Augmentin causes an increase in C difficile and yeast infection

In a cohort of over 521,000 adults treated for acute sinusitis, amoxicillin and amoxicillin‑clavulanate showed no meaningful difference in treatment failure¹. Adverse events were uncommon overall, but amoxicillin‑clavulanate carried higher risks of secondary infections.

Patients receiving amoxicillin‑clavulanate had higher rates of yeast infections (1.1% vs 0.8%; RR 1.40) and a double rate of C difficile infection (0.04% vs 0.02%; RR 2.14), representing small absolute but clinically relevant differences (compared with pure amoxicillin). Clinicians need to specifically ask the lab for C diff toxin using a fresh loose stool. A regular stool culture does not get C diff.

In NZ, sinusitis, even when symptoms persist for more than 3 days with fever or 10 days without fever, should first be treated symptomatically with sinus rinses and decongestants^2.

Reference:

1. Amoxicillin-Clavulanate vs Amoxicillin for Acute Sinusitis in Adults JAMA (2026)

2. Aotearoa antibiotic prescribing guidelines

Click here to view more Gems

Goodfellow Gems are chosen by Goodfellow Director, Prof Bruce Arroll to be either practice changing or thought provoking. If this email was forwarded to you and you would like to automatically receive Goodfellow Gems Click here.