What antibiotics are safe for a breastfeeding mother to use?

Antibiotics Safe for Breastfeeding

Penicillins (amoxicillin, amoxicillin-clavulanate) and cephalosporins (cephalexin, ceftriaxone, cefuroxime) are the safest first-line antibiotics for breastfeeding mothers and should be used preferentially—these β-lactam antibiotics are classified as "compatible" with breastfeeding and do not require interruption of nursing. 1, 2, 3

First-Line Safe Antibiotics

β-Lactam Antibiotics (Preferred)

• Amoxicillin is classified as "compatible" with breastfeeding, representing the highest safety tier, and is present in breast milk only at low concentrations with minimal infant exposure. 2, 3

• Amoxicillin-clavulanate (Augmentin) is explicitly recommended as safe and effective, classified as FDA Category B and compatible with nursing—this should be your go-to combination agent. 1, 2, 3

• Cephalosporins including cephalexin (first-generation), ceftriaxone (third-generation), and cefuroxime are all classified as "compatible" with breastfeeding and have minimal transfer to breast milk. 1, 3

• All β-lactam antibiotics are routinely used in breastfeeding mothers with no requirement to stop nursing. 2

Macrolides (Safe Alternatives, Especially for Penicillin Allergy)

• Azithromycin is classified as "probably safe" during breastfeeding and serves as an excellent alternative for penicillin-allergic patients. 1, 3

• Azithromycin should ideally be avoided during the first 13 days postpartum due to a very low risk of infantile hypertrophic pyloric stenosis (IHPS), though this risk does not persist after 2 weeks. 3

• Erythromycin is suggested as safe, particularly for penicillin-allergic patients, but carries the same early postpartum caution as azithromycin. 1, 3

• For infants younger than 1 month, azithromycin is preferred over erythromycin because it has not been linked to IHPS. 3

Other Safe Options

• Metronidazole is considered safe during breastfeeding and can be added for enhanced anaerobic coverage when needed. 1, 3

• Rifampin can be used with an approach similar to other patient populations. 1, 3

Antibiotics Requiring Caution

Clindamycin (Use with Caution)

• Oral clindamycin should be used with caution as it may increase the risk of GI side effects in the infant, including diarrhea, candidiasis (thrush, diaper rash), or rarely antibiotic-associated colitis. 1, 3, 4

• The FDA drug label confirms that clindamycin appears in human breast milk at concentrations of less than 0.5 to 3.8 mcg/mL and has the potential to cause adverse effects on the infant's gastrointestinal flora. 4

• Topical clindamycin formulations result in significantly lower systemic absorption and are a safer option if clindamycin is specifically indicated. 3

• If oral clindamycin is required, it is not a reason to discontinue breastfeeding, but an alternate drug (such as amoxicillin-clavulanate) may be preferred. 4

Tetracyclines (Limited Use Only)

• Doxycycline use should be limited to a maximum of 3 weeks without repeating courses, and only if no suitable alternative is available. 1, 3

• Short-term tetracycline use (3-4 weeks) is compatible with breastfeeding, but longer courses should be avoided due to potential tooth discoloration and bone growth suppression in the infant. 3

Antibiotics to Avoid

• Fluoroquinolones (ciprofloxacin, levofloxacin) should not be used as first-line treatment during breastfeeding—if absolutely necessary, ciprofloxacin is the preferred fluoroquinolone due to its lower concentration in breast milk. 1, 3

• Aminoglycosides should not be used during breastfeeding due to potential risks to the infant. 1

• Co-trimoxazole should be avoided in premature infants, jaundiced babies, or those with G6PD deficiency. 3

Clinical Decision Algorithm

1. Start with amoxicillin or amoxicillin-clavulanate as first-line therapy for most infections requiring antibiotics in breastfeeding mothers. 1, 2, 3

2. If penicillin allergy exists, use azithromycin or erythromycin as safe alternatives (avoid in first 13 days postpartum if possible). 1, 3

3. For cephalosporin needs, cephalexin (first-generation) or ceftriaxone/cefuroxime (third-generation) are all compatible options. 1, 3

4. For infections requiring anaerobic coverage, add metronidazole to the regimen. 1, 3

5. Avoid clindamycin as first-line when safer alternatives are available; if used, monitor infant closely for GI effects. 1, 3, 4

6. Reserve doxycycline only when no other suitable alternative exists, limiting use to 3 weeks maximum. 1, 3

Infant 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. 2, 3

• Antibiotics in breast milk may cause falsely negative bacterial cultures if the infant develops fever and requires evaluation. 3

• Parents should be advised to watch for signs of IHPS (projectile vomiting, dehydration) if macrolides are used in the early postpartum period, though the absolute risk remains very low. 3

• The quantity of antibiotic transferred via breast milk is not therapeutic for the infant—any infant infection requires a separate, appropriate dosage. 3

Common Pitfalls to Avoid

• Do not unnecessarily discontinue breastfeeding when prescribing penicillins or cephalosporins—evidence consistently shows that the benefits of continued nursing outweigh the minimal risk of infant exposure. 2, 3

• Do not use oral clindamycin as first-line therapy when safer alternatives like amoxicillin-clavulanate are available. 1, 3

• Do not prescribe fluoroquinolones or tetracyclines as first-line therapy given the availability of safer β-lactam alternatives. 1, 3

• Consult the NIH LactMed database for the most current information on specific antibiotic safety during lactation. 1, 2, 3