Chlamydial infection
Second line
Macrolide antibiotic
ATC code: J01FA01 (Erythromycin)
Brand names
EryPed, Ery-Tab, Erythrocin
Erythromycin binds the 50S bacterial ribosomal subunit and blocks protein chain elongation. It is bacteriostatic against gram-positive cocci, atypical pathogens (Mycoplasma, Chlamydia, Legionella), and Bordetella pertussis. The drug is a moderate CYP3A4 inhibitor and raises concentrations of statins, cyclosporine, carbamazepine, and warfarin. Erythromycin prolongs the QT interval by blocking the hERG channel; torsades de pointes has been reported, especially with intravenous administration, hypokalaemia, and concomitant QT-prolonging drugs.
Second line
Treats urogenital chlamydia in pregnancy as an azithromycin alternative. AEMPS considers erythromycin ethylsuccinate safe in gestation.
Second line
Macrolide for atypical-pathogen community-acquired pneumonia (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella). SEIMC prefers azithromycin or clarithromycin for tolerability; erythromycin remains an alternative.
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FDA Category B. Erythromycin is the AEMPS and SEIMC first-line macrolide in pregnancy due to long-standing experience. The estolate ester is contraindicated because of maternal cholestatic hepatitis risk.
Compatible. Hale L1. Transfers into milk (RID about 2%); infant diarrhoea and candidiasis possible. AEMPS notes a rare association with infant pyloric stenosis after exposure during the first 2 weeks of life.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Erythromycin is evaluated for the following indications with varying evidence strength: Community-acquired pneumonia (evidence tier A), Chlamydial infection (evidence tier A). See the full indication matrix with dosing and citations above on this page.
Common side effects of Erythromycin (≥ 1 in 100): Nausea, vomiting, diarrhoea, abdominal cramps, Taste disturbance, Elevated transaminases, Ototoxicity with high IV doses. See the Safety section for uncommon and serious reactions.
FDA category B. FDA Category B. Erythromycin is the AEMPS and SEIMC first-line macrolide in pregnancy due to long-standing experience. The estolate ester is contraindicated because of maternal cholestatic hepatitis risk.
Compatible. Hale L1. Transfers into milk (RID about 2%); infant diarrhoea and candidiasis possible. AEMPS notes a rare association with infant pyloric stenosis after exposure during the first 2 weeks of life.
Erythromycin is contraindicated in: Hypersensitivity to macrolides; Severe hepatic impairment; Co-administration with astemizole, terfenadine, cisapride, pimozide, ergotamine, dihydroergotamine, lovastatin, simvastatin (QT prolongation and toxicity); Erythromycin estolate in pregnancy. Full list in the Safety section.