Prozac (fluoxetine)

How does it work?

Prozac capsules and liquid contain the active ingredient fluoxetine, which is a type of antidepressant known as a selective serotonin reuptake inhibitor (SSRI). (NB. Fluoxetine is also available without a brand name, ie as the generic medicine.)

Antidepressant medicines act on nerve cells in the brain. In the brain there are numerous different chemical compounds called neurotransmitters. These act as chemical messengers between the nerve cells. Serotonin is one such neurotransmitter and has various functions that we know of.

When serotonin is released from nerve cells in the brain it acts to lighten mood. When it is reabsorbed into the nerve cells, it no longer has an effect on mood. It is thought that when depression occurs, there may be a decreased amount of serotonin released from nerve cells in the brain.

SSRIs work by preventing serotonin from being reabsorbed back into the nerve cells in the brain. This helps prolong the mood lightening effect of any released serotonin. In this way, fluoxetine helps relieve depression.

Fluoxetine may also be used in the treatment of bulimia nervosa and obsessive compulsive disorder in adults. It is not fully understood how fluoxetine works in these illnesses.

It may take between two to four weeks for the benefits of this medicine to appear, so it is very important that you keep taking it, even if it doesn't seem to make much difference at first. If you feel your depression has got worse, or if you have any distressing thoughts or feelings in these first few weeks, then you should talk to your doctor.

What is it used for?

In adults fluoxetine is used to treat:

depressive illness

a psychiatric disorder in which tasks are excessively repeated (obsessive-compulsive disorder)

bulimia nervosa.

In children and adolescents aged eight years and over fluoxetine is used to treat:

moderate to severe major depressive episodes, if the depression is unresponsive to psychological therapy after four to six sessions. (Fluoxetine should only be prescribed by a specialist and should be used in combination with psychological therapy.)

Warning!

Depression and other psychiatric illnesses are associated with an increased risk of suicidal thoughts, self-harm, and suicide. You should be aware that this medicine may not start to make you feel better for at least two to four weeks. However, it is important that you keep taking it in order for it to work properly and for you to feel better. If you feel your depression or anxiety has got worse, or if you have any distressing thoughts, or feelings about suicide or harming yourself in these first few weeks, or indeed at any point during treatment or after stopping treatment, then it is very important to talk to your doctor.

In children, fluoxetine is not licensed or recommended for uses other than moderate to severe depression. Children and adolescents may be more susceptible to hostility and suicidal thoughts or behaviour when starting treatment with antidepressants. They should be carefully monitored and encouraged to report any distressing feelings, thoughts about suicide or self-harm, irritability, mood changes or other unusual change in behaviour that they may experience while taking the medicine. If you are worried about your child at any point it is important to talk to your doctor immediately.

There is only limited evidence available concerning the long-term safety of fluoxetine in children and adolescents, in terms of its effect on growth (height and weight) and sexual, cognitive, emotional and behavioural development. Your doctor should carefully discuss the risks and benefits of the medicine with you and your child before treatment is started. The child's growth and development should be monitored during and after treatment. If there is no obvious benefit on the child's depression after nine weeks of treatment, use of the medicine should be reconsidered.

This medicine may reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.

It is recommended that you avoid drinking alcohol while taking this medicine.

SSRI antidepressants have been associated with the development of unpleasant or distressing restlessness and the need to move, often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. If you experience these symptoms you should consult your doctor.

Antidepressants may cause the amount of sodium in the blood to drop - a condition called hyponatraemia. This can cause symptoms such as drowsiness, confusion, muscle twitching or convulsions. Elderly people may be particularly susceptible to this effect. You should consult your doctor if you develop any of these symptoms while taking this medicine, so that your blood sodium level can be checked if necessary.

You should avoid suddenly stopping this medicine, as suddenly stopping SSRIs can cause symptoms such as headache, nausea, pins and needles, dizziness and anxiety. Withdrawal symptoms are temporary and are not due to addiction or dependence on the medicine. They are rare with fluoxetine, because it remains in your blood for a few weeks after you stop taking it, and its blood level naturally decreases slowly over time. However, you should follow the instructions given by your doctor or pharmacist when it is time to stop treatment.

If you experience seizures (convulsions or fits) while taking this medicine, consult your doctor immediately, as you will need to stop treatment with this medicine. This also applies if you suffer from epilepsy and experience more seizures than normal after starting this medicine.

Consult your doctor if you develop a skin rash or other unexplained allergic reaction while taking this medicine.

Use with caution in

Elderly people.

Children and adolescents.

Young adults.

History of suicidal behaviour or thoughts.

History of mania, hypomania or manic depression.

People also receiving electroconvulsive therapy (ECT).

People taking antipsychotic medicines.

Decreased liver function.

Heart disease.

Diabetes.

Epilepsy.

History of seizures.

History of bleeding disorders.

People taking medicines that affect blood clotting (eg anticoagulants such as warfarin - see end of factsheet for more information).

Not to be used in

People who have taken a monoamine-oxidase inhibitor antidepressant (MAOI) in the last 14 days.

Manic episodes.

Uncontrolled epilepsy.

Uncontrolled seizure disorders, eg due to brain injury.

Prozac liquid contains sucrose and should not be used by people with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

This medicine can be used during pregnancy, but only with caution and if the benefits to the mother outweigh any risk to the foetus. This is particularly important in the third trimester and prior to and during labour, as the medicine may cause fluoxetine-type side effects or withdrawal symptoms in the newborn baby. Seek medical advice from your doctor if you get pregnant or plan to have a baby while taking this medicine.

This medicine passes into breast milk and may have adverse effects on a nursing infant. Mothers who need to take this medicine should discuss the risks and benefits of breastfeeding with their doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Headache.

Dry mouth.

Difficulty in sleeping (insomnia).

Fatigue.

Sweating.

Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.

Visual disturbances.

Dizziness.

Seizures.

Hair loss (alopecia).

Sexual problems.

Decreased appetite and weight loss.

Anxiety and agitation.

Small purplish blood spots in the skin (ecchymoses).

Pain in the muscles and joints.

Allergic reactions such as itchy, blistering skin rash (urticaria) or swelling of the lips, tongue and throat (angioedema).

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

Go To Next Page>>
The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care or attention by a qualified practitioner. The materials in this web site cannot and should not be used as a basis for diagnosis or choice of treatment. Conditions for use



© Copyright 1998 - 2004 NetDoctor.co.uk - All rights reserved