Can fluoxetine (selective serotonin reuptake inhibitor) affect fertility?

Impact of Fluoxetine on Fertility

Yes, fluoxetine can negatively affect fertility in both men and women through various mechanisms that impact reproductive hormones and organs. 1, 2, 3

Effects on Male Fertility

Fluoxetine can impact male fertility through several mechanisms:

• Testicular changes: Research shows that fluoxetine exposure can reduce testicular weight (by 16%), epididymal weight (by 28%), and seminal gland weight (by 18%) 1
• Reduced spermatogenesis: Long-term fluoxetine use can cause significant decreases in:
  • Sperm motility and density
  • Volume of seminiferous epithelium (reduced by 17%)
  • Total volume of Leydig cells (reduced by 30%)
  • Daily sperm production (reduced by 18%) 1, 3
• Hormonal disruption: Fluoxetine can significantly decrease testosterone and FSH levels, which are critical for normal sperm production 3

Effects on Female Fertility

Fluoxetine can affect female fertility through:

• Disruption of estrous/menstrual cycles: High doses of fluoxetine can interrupt normal reproductive cycles within days of starting treatment 2
• Ovarian effects: Treatment can lead to fewer corpus luteum and antral follicles 2
• Altered estrogen signaling: Fluoxetine can upregulate estrogen receptors but paradoxically decrease estrogen signaling, affecting uterine weight and function 2
• Reduced conception rates: Women taking antidepressants, including fluoxetine, may have reduced probability of conceiving naturally (adjusted fecundability ratio of 0.66) 4

Clinical Considerations

When prescribing fluoxetine:

1. For patients trying to conceive:

   • Consider alternative treatments with less impact on fertility
   • If fluoxetine is necessary, use the lowest effective dose
   • Monitor reproductive parameters in patients concerned about fertility

2. For patients with specific conditions:

   • Premature ejaculation: Fluoxetine is actually used therapeutically for this condition, with delayed ejaculation being a beneficial side effect 5
   • Breast cancer patients on tamoxifen: Avoid fluoxetine as it inhibits CYP2D6, potentially reducing tamoxifen's efficacy 5, 6

3. Special populations:

   • Cancer survivors: SSRIs including fluoxetine may be used to treat ejaculation problems in male cancer survivors 5
   • Menopausal women: Fluoxetine may be used for vasomotor symptoms but at lower doses than those used for depression 6

Risk Mitigation

• Dose considerations: Fertility effects appear to be dose-dependent; lower doses may have less impact 1
• Temporary effects: Some fertility parameters may recover after discontinuation of the medication
• Monitoring: For patients concerned about fertility, consider periodic assessment of reproductive hormones
• Alternative medications: For patients actively trying to conceive, consider antidepressants with potentially less impact on fertility

Common Pitfalls

• Underreporting of sexual dysfunction: Sexual side effects are reported by only 14% of patients spontaneously but affect up to 58% when specifically asked 7
• Delayed recognition: Fertility impacts may not be immediately apparent and could be overlooked
• Assuming reversibility: While some effects may be reversible upon discontinuation, long-term use may cause more persistent changes 3
• Ignoring female fertility effects: Much research focuses on male fertility, but women's fertility is also significantly affected 2, 4

When fertility is a concern, careful consideration of the risks and benefits of fluoxetine is essential, with potential consideration of alternative treatments or dose adjustments when appropriate.