What antibiotics (Abx) are safe for a breastfeeding mother to use?

Safe Antibiotics During Breastfeeding

Amoxicillin and amoxicillin/clavulanic acid are the first-line safe antibiotics for breastfeeding mothers, classified as "compatible" with breastfeeding by the European Respiratory Society and American Academy of Dermatology, representing the highest safety designation. 1, 2, 3

First-Line Safe Antibiotic Options

Beta-Lactams (Preferred)

• Amoxicillin is explicitly classified as "compatible" with breastfeeding and should be your first choice for most infections. 1, 2
• Amoxicillin/clavulanic acid (Augmentin) is FDA Category B and classified as "compatible" with breastfeeding, making it safe and effective when broader coverage is needed. 1, 3
• Cephalosporins, including cephalexin, ceftriaxone, and ceftazidime, are all classified as "compatible" and represent excellent alternatives, particularly for penicillin-allergic patients. 1, 2

Macrolides

• Azithromycin is classified as "probably safe" but should ideally be avoided during the first 13 days postpartum due to a very low risk of hypertrophic pyloric stenosis in exposed infants; after 2 weeks, this risk does not persist. 1, 2
• Erythromycin is suggested as safe, particularly for penicillin-allergic patients. 1

Other Safe Options

• Metronidazole is suggested as safe during breastfeeding. 1
• Rifampin can be used with an approach similar to other patient populations. 1

Antibiotics Requiring Caution

Use With Monitoring

• 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, 4
• The FDA drug label confirms that clindamycin appears in breast milk at concentrations of less than 0.5 to 3.8 mcg/mL, and while breastfeeding need not be discontinued, an alternate drug may be preferred. 4
• If clindamycin is specifically indicated, topical formulations result in significantly lower systemic absorption and are safer than oral administration. 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, 2
• Short-term tetracycline use (3-4 weeks) is compatible with breastfeeding, but longer courses risk tooth discoloration and bone growth suppression in infants. 1, 2

Special Populations to Avoid

• Co-trimoxazole should be avoided in premature infants, jaundiced babies, or those with G6PD deficiency. 1, 2
• Fluoroquinolones should not be used as first-line treatment, but if absolutely necessary, ciprofloxacin is the preferred fluoroquinolone due to its lower concentration in breast milk. 1

Essential Monitoring Considerations

• All breastfed infants whose mothers are taking antibiotics should be monitored for gastrointestinal effects (diarrhea, gastroenteritis) due to alteration of intestinal flora, though serious adverse events are rare. 1, 2, 3
• Watch for changes in stool pattern or consistency, particularly with amoxicillin/clavulanic acid. 2, 3
• Antibiotics in breast milk could potentially cause falsely negative cultures if the breastfed infant develops fever requiring evaluation. 1, 3

Clinical Decision Algorithm

1. Start with amoxicillin for uncomplicated infections (respiratory, skin, dental). 1, 2
2. Use amoxicillin/clavulanic acid if broader coverage is needed or if treatment with amoxicillin alone fails. 1, 2, 3
3. Switch to cephalosporins (cephalexin or ceftriaxone) if penicillin allergy or treatment failure occurs. 1, 2
4. Consider azithromycin after 2 weeks postpartum if atypical coverage is needed. 1, 2
5. Use metronidazole for anaerobic coverage when necessary. 1

Common Pitfalls to Avoid

• Do not discontinue breastfeeding unnecessarily—most antibiotics used for common infections are compatible with continued nursing. 1, 2
• Do not use amoxicillin/clavulanic acid in women at risk of pre-term delivery due to a very low risk of necrotizing enterocolitis, but for breastfeeding after term delivery, it remains fully compatible and safe. 1
• Use the lowest effective dose for the shortest duration to minimize infant exposure while maintaining therapeutic efficacy. 2, 3
• 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