Fluoxetine Oral: Dosing, Duration, and Precautions

Therapeutic action

Antidepressant, selective serotonin re-uptake inhibitor (SSRI).

Indications

• Major depression.
• Generalised anxiety.
• Severe post-traumatic stress disorder.

Forms and strengths

• 20 mg capsule.

Dose

Duration

• Major depression: at least 9 months. Discontinue gradually, for example half dose daily for 2 weeks then on alternate days for 2 weeks. If signs of relapse or withdrawal occur, increase the dose then decrease it more gradually.
• Generalised anxiety and severe post-traumatic stress disorder: 2 to 3 months after symptoms resolve. Discontinue gradually over at least 2 weeks.

Contra-indications, adverse effects, precautions

• Administer with caution and monitor use in patients with epilepsy, diabetes, hepatic impairment, severe renal impairment, history of gastrointestinal bleeding, bipolar disorders, suicidal ideation in young adults, or closed-angle glaucoma.
• May cause gastrointestinal disturbances, drowsiness, fatigue, headache, dizziness, seizures, sexual dysfunction, blurred vision, and hyponatraemia, especially in older patients.
• May cause anxiety, insomnia, agitation, aggressive behaviour, and suicidal ideation in young adults.
• Withdrawal symptoms are very frequent if discontinued abruptly.
• Avoid combination with aspirin, NSAIDs, and warfarin because of bleeding risk.
• Avoid serotonergic combinations with other SSRIs, tricyclic antidepressants, ondansetron, tramadol, and related drugs because of serotonin syndrome risk.
• Monitor combination with carbamazepine, phenytoin, risperidone, and drugs that lower seizure threshold.
• Avoid alcohol during treatment.
• Pregnancy: re-evaluate whether treatment is still necessary; if started during pregnancy, preferably use sertraline.
• Breast-feeding: avoid; consider switching to sertraline or paroxetine.