• Posted April 21, 2026

Powerful Antibiotic Combo Not Necessary For Simple Sinus Infections, Study Shows

People with sinus infections are often prescribed antibiotics that are more powerful than necessary, a new study has found.

Standard amoxicillin works just as well as the more potent combo of amoxicillin and clavulanate in treating sinus infections, researchers reported April 18 in the Journal of the American Medical Association.

Sinus infections cause more prescriptions for antibiotics than any other condition, but there’s no consensus which antibiotic is best for simple cases, researchers said.

“With nearly 5 million antibiotic prescriptions to adults with acute sinusitis in the U.S. each year, these findings have the potential to make a substantial impact on current treatment practices,” said lead researcher Dr. Timothy Savage, an associate epidemiologist at Mass General Brigham in Boston.

“We found no observed benefit to using amoxicillin-clavulanate, which supports standard‑dose amoxicillin as the preferred choice for adults with uncomplicated acute sinusitis,” Savage said in a news release.

Amoxicillin is a type of penicillin used to treat a wide variety of bacterial infections, according to Drugs.com.

Clavulanate inhibits an enzyme that makes bacteria resistant to amoxicillin, researchers said. However, not all bacteria that cause sinus infections make this enzyme, calling into question whether the amoxicillin-clavulanate combo is really necessary.

“Amoxicillin and amoxicillin‑clavulanate account for roughly 45% of antibiotic prescriptions for acute sinusitis, so it is essential that we identify the optimal option for patients,” Savage said.

For the new study, researchers analyzed insurance claims data for more than 521,000 adults diagnosed with acute sinusitis between 2018 and 2023. All patients had been prescribed a daily dose of either amoxicillin or amoxicillin-clavulanate.

Results showed there was no difference in treatment failure between amoxicillin (3.1%) and amoxicillin-clavulanate (3%).

Guidelines suggest the combo might benefit patients who are immunocompromised, but researchers found no difference in these patients either.

Further, there was a higher risk of secondary infections with the amoxicillin-clavulanate combo than with the straight antibiotic, researchers noted.

This included a 40% higher risk for subsequent yeast infections and a more than doubled risk for C. diff infections, the study said.

Using standard amoxicillin might also help health care professionals stem the rise of antibiotic-resistant bugs, Savage added.

“Preventing unnecessary exposure to a broader‑spectrum antibiotic can help reduce the potential risk of spreading antibiotic resistance,” Savage said.

It’s likely that many patients with inflamed sinuses don’t even need simple amoxicillin, and could get by without it, he said.

“Future research is needed to refine which patients will benefit from an antibiotic, and who are more likely to have viral infections and can be observed with supportive care,” Savage said.

More information

The Cleveland Clinic has more on acute sinusitis.

SOURCES: Mass General Brigham, news release, April 18, 2026; Journal of the American Medical Association, April 18, 2026