“For many years, the standard regimen for the treatment of pertussis in children has been administration of oral erythromycin. Recent studies have demonstrated equal efficacy and improved tolerability of other macrolides, such as azithromycin. (8) Azithromycin is associated with fewer adverse gastrointestinal events, may be dosed once daily, and does not inhibit the cytochrome P450 system, and therefore may be preferable. In addition, erythromycin has been associated with an increased risk of pyloric stenosis when administered to infants in the first 2 weeks after birth. (9)”

That’s the CDC’s link.  I read the emedicine recs, but they are based on studies from ’96 and ’82.  Practically speaking, I have never used erythro in practice.  The motility SEs of erythro are not pleasant, and it’s 4x daily.  Yikes.

TBH, I seriously doubt that the ABP would offer both erythro and azithro as answer choices.

Having said that, here are some additional thoughts:

1. If the child is < 1 mo of age, choose Azithromycin. Good consensus for this given the risks of pyloric stenosis

2. If the child is 1 – 6 mo of age, use “any macrolide.” Keep in mind that azithromycin and clarithromycin aren’t FDA approved for children less than 6 mo of age. I’d choose erythromycin

3. If the child is 6 mo or older, flip a coin. Compliance or reliability issues? Family history of pyloric stenosis? ANY other reason to avoid erythromycin? Choose Azithromycin.

but… I seriously doubt they’d make you choose. You’d probably only be given one macrolide choice.

hope that helps,

– ag