What fluoxetine is for
Fluoxetine can be used to treat mental health conditions such as:
- depression
- obsessive compulsive disorder (OCD)
- bulimia
It can sometimes be used for menopause symptoms.
Fluoxetine is a type of antidepressant called a selective serotonin reuptake inhibitor (SSRI).
It’s thought to work by increasing the level of serotonin (a chemical in the brain linked to mood). When serotonin levels are normal, this may reduce stress levels and negative thoughts.
How to take fluoxetine
Fluoxetine comes as tablets, capsules or liquid that you swallow. Some tablets can be dissolved in water (dispersible).
You usually take fluoxetine once a day. How much you need to take depends on why you’re taking it.
Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you’re not sure how to take it or have any problems taking it.
Depending on why you’re taking fluoxetine, your doctor may prescribe a lower dose to start with and then increase it after 3 or 4 weeks. It can take a few weeks before your symptoms start to improve.
When taking fluoxetine:
- swallow tablets or capsules whole, with a glass of water
- if you have dispersible tablets, you can either swallow them whole with half a glass of water, or let them dissolve in half a glass of water which you then drink
- use the syringe or spoon that comes with the liquid medicine to help you measure the right dose
- take it at the same time each day
- you can take it with or without food
You may need to take fluoxetine for a long time. For example, if you’re taking it for depression, you’ll probably need to keep taking it for several months, or longer.
If you miss a dose of fluoxetine
If you forget to take fluoxetine, take it as soon as you remember, unless it’s nearly time for your next dose.
If it’s nearly time for your next dose, skip the missed dose and take your next dose at the usual time
Do not take 2 doses to make up for a missed dose.
If you take too much fluoxetine
Taking an extra dose of fluoxetine can be dangerous.
Urgent advice: Get help from NHS 111 if:
- you’ve taken more than your prescribed dose of fluoxetine
You can call 111 or get help from 111 online.
If you’re told to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the fluoxetine packet or leaflet inside it, any remaining medicine, and any other medicines you take.
How to stop taking fluoxetine
Your doctor may suggest you stop taking fluoxetine if you’ve been feeling better for some time.
But do not suddenly stop taking it because it may cause withdrawal symptoms. If you want to stop taking fluoxetine, speak to your doctor first.
They doctor will gradually reduce your dose over several weeks or months. Always follow your doctor’s advice.
Side effects of fluoxetine
Like all medicines, fluoxetine can cause side effects, although not everyone gets them.
Some side effects should ease after a couple of weeks as your body gets used to the medicine, but some can last longer.
Common side effects
Common side effects of fluoxetine include:
- headaches
- feeling sick (nausea) and being sick (vomiting)
- diarrhoea or constipation
- weight changes
- sexual problems, such as low sex drive (loss of libido)
- problems sleeping
- feeling dizzy or drowsy (sleepy)
- blurred vision
If you feel dizzy, drowsy or have blurred vision after taking fluoxetine, do not drive, ride a bike or use machinery these symptoms have gone away.
Non-urgent advice: Speak to a pharmacist or doctor if:
Serious side effects
Fluoxetine can sometimes cause more serious side effects, although most of them are rare.
Possible serious side effects of fluoxetine include:
- serotonin syndrome – a condition that causes a fast heartbeat, sweating, shaking, twitching muscles and feeling confused or agitated
- very low mood and having suicidal thoughts
- high moods (mania or hypomania) – for example feeling very happy, excited or energetic
- unexplained bruising or bleeding, or blood in your poo (poo may look red or black)
- an allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised, itchy rash and difficulty breathing
Urgent advice: Call NHS 111 if:
- you’re taking fluoxetine and think you might be having serious side effects
- you’re having thoughts about harming yourself
More about side effects
These are not all the side effects of fluoxetine.
For a full list, see the leaflet inside your medicines packet, or search for your medicine leaflet on the electronic medicines compendium website.
You can report any side effects you get on the Yellow Card Scheme website
Who can and cannot take fluoxetine
Most adults can take fluoxetine.
It’s also sometimes used to treat depression in children aged 5 years or older.
Fluoxetine is not suitable for everyone. For example, it may not be suitable if:
- you’ve had an allergic reaction or serious side effect from fluoxetine or another selective reuptake inhibitor (SSRI) antidepressant
- you have diabetes
- you have epilepsy
- you have heart disease
- you have glaucoma
- you have a bleeding disorder (particularly bleeding in the digestive system)
- you’ve ever had mania (high moods caused by a mental health condition)
Before taking fluoxetine, tell your doctor if you have any other medical conditions.
Breastfeeding and fluoxetine
Tell your doctor if you’re breastfeeding.
Fluoxetine is sometimes used while breastfeeding, but it’s best to check because the medicine can pass into your breast milk.
You may be able to take it if the benefits outweigh the risks. Sometimes your doctor might want to switch you to a different antidepressant, such as sertraline.
It’s possible for breastfed babies to get side effects from fluoxetine, so speak to a healthcare professional or call NHS 111 if you have any concerns about your baby.
Pregnancy and fluoxetine
Tell your doctor if you’re pregnant or you get pregnant while taking fluoxetine.
Fluoxetine can be used during pregnancy if needed. Your doctor will talk to you about the risks and benefits of taking it while you’re pregnant.
If you need to take fluoxetine while you’re pregnant, your doctor will prescribe the lowest possible effective dose.
You’ll also usually be advised to give birth in hospital so you and your baby can be closely monitored after you’ve given birth.
Taking fluoxetine with other medicines, food and drink
There are some medicines, remedies and supplements that may not mix well with fluoxetine.
These include:
- antidepressants called monoamine oxidase inhibitors (MAOIs), such as moclobemide and selegiline
- metoprolol, a medicine for heart failure
- tamoxifen, a medicine for breast cancer
- anticoagulants, such as warfarin and apixaban
- NSAIDs, such as aspirin and ibuprofen
- diuretics, medicines for high blood pressure and swelling (oedema)
- buprenorphine, an opioid painkiller
Do not use the herbal supplement St John’s wort when taking fluoxetine.
Before taking fluoxetine, tell your doctor if you’re taking any other medicines, herbal remedies, vitamins or supplements.
Food, drink and alcohol with fluoxetine
You can eat and drink normally when taking fluoxetine.
It’s best to not to drink alcohol while taking fluoxetine because it can increase the risk of side effects, such as feeling very sleepy (drowsy).
Find out more about your medicine
To find out more about your medicine, you can: