Are antibiotics safe to use during breastfeeding?

Antibiotics and Breastfeeding Safety

Most commonly used antibiotics are safe during breastfeeding, with amoxicillin, amoxicillin/clavulanic acid, and cephalosporins classified as "compatible" with breastfeeding—the highest safety designation—and should be used as first-line agents when antibiotics are needed. 1, 2

First-Line Safe Antibiotics

Beta-Lactams (Preferred)

• Amoxicillin is classified as "compatible" with breastfeeding by the European Respiratory Society and American Academy of Dermatology, representing the highest level of safety designation. 1
• Amoxicillin/clavulanic acid (Augmentin) is recommended by the American Academy of Dermatology as safe and effective during breastfeeding, classified as FDA Category B and compatible with nursing. 1, 2
• Cephalosporins, including cephalexin and ceftriaxone, are considered "compatible" with breastfeeding and are appropriate first-line choices. 1
• The FDA drug label confirms that penicillins are excreted in human milk at low concentrations, but caution should be exercised. 3

Macrolides (Generally Safe with Timing Considerations)

• Azithromycin is classified as "probably safe" during breastfeeding, though ideally should be avoided during the first 13 days postpartum due to a very low risk of hypertrophic pyloric stenosis in exposed infants. 1
• This risk does not persist after 2 weeks, making macrolides safe for use beyond the early neonatal period. 1
• Erythromycin is suggested as safe, particularly for penicillin-allergic patients. 1

Other Compatible Antibiotics

• Metronidazole is suggested as safe during breastfeeding by the American Academy of Dermatology. 1
• Rifampin can be used with an approach similar to other patient populations. 1

Antibiotics Requiring Caution

Use Only When Necessary

• Clindamycin should be used with caution as it may increase the risk of GI side effects in the infant, including diarrhea, candidiasis, or rarely antibiotic-associated colitis. 1
• Topical clindamycin formulations result in significantly lower systemic absorption compared to oral administration, making them a safer option if clindamycin is specifically indicated. 1

Limited Duration Use

• Doxycycline use should be limited to 3 weeks maximum without repeating courses, and only if no suitable alternative is available. 1
• Short-term tetracycline use (3-4 weeks) is compatible with breastfeeding, but avoid longer courses due to potential tooth discoloration and bone growth suppression. 1

Special Populations to Avoid

• Co-trimoxazole should be avoided in premature babies, jaundiced infants, or those with G6PD deficiency. 1

Fluoroquinolones (Not First-Line)

• Fluoroquinolones should not be used as first-line treatment during breastfeeding, but if absolutely necessary, ciprofloxacin is the preferred fluoroquinolone due to its lower concentration in breast milk (two orders of magnitude lower than therapeutic infant doses). 1

Essential Infant Monitoring

What to Watch For

• All breastfed infants whose mothers are taking antibiotics should be monitored for gastrointestinal effects due to alteration of intestinal flora, though serious adverse events are rare. 1
• Monitor for mild diarrhea, gastroenteritis, or changes in stool pattern or consistency. 1, 2
• Watch for signs of candidiasis (thrush) in the infant's mouth. 1

Important Clinical Caveat

• Antibiotics in breast milk could potentially cause falsely negative cultures if the breastfed infant develops a fever requiring evaluation. 1, 2
• This means if your breastfed infant becomes febrile while you're on antibiotics, inform the pediatrician so they can interpret culture results appropriately. 1

Key Clinical Principles

Breastfeeding Should Continue

• The European Respiratory Society guidelines suggest that breastfeeding should not be interrupted when compatible antibiotics like amoxicillin are prescribed, as the benefits of continued breastfeeding outweigh the minimal risks of antibiotic exposure through breast milk. 1
• Continued breastfeeding during antibiotic treatment does not pose a risk to the infant and actually helps resolve conditions like mastitis. 4

Dosing Considerations

• Use the lowest effective dose for the shortest duration needed to minimize infant exposure while maintaining therapeutic efficacy. 2
• The small amounts of antibiotic in breast milk should not be considered therapeutic for the infant—if the baby develops an infection, they require their own appropriate dosing. 1

Safety Assumptions

• The safety profile of antibiotics during breastfeeding assumes full-term, healthy infants, standard recommended doses and durations, and exclusive breastfeeding. 1

Common Pitfalls to Avoid

• Do not unnecessarily discontinue breastfeeding when short courses of compatible antibiotics are prescribed, as there is no evidence of harmful effects in breastfeeding women. 1
• Avoid using amoxicillin/clavulanic acid in women at risk of pre-term delivery due to a very low risk of necrotizing enterocolitis in the fetus, but for breastfeeding after term delivery, it remains fully compatible and safe. 1
• Do not assume all antibiotics are unsafe—most commonly used antibiotics are considered compatible with breastfeeding. 5, 6
• Consult the NIH's LactMed database for the most current information on specific antibiotics if uncertainty exists. 1