Treating diverticulitis with amoxicillin-clavulanate spares risks tied to fluoroquinolones

Outpatient diverticulitis treatment with amoxicillin-clavulanate was “just as effective” as treatment with a combination of metronidazole and a fluoroquinolone, a researcher told Healio Primary Care.

Data show that treatment with amoxicillin-clavulanate does not carry the same risks for adverse events associated with fluoroquinolones.

According to researchers, acute diverticulitis is responsible for $5.5 billion in health care expenditures each year. The condition is common — 209 cases per 100,000 person-years in the United States.

“The two most commonly prescribed antibiotic regimens for outpatient diverticulitis are a combination of metronidazole and a fluoroquinolone or amoxicillin-clavulanate only,” said Anne Peery, MD, MSCR, assistant professor of medicine in the division of gastroenterology and hepatology at the University of North Carolina School of Medicine.

“While both regimens are considered first‐line therapy, they differ significantly in mechanisms of action and side effects,” she said. “This is the ideal comparative effectiveness study, particularly given the growing list of harms associated with fluoroquinolone use.”

Peery and colleagues compared the effectiveness and harms of the treatments in two cohorts of patients with acute diverticulitis. The first included U.S. residents aged 18 to 64 years in the IBM MarketScan Commercial Claims and Encounters Database (n = 119,521), and the second included Medicare patients aged 65 years or older between 2006 and 2015 (n = 20,348).

The researchers found that in the MarketScan cohort, there were no differences between treatment groups in the 1-year risk for hospital admission (risk difference [RD] = 0.1 percentage points; 95% CI, –0.3 to 0.6), 1-year risk for urgent surgery (RD = 0 percentage points; 95% CI, –0.1 to 0.1), 3-year risk for elective surgery (RD = 0.2 percentage points; 95% CI, –0.3 to 0.7) or 1-year risk for Clostridioides difficile (RD = 0 percentage points; 95% CI, –0.1 to 0.1).

In the Medicare cohort, there were no differences between the two treatment groups in the 1-year risk for hospital admission (RD = 0.1 percentage points; 95% CI, –0.7 to 0.9), 1-year risk for urgent surgery (RD = –0.2 percentage points; 95% CI, –0.6 to 0.1) or 3-year risk for elective surgery (RD = –0.3 percentage points; 95% CI, –1.1 to 0.4). The 1-year risk for C. difficile was higher for patients who received metronidazole plus a fluoroquinolone than those who received amoxicillin-clavulanate (RD = 0.6 percentage points; 95% CI, 0.2-1), according to the researchers.

“This is the first study to suggest that outpatient diverticulitis treatment with amoxicillin-clavulanate is just as effective as treatment with metronidazole with a fluoroquinolone,” Peery said. “Physicians should consider treating outpatient diverticulitis with amoxicillin-clavulanate instead of metronidazole with a fluoroquinolone. This approach has the potential to reduce the risk for numerous fluoroquinolone‐related harms, including Clostridioides difficile infection, without adversely affecting diverticulitis outcomes.”