How long before sexual activity should fluoxetine (selective serotonin reuptake inhibitor) be taken to treat premature ejaculation?

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Last updated: June 13, 2025View editorial policy

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From the Guidelines

Fluoxetine should be taken daily, rather than as an on-demand treatment before sexual activity, to effectively treat premature ejaculation. The recommended dosage ranges from 20-40 mg daily 1. Unlike some other treatments for premature ejaculation that can be taken a few hours before intercourse, SSRIs like fluoxetine require consistent daily use to build up effective levels in the body. This approach works because SSRIs increase serotonin levels in the brain and spinal cord, which helps delay ejaculation by modulating the ejaculatory reflex.

Key Points to Consider

  • On-demand administration of fluoxetine 3-6 hours before intercourse is modestly efficacious and well tolerated but is associated with substantially less ejaculatory delay than daily treatment in most studies 1.
  • Daily treatment with fluoxetine is effective in delaying ejaculation, with a typical delay in ejaculation time 1.
  • Patients should be aware that full therapeutic effects may take 2-4 weeks to develop, and side effects like decreased libido, erectile dysfunction, or gastrointestinal issues can occur 1.
  • It's essential to take fluoxetine as prescribed by a healthcare provider and not adjust dosing without medical guidance, as abrupt discontinuation can cause withdrawal symptoms 1.

Important Considerations

  • Treatment with SSRIs should be avoided in men with a history of bipolar depression due to the risk of mania 1.
  • The use of off-label SSRIs is favored over the TCA clomipramine because of a better side effect profile 1.
  • A systematic review did not identify a significant difference in suicidal ideation in adult men treated with anti-depressants versus placebo 1.

From the Research

Dosage and Timing of Fluoxetine for Premature Ejaculation

  • The optimal timing for taking fluoxetine before sexual activity to treat premature ejaculation is 2-3 hours, as indicated in a study published in 2007 2.
  • The dosage of fluoxetine used in this study was 20 mg daily for 4 weeks, and then 20 mg as needed 2-3 hours before sexual activity for 4 months.
  • Another study published in 2008 used a combination of tadalafil and fluoxetine, with fluoxetine 90 mg taken once a week and tadalafil 20 mg taken within a 36-hour frame of intended sexual intercourse 3.
  • The study found that the combination of tadalafil and fluoxetine significantly increased the intravaginal ejaculatory latency time (IELT) in men with lifelong premature ejaculation.

Efficacy of Fluoxetine in Treating Premature Ejaculation

  • Fluoxetine has been shown to be effective in treating premature ejaculation, with significant improvements in IELT, ejaculatory control, and distress levels for both men and their partners 4.
  • A study published in 1999 compared the efficacy and side effects of sertraline and fluoxetine in the treatment of premature ejaculation, and found that both medications had similar efficacy and side effects 5.
  • Another study published in 1996 discussed the use of antidepressants, including fluoxetine, in the treatment of premature ejaculation, and found them to be a safe and effective treatment option 6.

Side Effects and Compliance

  • Common side effects of fluoxetine include nausea, headache, insomnia, and dizziness 5.
  • A study published in 2019 found that compliance with fluoxetine use in men with primary premature ejaculation was poor, with dropout rates of 56% and 72% at 6 and 12 months, respectively 4.
  • Predictors of continued use of fluoxetine at 12 months included high partner distress, being unpartnered, and having a post-treatment IELT ≥5 minutes 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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