Fluoxetine at a glance
Medicine class
Selective serotonin reuptake inhibitor (SSRI) antidepressant.
Available forms
Capsules, tablets, dispersible tablets and oral solution are available.
Food
It can be taken with or without food.
What is Fluoxetine used for?
Selected UK products are licensed for:
Major depressive episodes in adults.
Obsessive-compulsive disorder in adults.
Bulimia nervosa in adults, alongside psychotherapy to reduce binge eating and purging.
Moderate-to-severe major depression from age 8 when psychological therapy alone has not worked; treatment must be combined with psychological therapy and specialist-supervised.
How does Fluoxetine work?
Fluoxetine reduces serotonin reuptake into nerve cells, increasing serotonin signalling. The full relationship between this effect and clinical improvement is not completely understood.
Fluoxetine preparations and strengths
Capsule
Route: Oral
Strengths: 10 mg, 20 mg, 30 mg, 40 mg, 60 mg
How to take Fluoxetine
Follow the dispensing label and product instructions. Do not stop fluoxetine suddenly without discussing it with the prescriber.
Swallow tablets or capsules with water, with or without food.
Olena dispersible tablets can be swallowed with water or dispersed in half a glass of water immediately before taking. Do not crush or chew them.
Measure oral solution with the supplied oral syringe or medicine spoon, not a household teaspoon.
Do not drive, cycle or operate machinery if fluoxetine causes dizziness, drowsiness or blurred vision.
Fluoxetine side effects
Common or expected effects
- Headache
- Nausea, vomiting or diarrhoea
- Difficulty sleeping
- Tiredness or weakness
- Dizziness or drowsiness
- Reduced appetite or weight change
- Anxiety, restlessness or tremor
- Sexual problems
- Dry mouth or increased sweating
Get urgent medical advice
- Suicidal thoughts or marked mood worsening
- Serotonin syndrome
- Severe allergic reaction
- Blistering or peeling skin
- Seizures
- Mania or hypomania
- Unexplained bleeding, black stools or extensive bruising
- Fainting, collapse or a fast or irregular heartbeat
- Severe confusion, weakness or drowsiness that may indicate low blood sodium
- A prolonged or painful erection
Fluoxetine in pregnancy
Fluoxetine can be used during pregnancy when expected benefit justifies possible risks. Evidence suggests a small possible increase in some cardiac defects. Late-pregnancy exposure can occasionally cause temporary newborn adaptation symptoms and is associated with uncommon risks including persistent pulmonary hypertension or postpartum bleeding. Do not stop abruptly; discuss pregnancy or plans to conceive with the prescriber.
Fluoxetine while breastfeeding
Fluoxetine and its active metabolite enter breast milk and may accumulate. It can be used cautiously after individual assessment, although sertraline or paroxetine are generally preferred when starting treatment. Monitor the infant for irritability, unusual sleepiness, restlessness, colic, feeding problems and appropriate weight gain.
Fluoxetine interactions
Check all prescribed, pharmacy and herbal products with a pharmacist or prescriber because interactions can persist after fluoxetine is stopped.
Irreversible non-selective monoamine oxidase inhibitors (MAOIs)
Contraindicated because the combination can cause severe or fatal serotonin syndrome.
Metoprolol used for heart failure
Contraindicated because fluoxetine can increase metoprolol exposure and cause excessive slowing of the heart.
Tamoxifen
Fluoxetine may reduce formation of tamoxifen's active metabolite and should be avoided where possible.
Common questions about Fluoxetine
Answers are fully visible for fast scanning and source review.
Can fluoxetine affect driving?
It can cause dizziness, drowsiness, blurred vision or impaired judgement. Do not drive, cycle or operate machinery until you know you are unaffected.
Is fluoxetine addictive?
Fluoxetine is not considered addictive, but stopping suddenly can cause withdrawal symptoms and allow the treated condition to return.
Can fluoxetine cause sexual problems?
Yes. Reduced libido and problems with erection, ejaculation or orgasm can occur. Persistent sexual dysfunction after stopping has also been reported.
Can children and teenagers take fluoxetine?
Selected UK products are licensed from age 8 for moderate-to-severe major depression when psychological therapy alone has not worked. Treatment must be specialist-supervised and combined with psychological therapy.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.