Erythromycin

Pregnancy

No adverse effects of topical erythromycin have been observed in animal studies. Erythromycin crosses the placenta when taken orally, however, when applied topically, only a small fraction of erythromycin enters the bloodstream. 

Therefore, topical erythromycin can be safely used during pregnancy.

Category: B

Category A

Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Category B

Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

Category C

Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Category D

There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Category X

Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.

Breastfeeding

Excretion into human milk: Unknown 

Low levels of erythromycin are found in breast milk after oral intake which are unlikely to cause side-effects. It is unknown if topical erythromycin is found in breast milk.

Infants exposed to erythromycin may have a decreased appetite, diarrhea, rash, or somnolence (sleepiness) so monitor the infant. 

Do not apply erythromycin to the nipple area and make sure the infant’s skin does not come into contact with the areas of skin that have been treated with erythromycin.