Fluoxetine
A long-established antidepressant. Its very long half-life means fewer withdrawal symptoms but slow wash-out. Sometimes used in young people, with specialist guidance.
Brand names
- Prozac, Lovan, Zactin, plus generic brands sold as fluoxetine
How it works
A selective serotonin reuptake inhibitor (SSRI) that increases serotonin between nerve cells. It and its active breakdown product last for weeks (half-lives about 4 to 16 days), so effects build and fade slowly.
Used for
- Major depression (TGA-approved)
- Obsessive-compulsive disorder (TGA-approved)
- Premenstrual dysphoric disorder, severe premenstrual mood symptoms (TGA-approved)
- Depression in children and teens aged 8 and over, with talking therapy and specialist guidance
Side effects
How often, from the official product information. Bold = serious.
Very common more than 1 in 10
- Poor sleep
- Headache
- Diarrhoea or nausea
- Tiredness
Common 1 in 10 to 1 in 100
- Less appetite, weight loss
- Anxiety, restlessness, odd dreams
- Poor focus, dizziness, tremor
- Blurred vision, palpitations, long QT
- Flushing, sweating, rash, itch
- Vomiting, indigestion, dry mouth
- Joint pain, passing urine more
- Sexual problems, vaginal bleeding
- Jittery, chills
Uncommon 1 in 100 to 1 in 1,000
- Suicidal thoughts, high mood
- Teeth grinding, twitching, poor balance
- Large pupils, ringing ears, low BP
- Nosebleeds, gut bleeding, bruising
- Hair loss, breathlessness
Rare 1 in 1,000 to 1 in 10,000
- Low blood counts, low sodium
- Anaphylaxis, angioedema
- Mania, hallucinations, aggression
- Seizures, serotonin syndrome
- Dangerous heart rhythms, hepatitis
- Severe skin reactions
- Urine retention, prolonged erection
Frequency not known reported, rate unclear
- Heavy bleeding after birth
Get help urgently if
- Fever, sweating, shaking, muscle jerks, confusion or a racing heart (possible serotonin syndrome)
- Thoughts of suicide or self-harm: Lifeline 13 11 14, or 000
- Black or bloody stools, or vomiting blood
- Face or throat swelling, trouble breathing, or a seizure
Good to know
- Young people: growth is checked. Under 25s: suicidal thoughts can increase early on. Thoughts of self-harm: see your doctor now or call Lifeline 13 11 14.
- Serotonin syndrome is more likely with tramadol, triptans, St John’s wort or other antidepressants. Never use with an MAOI.
- Bleeding is more likely with anti-inflammatories (NSAIDs), aspirin or blood thinners.
- Low sodium (confusion, unsteadiness) is more likely in older people.
- Stopping: withdrawal is less likely (long half-life). Wait 5 weeks before an MAOI. Interacts with tamoxifen.
- Sexual side effects are common. Pregnancy or breastfeeding: discuss with your doctor. Avoid alcohol.
Information only. Not a recommendation or endorsement of any product. Whether a medicine suits you depends on your health and other medicines, so talk to your doctor or pharmacist. In an emergency, call 000.
More information
maladywise.com/drugs/fluoxetine/