What is the use of Fluoxetine (Selective Serotonin Reuptake Inhibitor - SSRI)?

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From the Guidelines

Fluoxetine is primarily used to treat major depressive disorder, obsessive-compulsive disorder, panic disorder, and other mental health conditions by increasing serotonin levels in the brain. The use of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is supported by evidence from studies such as 1, which highlights its effectiveness in treating various mental health conditions.

Key Points

  • Fluoxetine is FDA approved for major depressive disorder, OCD, bulimia nervosa, premenstrual dysphoric disorder, panic disorder, and bipolar disorder (in combination with olanzapine) [ 1 ].
  • The typical starting dose for adults with depression or anxiety disorders is 20 mg once daily, usually taken in the morning.
  • Treatment should continue for at least 6-12 months after symptom improvement to prevent relapse.
  • Common side effects include nausea, headache, insomnia, and sexual dysfunction, which often improve with time [ 1 ].
  • Full therapeutic effects may take 4-6 weeks to develop, so patience is important when starting treatment.
  • Fluoxetine has a long half-life (2-3 days), making it more forgiving if doses are occasionally missed compared to other SSRIs.
  • It should not be combined with MAO inhibitors, and caution is needed when using it with other medications that affect serotonin levels to avoid serotonin syndrome.
  • Abrupt discontinuation should be avoided; tapering is recommended when stopping treatment to minimize withdrawal symptoms.

Considerations

  • Black box warnings have been issued for treatment-emergent suicidality, particularly in adolescents and young adults [ 1 ].
  • Genetic variation, particularly in cytochrome P450 2D6 (CYP2D6) and cytochrome P450 2C19 (CYP2C19), may affect the metabolism of fluoxetine and other SSRIs [ 1 ].
  • Patients should be closely monitored for adverse effects, and treatment should be adjusted as needed to minimize risks and maximize benefits.

From the FDA Drug Label

CLINICAL PHARMACOLOGYPharmacodynamicsThe antidepressant, antiobsessive compulsive, and antibulimic actions of fluoxetine are presumed to be linked to its inhibition of CNS neuronal uptake of serotonin.

The use of Fluoxetine, a Selective Serotonin Reuptake Inhibitor (SSRI), is for the treatment of:

  • Major Depressive Disorder
  • Obsessive-Compulsive Disorder (OCD)
  • Bulimia Its mechanism of action is presumed to be linked to its inhibition of CNS neuronal uptake of serotonin 2.

From the Research

Uses of Fluoxetine

  • Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) with demonstrated efficacy in the treatment of major depressive episodes 3, 4, 5, 6, 7
  • It is effective in the treatment of obsessive-compulsive disorder (OCD) 3, 4, 5, 6
  • Fluoxetine has been evaluated for the treatment of various psychiatric conditions, including:
    • Anorexia nervosa 4
    • Bulimia nervosa 4, 5
    • Tourette's syndrome 4
    • Trichotillomania 4
    • Panic disorders 4, 7
    • Paraphilias and related conditions 4
    • Substance abuse, alcoholism, and cocaine abuse 4
    • Dysthymic disorder 4, 7
    • Fibrositis 4
    • Postanoxic action myoclonus 4
    • Pathologic jealousy 4
    • Personality disorder 4
    • Pseudobulbar affect 4
    • Social phobia 4, 7
    • Premenstrual dysphoric disorder 4, 7
  • Fluoxetine has also been used in the treatment of pain relief in certain diabetics, and migraine headache 4

Dosage and Administration

  • The optimal fluoxetine dose for OCD is 40 to 60 mg daily 3
  • The minimum treatment duration for OCD is 1 to 2 years 3
  • Efficacy should not be evaluated before 8 weeks to allow for onset of the therapeutic effects 3

Safety and Efficacy

  • Fluoxetine has a good safety profile, with adverse effects such as insomnia, headache, and diminished libido rarely leading to discontinuation of treatment 3, 5, 7
  • Fluoxetine is effective and well-tolerated in OCD, and is considered a first-line treatment for this condition 3, 5
  • Fluoxetine has demonstrated safety in pregnancy, and is not associated with an increased risk of suicide in controlled clinical trials 5, 7

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Fluoxetine: a review on evidence based medicine.

Annals of general hospital psychiatry, 2004

Research

Obsessive compulsive disorder, depression, and fluoxetine.

The Journal of clinical psychiatry, 1991

Research

Selective serotonin-reuptake inhibitors: an update.

Harvard review of psychiatry, 1999

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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