Fluoxetine
Generic name: fluoxetine hydrochloride · Brand name: Prozac®
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How It Works
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) and one of the longest-studied antidepressants available. It works by blocking serotonin reabsorption in the brain, increasing serotonin availability between nerve cells. Fluoxetine has the longest half-life of any SSRI — meaning it stays in your system longer — which makes it more forgiving if a dose is missed and causes fewer withdrawal effects if stopped.
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What It Treats
Major Depressive Disorder (MDD)Persistent low mood, fatigue, loss of interest, sleep and appetite changes
Obsessive-Compulsive Disorder (OCD)Unwanted intrusive thoughts and repetitive behaviors
Panic DisorderRecurrent unexpected panic attacks and anticipatory anxiety
Bulimia NervosaFDA-approved for reducing binge-eating and purging episodes
Bipolar DepressionUsed in combination with olanzapine (as Symbyax)
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Dosing Overview
| Population | Start | Typical Range | Max |
|---|---|---|---|
| Adults Depression / Anxiety | 10–20 mg | 20–40 mg | 80 mg |
| Adults OCD | 20 mg | 40–60 mg | 80 mg |
| Adults Bulimia | 20 mg | 60 mg | 80 mg |
| Children (8+) Depression / OCD | 10 mg | 20–30 mg | 60 mg |
Taken once daily, usually in the morning (can cause insomnia if taken at night). Long half-life means missing a dose rarely causes problems. Doses adjusted every 4–6 weeks.
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What to Expect — Timeline
1–2
Weeks 1–2
Body adjusting. May notice sleep changes, mild nausea, or fatigue before mood lifts
3–4
Weeks 3–4
Many notice improved sleep, energy, or motivation. Anxiety may still feel elevated
6–8
Weeks 6–8
Mood and anxiety typically improve significantly at a therapeutic dose
3–6m
3–6 Months
Full therapeutic benefit. Duration discussed based on your history and goals
⏳ Be patient. Most people need at least 4–8 weeks at a therapeutic dose before evaluating effectiveness. Do not stop without talking to your provider.
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Side Effects
Common (often temporary)
- Nausea or upset stomach
- Headache
- Insomnia or vivid dreams
- Dry mouth
- Increased sweating
- Decreased appetite / weight loss
- Sexual side effects
- Nervousness or jitteriness
Call us if you notice
- Worsening depression or anxiety
- New or increased suicidal thoughts
- Agitation or restlessness
- Unusual bleeding
- Hypomania or mania-like symptoms
- Serotonin syndrome signs (fever, confusion, tremor)
Most side effects are mild and improve within 1–2 weeks. Fluoxetine is more activating than other SSRIs — if jitteriness or insomnia occurs, taking it in the morning helps. Weight loss is more common with fluoxetine than other SSRIs.
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Tips for Success
Same Time DailyTake at the same time each day for consistent levels in your system.
With FoodTaking with food can reduce nausea, especially in the first weeks.
Don't Stop AbruptlyStopping suddenly can cause dizziness and mood changes. Always taper with guidance.
Limit AlcoholAlcohol worsens depression and anxiety and may increase side effects.
Tell All ProvidersLet other prescribers know you take this medication — interactions matter.
Track Your MoodJournaling or a mood app helps you and your provider see what is changing.
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Important Safety Information
Black Box Warning (under 25): Antidepressants may increase risk of suicidal thinking in children, adolescents, and young adults, especially in the first few weeks. Monitor closely and contact us right away if new or worsening thoughts of self-harm appear.
Serotonin Syndrome: A rare but serious reaction when combined with MAOIs, triptans, tramadol, or St. John's Wort. Signs include fever, agitation, rapid heart rate, muscle twitching, or confusion — seek emergency care immediately.
Drug Interactions: Do not take with MAOIs (must wait 14 days between). Use caution with blood thinners and NSAIDs. Always share your full medication list with your provider.
Pregnancy & Breastfeeding: Discuss risks and benefits with your provider. Do not stop without consultation.
Questions? I'm here.
Reach me between appointments if you have concerns about side effects, notice mood changes, or have questions about your medication. You don't have to wait until your next visit.
360-389-3712
info@rootedmindspsychiatry.com