Effectiveness of amoxicillin and amoxicillin-clavulanate for the treatment of community-acquired pneumonia in adults and children: a systematic review and meta-analysis

Journal article

Objectives: The aim of this study is to evaluate existing evidence on the effectiveness of amoxicillin and amoxicillin-clavulanate for community-acquired pneumonia in children and adults. Design: Systematic review and meta-analysis. Data sources: PubMed, Cochrane Library, Web of Science and Ovid-MEDLINER were searched with no language restrictions through 16 July 2024. Eligibility criteria: We included studies comparing the effectiveness of amoxicillin or amoxicillin-clavulanate versus other antibiotics or placebo. Data extraction and synthesis: Only randomised controlled trials comparing amoxicillin or amoxicillin-clavulanate with another antibiotic or placebo with a primary outcome of clinical resolution or clinical failure were eligible for our review. We used random-effects and fixed-effects logistic regression models to estimate the pooled treatment effect size. Heterogeneity of the studies was evaluated using the τ statistic. We performed an unplanned frequentist random-effects network meta-analysis for the indirect comparison between amoxicillin and amoxicillin-clavulanate. The revised Cochrane risk of bias tool for randomised trials was used to assess and categorise studies into low risk of bias, some concerns or high risk of bias. Results: We extracted data from 44 studies including 45 400 patients. We found no evidence of a differential effect on clinical resolution when comparing amoxicillin with other antibiotics (n=15 trials; pooled OR 0.88; 95% CI 0.56 to 1.38, where >1 favours amoxicillin) or amoxicillin-clavulanate with other antibiotics (n=17; OR 0.89; 95% CI 0.76 to 1.04). Similarly, evidence of difference in clinical failure between amoxicillin and other antibiotics was unclear and unable to rule out clinically important benefits or harms (n=8; OR 0.76; 95% CI 0.55 to 1.06, where <1 favours amoxicillin). We found no evidence of a differential effect on clinical resolution between adults treated with amoxicillin and amoxicillin-clavulanate (n=28; OR 1.04; 95% CI 0.64 to 1.70, where >1 favours amoxicillin-clavulanate). Sixty-three per cent and 29% of amoxicillin and amoxicillin-clavulanate studies, respectively, had low risk of bias according to the Cochrane risk of bias tool for randomised trials. Conclusions: Current evidence is unclear as to whether amoxicillin or amoxicillin-clavulanate differs from other antibiotics, or from each other, in the treatment of community-acquired pneumonia, owing to the small number of trials and substantial heterogeneity in comparators used across study settings. PROSPERO registration number: CRD42024568554.

Authors: Potter-Schwartz, L; Swe, MM; Sharland, M; Bielicki, JA; Cooper, BS

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: BMJ Publishing Group
• Journal: BMJ Open
• Volume: 16
• Issue: 5
• Pages: e112219
• Article number: bmjopen-2025-112219
• Publication date: 2026-05-07
• Acceptance date: 2026-04-07
• DOI: 10.1136/bmjopen-2025-112219
• EISSN: 2044-6055
• ISSN: 2044-6055
• Language: English
• Keywords: Antibiotics; Systematic Review; Public health