Fluoxetine

Class & Mechanism

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). It increases serotonin availability in the synaptic cleft by blocking its reuptake into the presynaptic neuron. Its anti-obsessional properties make it useful for obsessive-compulsive symptoms.

Indications

• Obsessive type of morbid-jealousy — where the jealous thoughts are intrusive, repetitive, and recognised by the patient as irrational (as opposed to the delusional type where antipsychotics such as risperidone are used).
• Depression.
• Obsessive-compulsive disorder (OCD).
• Bulimia nervosa.

📝 TODO: Needs source — specific indications, dosing protocols, evidence base for morbid jealousy.

Dosage

📝 TODO: Needs source — starting dose, titration schedule, maximum dose.

Side Effects

• Gastrointestinal — nausea, diarrhoea (common at initiation).
• Sexual dysfunction — delayed ejaculation, anorgasmia (common with all SSRIs).
• Insomnia and agitation.
• Serotonin syndrome — rare but serious; occurs with concurrent use of other serotonergic drugs.
• Weight changes — generally weight-neutral compared to other antidepressants.

📝 TODO: Needs source — specific side effect incidence, discontinuation syndrome.

Contraindications

📝 TODO: Needs source — concurrent monoamine oxidase inhibitor (MAOI) use, mania.

Drug Interactions

📝 TODO: Needs source — interactions with other serotonergic drugs (risk of serotonin syndrome), monoamine oxidase inhibitors (MAOIs), warfarin, antiplatelet agents.

Sri Lanka Availability

📝 TODO: Needs source — availability in Sri Lankan government hospitals.

Exam Focus

Viva Questions

• When is fluoxetine used in morbid jealousy? (For the obsessive type, where the patient has insight — as opposed to the delusional type treated with antipsychotics.)
• What class of drug is fluoxetine? (Selective serotonin reuptake inhibitor [SSRI].)

MCQ Traps

• ⚠️ EXAM DETAIL: Treatment choice in morbid-jealousy depends on the psychopathological type — antipsychotics for delusional, fluoxetine/clomipramine for obsessive.
• ⚠️ EXAM DETAIL: Fluoxetine has a long half-life (several days) compared to other SSRIs, which means a longer washout period is needed before switching to a monoamine oxidase inhibitor (MAOI).

Source Notes

• Information in this page is drawn from the management discussion in morbid-jealousy, which is sourced from the Handbook of Clinical Psychiatry (de Silva & Hanwella).