A commonly used antibiotic “is not likely to help” when prescribed to children with chest infections, a study suggests.

Researchers said that unless doctors suspect pneumonia, they should avoid prescribing amoxicillin for treating chest infections in children.

A new study, published in The Lancet, examined the effect of the drug on 432 children aged between six months and 12 years who had a chest infection and attended GP surgeries across England and Wales between 2016 and 2020.

Half of the children were given amoxicillin and half were given a placebo.

The study, led by researchers from the University of Southampton and supported by centres at the universities of Bristol, Oxford and Cardiff, tracked the children to measure the duration of symptoms until children were well again.

Researchers also assessed symptom diaries filled out by patients.

The average duration of symptoms was similar between both groups – five days in the group who received antibiotics and six days in the group who received the fake medication.

The researchers judged that amoxicillin does not provide a “clinically important benefit” for symptom duration among children presenting with uncomplicated chest infections.

The authors concluded: “Amoxicillin for uncomplicated chest infections in children is unlikely to be clinically effective either overall or for key subgroups in whom antibiotics are commonly prescribed.

“Unless pneumonia is suspected, clinicians should provide safety-netting advice but not prescribe antibiotics for most children presenting with chest infections.”

Paul Little, professor of primary care research at the University of Southampton and the study’s lead author, said: “Children given amoxicillin for chest infections where the doctor does not think the child has pneumonia do not recover much more quickly.

“Indeed, using amoxicillin to treat chest infections in children not suspected of having pneumonia is not likely to help and could be harmful.”

Co-author Alastair Hay, professor of primary care at the University of Bristol, said: “Our results suggest that unless pneumonia is suspected, clinicians should provide ‘safety-netting’ advice – such as explaining what illness course to expect and when it would be necessary to re-attend – but not prescribe antibiotics for most children presenting with chest infections.”