Fluoxetine
Brand names: Prozac
Class: 🧠 SSRIs & SNRIs
For the FNP boards, fluoxetine is the SSRI with the longest half-life — and that property is the exam point. The active metabolite norfluoxetine has a half-life of about a week, so fluoxetine self-tapers and rarely causes discontinuation syndrome. Indications include major depression in adults and pediatrics (FDA-approved down to age 8), OCD, bulimia, panic disorder, and PMDD. The trade-off is a longer washout before starting an MAOI (5 weeks) and more drug interactions through CYP2D6 and CYP3A4 inhibition. It is more activating than other SSRIs — useful in atypical depression with hypersomnia, problematic with insomnia. Pair with caution alongside tramadol, triptans, or linezolid (serotonin syndrome).
✅ Indications
MDD (adults + peds), OCD, bulimia, panic, PMDD.
⚙️ Mechanism of Action
SSRI — very long half-life (~4–6 days + active metabolite).
📏 Dosing
10–20 mg PO daily; bulimia 60 mg daily.
🚫 Contraindications
MAOI within 14 days (use 5 weeks washout after fluoxetine due to long t½), pimozide, thioridazine.
⚠️ Adverse Effects
Anxiety/agitation early, insomnia, sexual dysfunction, nausea; less discontinuation syndrome (long t½).
🔬 Monitoring
Mood, suicide screen.
💎 Board Pearls
- ⏳ LONGEST half-life (active metabolite norfluoxetine ≈ 7–15 days) — no taper needed.
- 👶 ONLY SSRI FDA-approved for pediatric depression (plus escitalopram).
- 🚫 5-week MAOI washout after stopping (vs 2 weeks for other SSRIs).
Practice Questions
Which of the following SSRIs is FDA-approved for the treatment of pediatric major depressive disorder in children as young as 8 years of age?
Related Drugs in This Class
- Sertraline — Zoloft
- Escitalopram — Lexapro
- Venlafaxine — Effexor XR
Sources
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