What it's for (Indications)
- Fluoxetine is indicated for the treatment of Major Depressive Disorder (MDD), particularly in cases where sedation is not required; Obsessive-Compulsive Disorder (OCD); Bulimia Nervosa; and Panic Disorder.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | Fluoxetine should not be abruptly stopped; gradual dose reduction is necessary under medical supervision to prevent withdrawal symptoms. Dosage forms may require initial titration with other fluoxetine formulations for doses of 10-20 mg/day or doses other than 30 mg or 60 mg. For Major Depressive Disorder (MDD), adult initial dose is 20 mg/day in the morning, with a common target dose of 20 mg/day; doses can be increased up to 60 mg/day (or maximum studied 80 mg/day) if no response after several weeks, though no additional benefits may be seen above 20 mg/day for MDD. Pediatric initial dose for MDD is 10 to 20 mg/day. For Obsessive-Compulsive Disorder (OCD), adult initial dose is 20 mg/day in the morning, with a target range of 20 to 60 mg/day; pediatric initial dose is 10 mg/day, with a target range of 10 to 60 mg/day. For Bulimia Nervosa, the typical adult dose is 60 mg/day in the morning. For Panic Disorder, adult initial dose is 10 mg/day, with a target dose of 20 mg/day (maximum studied 60 mg/day). In older patients (above 65 years) or those with liver impairment, a recommended dose is 20 mg/day; caution is advised. |
Safety & Warnings
Common Side Effects
- Common side effects include nausea, indigestion, vomiting, fatigue, headache, dry mouth, increased sweating, loss of appetite, insomnia (trouble sleeping), sinusitis, decreased sexual drive/libido, delayed ejaculation, abnormal dreams, anxiety, dizziness, asthenia (muscle weakness), rash, convulsions/seizures, hypomania, mania, anorexia, sleep disorders, restlessness, disturbance in attention, dysgeusia (distortion of taste), somnolence (increased sleep), tremor, blurred vision, palpitations, QT prolongation, flushing, yawning, GI upset, allergic reactions, arthralgia (joint pain), urinary frequency, gynaecological bleeding, sexual dysfunction, chills, and weight changes (gain or loss).
- Severe adverse events include serotonin syndrome, bleeding disorders, erythema multiforme.
- In children and adolescents, specific side effects may include suicide-related behavior, mania, hypomania, epistaxis (nosebleeds), growth retardation, and decreased alkaline phosphatase.
Serious Warnings
- Black Box Warning: Antidepressants, including fluoxetine, increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. These studies did not show an increase in the risk of suicidal thoughts and behavior with antidepressant use in patients over age 24; there was a reduction in risk with antidepressant use in patients aged 65 and older. Close monitoring for suicidal ideation and behavior is crucial in all patients, especially at the beginning of therapy and during dose changes.
- Patients should be closely monitored for suicidal thoughts and behaviors, especially children, adolescents, and young adults, and during initiation of therapy or dose changes.
- Serotonin Syndrome is a serious risk.
- Allergic reactions and rash can occur.
- Screen patients for bipolar disorder and monitor for mania/hypomania.
- Seizures can occur, and caution is advised in patients with stable epilepsy or a history of seizure disorders.
- Altered appetite and weight changes (gain or loss) may occur, and patients with diabetes should be monitored carefully.
- There is an increased risk of bleeding, particularly when co-administered with other medications affecting hemostasis.
- Angle-closure glaucoma, narrow-angle glaucoma, and raised intraocular pressure are risks; screen patients for glaucoma.
- Hyponatremia may occur.
- Anxiety and insomnia can be side effects.
- QT prolongation and potential for Torsades de pointes are risks, and patients should report any heart symptoms; use with caution in patients with heart disease or risk factors.
- Potential for cognitive and motor impairment exists; patients should avoid driving or operating heavy machinery until they know how the drug affects them.
- Abrupt discontinuation can lead to withdrawal symptoms; fluoxetine should be tapered gradually under medical supervision.
- Inform the doctor of all medications (prescription, over-the-counter, herbal, vitamins), especially tramadol, diuretics, amoxapine, bromocriptine, and antibiotics, as they can interact.
- Inform the doctor of all pre-existing conditions including liver problems, kidney disease, immune system disorders, lupus, glaucoma, diabetes, and seizure disorders.
- Alcohol consumption should be limited or avoided.
- This medication can make patients sensitive to the sun; limit sun exposure and use protective measures.
- Use with caution in patients undergoing ECT.
- Monitor growth and pubertal development in children during and after treatment.
- A dose increase may be detrimental in patients who develop akathisia.
- Fluoxetine is a poor CYP2C19 metabolizer.
- Use cautiously in elderly patients, and withdraw gradually if adverse symptoms appear.
- Signs of overdose include confusion, agitation/restlessness, dilated pupils, muscle rigidity, heavy sweating, and diarrhea.
- Use during pregnancy can be unsafe, and the risk is undetermined; consult a doctor.
- Use in lactation is contraindicated or unsafe; consult a doctor.
How it Works (Mechanism of Action)
Although the exact mechanism of fluoxetine is unknown, it is presumed to be linked to its inhibition of central nervous system (CNS) neuronal uptake of serotonin.