Fluoxetine

  • It may take a week or two after starting this treatment before you feel the benefit. Do not stop taking fluoxetine, thinking it is not helping.
  • Tell your doctor if you feel that you are getting worse or if you experience any troublesome side-effects.
  • Fluoxetine may slow your reactions. Make sure your reactions are normal before driving.
Type of medicine Selective serotonin re-uptake inhibitor (SSRI) antidepressant
Used for Depression
Bulimia nervosa
Obsessive-compulsive disorder
Also called Oxactin®
Prozac®
Prozep®
Available as Capsules and oral liquid

Anyone can develop depression. It can develop for no apparent reason or it may be triggered by a life event such as a relationship problem, bereavement, or illness.

Brain cells called neurons, release a number of chemicals which go on to stimulate other neurons leading to electrical impulses which result in many functions controlled by the brain. Serotonin is one such chemical in the brain. Once released, it stimulates other neurons and is then taken back up into the neuron cells and recycled. Antidepressants like fluoxetine increase the amount of circulating serotonin available in the brain. This may help depression symptoms in some people.

Although fluoxetine is often used to treat depression, it can also reduce the symptoms of obsessive-compulsive disorder (OCD) and help in the treatment of bulimia nervosa.

Before taking fluoxetine make sure your doctor or pharmacist knows:

  • If you are under 18 years of age.
  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have heart or liver problems.
  • If you have epilepsy.
  • If you have diabetes.
  • If you have glaucoma (increased pressure in your eye).
  • If you have a bleeding disorder.
  • If you have ever had abnormally 'high' moods.
  • If you are being treated with electroconvulsive therapy (ECT).
  • If you have ever had an allergic reaction to this or to any other medicine.
  • If you have taken an antidepressant known as a monoamine-oxidase inhibitor (MAOI) within the previous two weeks.
  • If you are taking any other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take fluoxetine exactly as your doctor has told you.
  • Try to take fluoxetine at the same times each day to avoid missing any of your doses.
  • It is not important whether you take fluoxetine before, during or after food.
  • If you do forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • You may feel that fluoxetine is not working for you straightaway. It can take a week or two after starting this treatment before the effect builds up and 4-6 weeks before you feel the full benefit. Do not stop taking it after a week or so, thinking it is not helping.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • You are advised not to drink alcohol while you are being treated with fluoxetine. Taking fluoxetine and alcohol may increase the chance that you experience side-effects.
  • If you have diabetes you may need to check your blood glucose more frequently, as fluoxetine may affect the levels of sugar in your blood. Your doctor will be able to advise you about this.
  • Fluoxetine may cause your skin to become more sensitive to sunlight than usual. Avoid strong sunlight and sunbeds until you know how your skin reacts.
  • If you buy any medicines, check with a pharmacist that they are safe to take with fluoxetine.
  • There are several types of antidepressants and they differ in their possible side-effects. If you find that fluoxetine does not suit you then let your doctor know, as another may be found that will.
  • Do not stop taking fluoxetine unless your doctor tells you to do so. Stopping treatment suddenly can cause problems and your doctor will probably want you to reduce your dose gradually if this is necessary.
  • While you feel depressed or are taking fluoxetine, you may have thoughts about harming yourself or ending your life. It is very important that you tell your doctor about this if it happens.
  • If you are taking fluoxetine for depression, you should expect that a normal course of treatment will last for around six months after your symptoms have eased.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common fluoxetine side-effects What can I do if I experience this?
Feeling or being sick, indigestion, abdominal pain, diarrhoea Stick to simple foods and drink plenty of water
Constipation Try to eat a well-balanced diet containing plenty of fibre and drink 6-8 glasses of water each day
Dry mouth Try chewing sugar-free gum or sweets
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
Sleepiness, dizziness, weakness If this happens, do not drive or use tools or machines. If the dizziness happens when you stand up, try getting up more slowly and wait for a few moments so that you do not feel faint. Let your doctor know if this continues
Increased sweating, difficulty sleeping, restlessness, hair loss, anxiety, lack of appetite, loss of weight, muscle and joint pains, passing urine more frequently or difficulties passing urine, feeling shaky, sexual difficulties, breast changes, yawning, sore throat, changes in taste, poor concentration If any of these become troublesome, speak with your doctor

Important: if you develop any of the following, contact your doctor straightaway or go to the accident and emergency department of your local hospital:

  • Any swelling of the mouth or face.
  • Any shortness of breath or difficulty swallowing.
  • An itchy rash.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never take more than the prescribed dose. If you suspect that someone has taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.
  • Never keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Helen Huins
Last Checked:
15/12/2011
Document ID:
3418 (v23)
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The Information Standard - certified member