Four weeks of amoxycillin-clavulanate is no better than two weeks of the antibiotic to resolve cough by 28 days in children with protracted bacterial bronchitis (PBB), a trial suggests.

But the researchers say the results are not clear-cut, as the time to the next exacerbation of wet cough was four times longer (median 150 days vs 36 days) in the children who stayed on the antibiotics for a month.

Australian respiratory physicians set out to clarify the optimum duration of treatment, recruiting children aged between two months and 19 years with suspected PBB from EDs at hospitals in Perth, Darwin and Brisbane.

In total, 106 children (median age 1.7 years, median duration of cough 15.1-21.4 weeks) from four hospitals were randomised either to four weeks of amoxycillin-clavulanate (25-35mg/kg twice daily as oral suspension) or to two weeks on the antibiotic followed by two weeks of placebo.