clarithromycin during breastfeeding

All macrolide antibiotics can be used during breastfeeding with precautionary infant monitoring (1):

• treatment choice, duration and dose should be primarily based on clinical indications and in line with national and local antimicrobial policy, with suitability in breastfeeding as a secondary consideration
• reported side effects are not specific to a particular macrolide and are generally mild in nature

Clinical considerations (1,2):

• epidemiologic evidence indicates that the risk of hypertrophic pyloric stenosis in infants might be increased by use of maternal macrolides, especially in infants exposed in the first 2 weeks after birth
  • evidence suggest that this risk may be greater with erythromycin (1)
• infant effects
  • effect of the macrolide exposure on the infant needs to be considered
  • oral and gut microflora
    • exposure to antimicrobials can affect the infant’s natural balance of microflora
      • in rare cases, antibiotic exposure has disturbed this balance and caused gastrointestinal disturbances or candidiasis
        • effects are generally mild and resolve upon treatment discontinuation
          
          
• treatment of infant infections
  • is no conclusive information on whether the concentrations the infant is exposed to through breast milk are enough to be bactericidal or cause bacterial resistance
  • if the infant needs treatment themselves with a macrolide or other antibiotic, they should receive the appropriate infant therapeutic dose, regardless of concomitant exposure through breast milk
    
    
• hypersensitivity
  • is a theoretical risk of hypersensitivity in the infant after exposure to macrolides through breast milk
    • foetal exposure to antibiotics through the placenta may cause sensitisation
    • further exposure may result in allergic reactions, even from the negligible quantities seen in breast milk
    • as a precaution, the infant should be monitored for signs of hypersensitivity which includes rashes and breathing problems
      
      
• hypertrophic pyloric stenosis
  • is conflicting data regarding whether there is an increased risk of infantile hypertrophic pyloric stenosis from exposure to macrolides via breast milk (1)
  • some studies have noted an increased risk during the first 90 days of life, and especially in the first 2 weeks after birth (1)
    • a nationwide cohort study showed macrolide use in infants was associated with a strongly increased risk of infantile hypertrophic pyloric stenosis (IHPS), including a 30-fold increased risk with use during the first two weeks after birth and a lower, but significantly increased threefold risk with use on days 14 to 120 (2)
    • risk might be increased with erythromycin, although this may simply reflect greater use
    • note that other studies fail to confirm this association between breastfeeding and maternal macrolide antibiotic use and risk of hypertrophic pyloric stenosis (1)

Reference:

• NHS Specialist Pharmacy Service (March 21st 2024). Using macrolide antibiotics during breastfeeding
• Lund M, Pasternak B, Davidsen RB, Feenstra B, Krogh C, Diaz LJ, Wohlfahrt J, Melbye M. Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study. BMJ. 2014 Mar 11;348:g1908