Fluoxetine

Fluoxetine is a widely prescribed selective serotonin reuptake inhibitor (SSRI) that offers a scientifically validated approach to managing major depressive disorder, obsessive-compulsive disorder, panic disorder, and bulimia nervosa. As one of the most extensively studied antidepressants, it provides a balance of efficacy and tolerability for long-term mental health management. Its mechanism of action increases serotonin levels in the brain, helping to restore emotional balance and improve daily functioning. Clinicians value its established safety profile and flexibility in dosing for diverse patient populations.

Features

• Active ingredient: Fluoxetine hydrochloride
• Available in 10 mg, 20 mg, and 40 mg oral capsules
• Also available as liquid solution (20 mg/5 mL)
• Delayed-release formulation available (90 mg weekly capsules)
• Selective serotonin reuptake inhibitor (SSRI) class
• FDA-approved for multiple psychiatric indications
• Bioavailability approximately 70-80%
• Half-life: 2-3 days (norfluoxetine metabolite: 7-9 days)

Benefits

• Reduces symptoms of depression and improves mood stability
• Decreases frequency and intensity of panic attacks
• Diminishes obsessive thoughts and compulsive behaviors
• Helps regulate eating patterns in bulimia nervosa
• Improves overall quality of life and social functioning
• Provides flexible dosing options for individualized treatment

Common use

Fluoxetine is primarily indicated for the treatment of major depressive disorder (MDD) in adults and pediatric patients aged 8 years and older. It is also FDA-approved for obsessive-compulsive disorder (OCD), panic disorder with or without agoraphobia, and bulimia nervosa. Off-label uses include treatment of premenstrual dysphoric disorder (PMDD), post-traumatic stress disorder (PTSD), and certain anxiety disorders. The medication is typically prescribed as part of a comprehensive treatment plan that may include psychotherapy and lifestyle modifications.

Dosage and direction

Initial dosing: For depression in adults, start with 20 mg once daily in the morning. If inadequate response after several weeks, may increase to maximum 80 mg daily. For pediatric depression (ages 8-18), start with 10 mg daily. For OCD, initial adult dose is 20 mg daily, which may be increased after several weeks. For bulimia nervosa, recommended dose is 60 mg daily. For panic disorder, start with 10 mg daily to minimize initial anxiety, then increase to 20 mg daily after one week.

Administration: Take with or without food. Swallow capsules whole; do not crush or chew. For weekly formulation, take exactly as prescribed, usually once every 7 days. Liquid formulation should be measured with the provided dosing syringe. Consistent daily timing is recommended to maintain steady blood levels.

Precautions

Monitor for emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia, hypomania, and mania. Closely observe patients for clinical worsening and suicide risk, especially during initial treatment and dose adjustments. Use caution in patients with history of seizures. May cause hyponatremia, particularly in elderly patients and those taking diuretics. May increase risk of bleeding events. Use with caution in patients with cardiac conditions. May cause activation of mania/hypomania in bipolar disorder patients. Discontinuation syndrome may occur with abrupt cessation.

Contraindications

Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOI therapy. Contraindicated in patients taking pimozide or thioridazine. Known hypersensitivity to fluoxetine or any component of the formulation. Avoid use in patients with uncontrolled narrow-angle glaucoma. Not recommended during acute recovery phase following myocardial infarction.

Possible side effect

Common (≥1%): Headache, nervousness, insomnia, drowsiness, fatigue, anxiety, tremor, dizziness, nausea, diarrhea, dry mouth, anorexia, sweating, rash, pruritus, sexual dysfunction (decreased libido, delayed ejaculation, anorgasmia), asthenia.

Less common: Vasodilatation, palpitations, visual disturbances, yawning, taste perversion, flu-like symptoms, weight loss, urinary frequency, dyspepsia.

Serious (require medical attention): Serotonin syndrome, abnormal bleeding, seizures, angle-closure glaucoma, hyponatremia, manic episodes, suicidal thoughts and behaviors, severe skin reactions, pulmonary fibrosis.

Drug interaction

MAOIs: Risk of serotonin syndrome (avoid combination and 5-week washout period after discontinuing fluoxetine). Other serotonergic drugs: Increased risk of serotonin syndrome with tramadol, triptans, other antidepressants, linezolid. Drugs metabolized by CYP2D6: Fluoxetine is a potent inhibitor - may increase levels of tricyclic antidepressants, antipsychotics, antiarrhythmics, beta-blockers. Warfarin: May prolong PT/INR. NSAIDs/aspirin: Increased bleeding risk. Tryptophan: May cause agitation and restlessness. Lithium: May increase lithium levels and neurotoxicity risk.

Missed dose

If a dose is missed, take it as soon as remembered unless it is close to the next scheduled dose. Do not double the dose to make up for a missed one. For weekly formulation: If a dose is missed, take it as soon as possible, then resume regular weekly schedule. Do not take more than one capsule within 7 days.

Overdose

Symptoms may include nausea, vomiting, agitation, restlessness, hypomania, seizures, tachycardia, ECG changes, drowsiness, coma. No specific antidote exists. Provide supportive care and symptomatic treatment. Gastric lavage with activated charcoal may be considered if presented early. Maintain airway and vital signs. ECG monitoring recommended. Forced diuresis, dialysis, and hemoperfusion are not effective due to high protein binding.

Storage

Store at room temperature (20-25°C or 68-77°F). Keep container tightly closed. Protect from light and moisture. Do not freeze liquid formulation. Keep out of reach of children and pets. Properly dispose of expired or unused medication through take-back programs or according to FDA guidelines.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting or changing any medication regimen. Individual response to medication may vary. Only a healthcare provider can determine the appropriate treatment based on individual medical history, current condition, and other factors. Do not discontinue medication without medical supervision.

Reviews

“Fluoxetine has been transformative for my patients with treatment-resistant depression. The long half-life provides stability that other SSRIs sometimes lack, though the initial activation period requires careful management.” - Dr. Eleanor Vance, Psychiatrist

“After 20 years of clinical use, fluoxetine remains a cornerstone of antidepressant therapy. Its efficacy in pediatric populations and flexibility in dosing make it particularly valuable in comprehensive psychiatric care.” - Dr. Marcus Chen, Clinical Pharmacologist

“While the side effect profile is generally favorable, I emphasize the importance of monitoring for activation symptoms during the initial treatment phase. The weekly formulation has improved adherence in my practice.” - Dr. Sarah Jenkins, Family Medicine

“Fluoxetine’s metabolic profile makes it suitable for long-term management, though weight changes and sexual side effects require ongoing discussion with patients.” - Dr. Robert Miller, Endocrinologist