Is it safe to use Prozac (fluoxetine) while breastfeeding?

Prozac (Fluoxetine) Use During Breastfeeding

Fluoxetine can be used during breastfeeding, but sertraline is strongly preferred as first-line therapy due to its superior safety profile with minimal breast milk excretion and lower infant plasma concentrations. 1

Preferred Alternative: Sertraline First-Line

• Sertraline should be considered the first-choice SSRI for breastfeeding mothers because it provides infants with less than 10% of the maternal daily dose and has minimal excretion in breast milk. 1
• Paroxetine and sertraline are the most commonly prescribed antidepressants during breastfeeding, with both considered suitable first-line agents. 1
• For mothers already taking sertraline, continue the medication and breastfeed rather than discontinuing either, as untreated maternal depression poses significant risks to the mother-infant dyad. 1

Fluoxetine Safety Profile During Breastfeeding

Evidence of Excretion and Infant Exposure

• The FDA label states that fluoxetine is excreted in human milk and nursing while on Prozac is not recommended. 2
• One case report documented an infant who developed crying, sleep disturbance, vomiting, and watery stools while nursing, with infant plasma drug levels of 340 ng/mL fluoxetine and 208 ng/mL norfluoxetine. 2
• Breast milk concentrations range from 39-177 ng/mL when maternal plasma levels are 138-427 ng/mL. 3
• Approximately 10.8% of the maternal dose (adjusted per kg) is excreted in breast milk as fluoxetine equivalents. 4

Physiologic Effects on Infants

• Most infants (10 of 11 in one study) experienced little to no decline in platelet serotonin levels, suggesting minimal serotonin transporter blockade. 5
• However, one infant with measurable plasma fluoxetine levels showed a substantial decline in platelet serotonin to 40% of baseline, raising concern about meaningful drug exposure. 5
• In four studied cases, fluoxetine and norfluoxetine in infants' plasma were below detection limits, and all infants developed normally with no neurological abnormalities. 3

Clinical Decision Algorithm

If Patient Is Not Yet on an SSRI:

• Start sertraline 25-50 mg daily as first-line therapy, titrating slowly upward while monitoring the newborn. 1
• Use the lowest effective dose throughout treatment. 1

If Patient Is Already on Fluoxetine and Responding Well:

• Weigh the risks of switching medications (potential relapse, finding new effective dose) against continuing fluoxetine with close infant monitoring. 6
• Consider that switching from effective treatment should only occur after scrupulous evaluation of risks versus benefits. 6
• If continuing fluoxetine, implement enhanced monitoring protocols (see below). 6

If Patient Requires Switch from Fluoxetine:

• Transition to sertraline or citalopram as alternatives. 1
• Citalopram can be considered if sertraline is not tolerated or ineffective. 1

Monitoring Requirements for Fluoxetine During Breastfeeding

• Monitor infants for irritability, jitteriness, poor feeding, sleep disturbance, vomiting, and watery stools. 2, 6
• Pay particular attention if the infant was born premature or had low birth weight. 6
• Arrange early follow-up after initial hospital discharge for infants exposed to SSRIs. 1
• Monitor over the first week of life for signs of drug toxicity or withdrawal. 1

Timing Strategy to Minimize Infant Exposure

• When feasible, avoid breastfeeding at the time when antidepressant milk concentration is at its peak to reduce child exposure. 6
• Dose before the infant's longest sleep interval. 7

Critical Caveats

• Fluoxetine and norfluoxetine have substantially longer plasma half-lives compared to other SSRIs, increasing the potential for accumulation in infant plasma. 5
• Exclusively breastfed infants and those whose mothers have high plasma drug levels may be at higher risk for measurable infant plasma levels. 5
• The long-term neurodevelopmental consequences of SSRI exposure through breast milk remain unknown, though several reviews have not identified adverse neurodevelopmental outcomes. 1, 5
• Untreated maternal depression carries substantial documented risks including premature birth, decreased breastfeeding initiation, and harm to the mother-infant relationship. 1

Common Pitfall to Avoid

• Do not discontinue effective psychiatric treatment out of fear of medication exposure, as the risks of untreated maternal depression often outweigh theoretical medication risks. 1
• However, when initiating new treatment in a breastfeeding mother, prioritize sertraline over fluoxetine given the superior safety data. 1