Which macrolide is recommended for the treatment of whooping cough in infants under one month old?

The recommended macrolide for the treatment of whooping cough, or pertussis, in infants under one month old is azithromycin. This choice is preferred due to its safety profile and dosing convenience. Azithromycin is associated with a lower risk of gastrointestinal side effects compared to erythromycin and has a longer half-life, which facilitates less frequent dosing.

In infants under one month, safety is a crucial consideration. Erythromycin, though historically used, has been associated with increased risk of complications such as pyloric stenosis in young infants, leading to recommendations against its use in this age group. Clarithromycin is not typically used for this indication in very young infants either. Telithromycin, while a macrolide, is not approved for use in pediatrics and has limited indications.

Given these factors, azithromycin emerges as the preferred treatment option due to its efficacy against Bordetella pertussis and a more favorable side effect profile in infants.