Fluoxetine
Antidepressant — SSRI
Indications
DepressionOCDBulimia nervosa
Adult dose
Depression: 20 mg OD, max 60 mg. OCD/bulimia: up to 60 mg OD.
Paediatric dose
Depression (8–17 yrs): 10 mg OD, increase after 1–2 weeks to 20 mg OD if needed. Only SSRI licensed for paediatric depression in UK.
Common side effects
NauseaInsomniaAnxiety/agitation earlyAnorexiaSexual dysfunction
Serious side effects
Serotonin syndromeHyponatraemiaSuicidality (<25 yrs early)
Contraindications
MAOI within 14 days (and ≥5 weeks after stopping fluoxetine before MAOI)
Monitoring
- Mood/suicidality early; weight in eating disorders
Notable interactions
- Strong CYP2D6 inhibitor — raises levels of TCAs, antipsychotics, opioids (codeine reduced efficacy), tamoxifen (avoid)
- MAOIs
Notes
Long half-life (norfluoxetine ~4–16 days) — useful for non-adherent patients but complicates switching.
Curated reference based on BNF, Maudsley Prescribing Guidelines and NICE. Verify against current BNF and local guidelines before prescribing.