What antibiotics are safe for breastfeeding mothers?

Safe Antibiotics for Breastfeeding Mothers

Most β-lactam antibiotics, including penicillins and cephalosporins, are considered safe during breastfeeding and should be used as first-line options when appropriate for the infection. 1

First-Line Safe Antibiotics

Penicillins

• Amoxicillin and amoxicillin/clavulanic acid are explicitly recommended as safe options for breastfeeding mothers requiring antibiotic therapy 2, 1
• Penicillins are considered first-line options with excellent safety profiles during lactation 1
• These agents have minimal transfer to breast milk and are classified as FDA Category B 2

Cephalosporins

• Cephalosporins, including cephalexin and ceftriaxone, are considered "compatible" with breastfeeding 2, 1
• First-generation cephalosporins are particularly recommended for skin and soft tissue infections in breastfeeding women 1
• Cephalosporins have minimal transfer to breast milk and limited impact on the nursing infant 1
• When choosing between cephalosporins, prefer those with shorter half-lives (e.g., cefotaxime 1.1 hours) over longer-acting agents (e.g., ceftriaxone 7.25 hours) to minimize infant accumulation 3

Safe Alternative Antibiotics

Macrolides

• Azithromycin is classified as "probably safe" during breastfeeding 2, 1
• Erythromycin is suggested as safe, particularly for penicillin-allergic patients 2, 1
• Important caveat: There is a very low risk of hypertrophic pyloric stenosis in infants exposed to macrolides during the first 13 days of breastfeeding, but this risk does not persist after 2 weeks 2, 4
• Macrolides should ideally be avoided in the first 13 days postpartum if possible 1
• Clarithromycin is present in human milk at less than 2% of the maternal weight-adjusted dose, with infant exposure estimated at 136 mcg/kg/day (less than 1% of pediatric dosing) 5

Other Safe Options

• Metronidazole is suggested as safe during breastfeeding 2, 1
• Rifampin can be used with an approach similar to other patient populations 2, 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 2, 1, 4
• If clindamycin is necessary (e.g., for MRSA coverage), close monitoring of the infant for diarrhea and gastrointestinal symptoms is essential 2

Limited Duration Use

• Doxycycline use should be limited to 3 weeks maximum without repeating courses; use only if no suitable alternative is available 2, 1
• Tetracyclines generally should be avoided due to potential impacts on infant development 4

Antibiotics to Avoid

Based on pregnancy data that extends to lactation considerations:

• Fluoroquinolones should not be used as first-line treatment during breastfeeding 6
• Tetracyclines (beyond the 3-week limit) should be avoided 6
• Aminoglycosides should not be used 6
• Trimethoprim-sulfamethoxazole (co-trimoxazole) should be avoided in premature babies, jaundiced infants, or those with G6PD deficiency 2

Clinical Decision-Making Algorithm

Step 1: Choose β-lactams first

• Start with amoxicillin, amoxicillin/clavulanic acid, or cephalexin for most infections 1

Step 2: For penicillin-allergic patients

• Use azithromycin or erythromycin (avoid in first 13 days postpartum if possible) 1, 4
• Consider cephalosporins if the penicillin allergy is not IgE-mediated 1

Step 3: For specific infections requiring broader coverage

• Metronidazole for anaerobic coverage 2, 1
• Clindamycin for MRSA (with infant GI monitoring) 4

Important Monitoring Considerations

Infant Surveillance

• All breastfed infants should be monitored for gastrointestinal effects due to alteration of intestinal flora 2
• Watch specifically for rash, diarrhea, loss of appetite, and somnolence 5
• Antibiotics in breast milk could potentially cause falsely negative cultures if the breastfed infant develops fever requiring evaluation 2

Timing of Administration

• Administer medication immediately following a breast feed to minimize infant exposure at peak milk drug concentrations 3
• Peak milk concentrations generally occur 1-2 hours following oral medication 3

Reassurance for Mothers

• Continued breastfeeding during antibiotic treatment is generally recommended and does not pose significant risks to the infant 1, 7
• Most antibiotics result in subtherapeutic concentrations in breast milk, with infant exposure typically less than 2% of maternal weight-adjusted doses 5, 8
• The highest assessed exposure as a percentage of infant therapeutic dose is for metronidazole at only 11% 8

Key Clinical Pitfalls to Avoid

• Do not unnecessarily discontinue breastfeeding when safe antibiotic alternatives exist 1, 9
• Do not use macrolides in the first 13 days postpartum unless absolutely necessary due to pyloric stenosis risk 2, 4
• Do not prescribe long-acting formulations when shorter half-life alternatives are available 3
• Do not forget to consult the NIH LactMed database for specific antibiotic safety information when needed 1, 4