Terbinafine vs. Fluconazole Safety During Breastfeeding
Terbinafine is NOT safer than fluconazole during breastfeeding and should be avoided in lactating mothers. 1
Comparison of Safety Profiles
Fluconazole
- Safety during lactation: Considered compatible with breastfeeding by multiple authorities including the American Academy of Pediatrics and the Infectious Diseases Society of America 2
- Milk concentration: Approximately 85% of plasma concentration 2
- Infant exposure: Estimated daily infant dose is approximately 0.39 mg/kg/day, representing about 13% of the recommended pediatric dose for oropharyngeal candidiasis 3
- Clinical evidence: No adverse effects have been observed in breastfed infants whose mothers were taking fluconazole 2, 4
- Monitoring requirements: No special monitoring of the infant is required when the mother is taking fluconazole 2
Terbinafine
- Safety during lactation: Not recommended during breastfeeding 1
- Milk concentration: The ratio of terbinafine in milk to plasma is 7:1, indicating significant concentration in breast milk 1
- FDA recommendation: "Treatment with terbinafine is not recommended in nursing mothers" (explicit statement in FDA labeling) 1
- Clinical evidence: Limited data on effects in breastfed infants
Decision Algorithm for Antifungal Selection During Lactation
First-line option: Fluconazole
- Safe for use during breastfeeding
- No need to interrupt breastfeeding during treatment 4
- Effective against most Candida species
When to avoid fluconazole:
- Known hypersensitivity to fluconazole
- Significant hepatic impairment
- Concurrent medications with major interactions (rare during lactation)
Alternative options:
Important Clinical Considerations
Drug interactions: Terbinafine has fewer drug interactions than fluconazole, but this advantage is outweighed by its higher concentration in breast milk 6
Treatment duration: For persistent infections requiring prolonged therapy, fluconazole's established safety profile during lactation makes it preferable to terbinafine 4
Common pitfall: Assuming that FDA pregnancy category B (terbinafine) means safety during lactation. The milk-to-plasma ratio is the critical factor, which is significantly higher for terbinafine (7:1) 1
Special situations: For dermatophyte infections that typically require terbinafine, consider:
- Delaying treatment until after lactation if clinically appropriate
- Using topical antifungals when possible
- Using fluconazole as an alternative, though it may be less effective against certain dermatophytes 7
In conclusion, based on the available evidence, fluconazole is the safer choice for breastfeeding mothers requiring systemic antifungal therapy, while terbinafine should be avoided during lactation due to its high concentration in breast milk and explicit contraindication in the FDA labeling.