Azithromycin therapy in hospitalized infants with acute bronchiolitis is not associated with better clinical outcomes: a randomized, double-blinded, and placebo-controlled clinical trial

To test the hypothesis that azithromycin reduces the length of hospitalization and oxygen requirement in infants with acute viral bronchiolitis (AB).We performed a randomized, double-blinded, placebo-controlled trial in southern Brazil, from 2009 to 2011. Infants (12 months of age) hospitalized with AB were recruited in 2 hospitals. Patients were randomized to receive either azithromycin or placebo, administered orally, for 7 days. At enrollment, clinical data were recorded and nasopharyngeal samples were collected for viral identification through immunofluorescence. Main outcomes were duration of oxygen requirement and length of hospitalization.One hundred eighty-four patients were included in the study (azithromycin 88 subjects, placebo 96 subjects). Baseline clinical characteristics and viral identification were not different between the groups studied. A virus was detected in 112 (63%) patients, and of those, 92% were positive for respiratory syncytial virus. The use of azithromycin did not reduce the median number of days of either hospitalization (P = .28) or oxygen requirement (P = .47).Azithromycin did not improve major clinical outcomes in a large sample of hospitalized infants with AB, even when restricting the findings to those with positive respiratory syncytial virus samples. Azithromycin therapy should not be given for AB because it provides no benefit and overuse increases overall antibiotic resistance.