Certain Antibiotics Raise Pyloric Stenosis Risk in Infants

US Pharm. 2015;40(3):5.

Bethesda, MD—Erythromycin and azithromycin can increase the risk of pyloric stenosis in young infants, although the overall risk is small (two infants per 1,000). The association was strongest when exposure occurred in the first 2 weeks of life, but persisted to a lesser degree in those aged 2 to 6 weeks. An analysis of records of >1 million children revealed that >2,400 infants developed pyloric stenosis and that >6,700 infants had received azithromycin or erythromycin. Erythromycin use in the first 2 weeks of life was associated with a 13 times higher increased risk; the risk with azithromycin use was eight times higher. The risk in infants aged 2 to 6 weeks was four times higher and three times higher, respectively.