Is fluoxetine (Prozac) safe to use during breastfeeding?

Fluoxetine Safety During Breastfeeding

Fluoxetine (Prozac) should be used with caution during breastfeeding due to its excretion in breast milk and potential impact on infant growth, with alternative SSRIs like sertraline or paroxetine being preferred first-line options for breastfeeding mothers. 1

Excretion in Breast Milk

• Fluoxetine is excreted in human breast milk, with documented concentrations in milk and detectable levels in infant plasma 1
• In one case report, breast milk concentration of fluoxetine plus norfluoxetine was 70.4 ng/mL while the mother's plasma concentration was 295.0 ng/mL 1
• Fluoxetine has a long half-life and its active metabolite norfluoxetine has been found in measurable quantities in plasma of nursing infants 2

Potential Risks to Breastfed Infants

• Adverse effects have been reported in some breastfed infants, including:

  • Crying, sleep disturbance, vomiting, and watery stools 1
  • Reduced weight gain in infants - a study showed infants breastfed by mothers taking fluoxetine had growth curves significantly below those of infants whose mothers did not take the medication (average deficit of 392g between 2 weeks and 6 months) 3

• One study found that while mothers experienced marked declines in platelet serotonin levels during fluoxetine treatment, most infants showed little to no change in their serotonin levels when exposed through breast milk 2

  • However, one infant with measurable plasma fluoxetine levels showed a substantial decline in serotonin to 40% of baseline 2

Clinical Recommendations

• If treatment with an SSRI is needed during the postpartum period, fluoxetine should not be the first alternative due to its higher excretion into breast milk compared to other SSRIs 4

• Sertraline and paroxetine are considered safer first-line options for breastfeeding mothers due to lower infant exposure 5

• If a mother is already stabilized on fluoxetine:

  • Monitor the infant for potential adverse effects including:
    • Vomiting, diarrhea, jitteriness, irritability, poor feeding, and sleep disturbances 1
    • Track infant weight gain at regular intervals 3

• High doses of fluoxetine should be used with particular caution in breastfeeding mothers 4

Risk-Benefit Assessment

• When the use of an SSRI is clearly indicated in a breastfeeding woman with significant depression, the positive effects of breastfeeding generally outweigh the risks of medication exposure to the infant 4
• The decision to use fluoxetine while breastfeeding should consider:
  • Severity of maternal depression
  • Prior response to specific antidepressants
  • Mother's commitment to breastfeeding
  • Availability of alternative medications with better safety profiles 2

Monitoring Recommendations

• If fluoxetine is used during breastfeeding:
  • Observe infant for signs of poor feeding, irritability, sleep disturbances, and gastrointestinal symptoms 1
  • Monitor infant weight gain closely, particularly in situations where weight gain is already of concern 3
  • Consider measuring infant plasma drug levels if concerns arise about excessive exposure or if adverse effects are observed 2