Is it safe to take Duloxetine (Cymbalta) while breastfeeding?

Duloxetine Safety During Breastfeeding

Duloxetine is likely safe to use while breastfeeding as infant exposure is minimal, with relative infant doses less than 1% of the maternal dose. However, monitoring the infant for potential adverse effects is recommended.

Evidence on Duloxetine in Breastfeeding

Infant Exposure

• Duloxetine passes into breast milk but in very small amounts
• Relative infant dose (RID) is consistently reported to be less than 1% of the maternal dose 1, 2, 3, 4
• Specific measurements show:
  • 0.14% of maternal dose 3
  • 0.2-0.4% of maternal dose 2
  • 0.81% of maternal dose 1

Milk-to-Plasma Ratio

• The milk-to-plasma ratio is approximately 0.25, meaning breast milk concentrations are about one-fourth of maternal plasma levels 3
• This indicates limited transfer into breast milk

Infant Monitoring

• The FDA drug label recommends monitoring breastfed infants for 5:
  • Sedation
  • Poor feeding
  • Poor weight gain

Safety Considerations

Potential Adverse Effects

• While no significant adverse effects have been reported in breastfed infants exposed to duloxetine, the FDA label notes potential concerns including 5:
  • Respiratory distress
  • Cyanosis
  • Seizures
  • Temperature instability
  • Vomiting
  • Hypoglycemia
  • Altered muscle tone
  • Irritability

Case Reports

• Several case reports document use of duloxetine during breastfeeding without observed adverse effects in infants 1, 2, 6
• One case study followed an infant exposed to duloxetine during both pregnancy and breastfeeding with no adverse events noted 1

Practical Recommendations

Minimizing Infant Exposure

• Use the lowest effective maternal dose
• Consider timing breastfeeding to avoid peak maternal drug concentrations
• Monitor the infant carefully for any adverse effects

When to Consider Alternative Medications

• If the infant shows signs of:
  • Sedation
  • Poor feeding
  • Poor weight gain
  • Jitteriness
  • Vomiting or diarrhea

Conclusion

The available evidence suggests that duloxetine exposure through breast milk is minimal and likely safe for most infants. The benefits of breastfeeding generally outweigh the potential risks of duloxetine exposure through breast milk. However, careful monitoring of the infant is essential, particularly for signs of sedation, poor feeding, and poor weight gain as recommended in the FDA labeling.