What it is used for

Depression, including in children and young people aged 8 and over
Obsessive compulsive disorder (OCD)
Bulimia nervosa

Read our guides:

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

Panic disorder and other anxiety conditions
Premenstrual dysphoric disorder (severe PMS)

How it works

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). It increases serotonin in the brain, which helps regulate mood, anxiety and eating behaviour. It can take 4 to 6 weeks to work.

Side effects

Like all medicines, Fluoxetine can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

feeling sick
headache
trouble sleeping
feeling anxious or restless
diarrhoea
loss of appetite
sexual problems

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

thoughts of harming yourself or ending your life
unusual bleeding or bruising
a fast or irregular heartbeat
signs of serotonin syndrome, such as confusion, high temperature and muscle twitching

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

Tell your doctor straight away if you feel worse or have thoughts of suicide, especially if you are under 25.
It interacts with many medicines because it stays in the body for weeks.
Do not take it with St John's wort.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.