risk for Clostridioides difficile infection (CDI) within 1 year (1.2% vs. 0.6% with amoxicillin–clavulanate).

The researchers conclude that for outpatient diverticulitis, "physicians may consider treatment with amoxicillin–clavulanate over metronidazole-with-fluoroquinolone to reduce the risk for serious harms associated with fluoroquinolone use, including CDI."