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Antidepressants

Published by Bupa's health information team, March 2009.

This factsheet is for people who are taking antidepressants, or who would like information about them.

Antidepressants are used to treat depression. This factsheet provides information on the two most commonly prescribed groups of antidepressants - tricyclic antidepressants (tricyclics) and selective serotonin re-uptake inhibitors (SSRIs).

Why would I take antidepressants?

Your GP may prescribe antidepressants if you have depression. This is a condition in which you may have low mood, a loss of interest in everyday activities, feelings of low self-worth, a lack of energy and poor concentration, all of which are prolonged. You're said to have depression when your feelings:

Depression may be classed as mild, moderate or severe. This depends on how many symptoms you have and how badly they interfere with everyday life, rather than how you feel. Antidepressants are often not needed for mild depression. Psychological therapies, or talking treatments, such as counselling or cognitive behavioural therapy, may be better for this type of depression.

Antidepressants may also be prescribed to help treat other conditions such as bedwetting in children and chronic pain or anxiety in adults.

What are the main types of antidepressant?

The main types of antidepressant are tricyclics and SSRIs. Both work well for moderate or severe depression but have different side-effects. Your GP will usually prescribe the one that will cause you the fewest problems.

How do antidepressants work?

Doctors and scientists don't fully understand what happens in the brain during mood problems such as depression. Nor do they know exactly how the treatments that are effective actually work. But it's known that people who are depressed usually have reduced levels of certain brain chemicals called neurotransmitters, such as noradrenaline and serotonin. Medicines that increase levels of noradrenaline and serotonin work as treatments for depression.

Neurotransmitters are released by nerve cells. They carry a burst of information across the tiny gap between the nerve cell and its neighbour. This is how information is transmitted from one nerve cell to the next. Once they have done their job, neurotransmitters are re-absorbed into the nerve cell - this is called re-uptake. Medicines that increase levels of neurotransmitters work by either encouraging cells to make more of them, or by preventing their re-uptake. In both cases, there are more neurotransmitters in the gap between cells, so information can travel more effectively.

Tricyclics increase levels of both noradrenaline and serotonin while SSRIs increase levels of serotonin only.

How to take antidepressants

Tricyclics and SSRIs are only available on a doctor's prescription. They come as tablets or capsules and sometimes in a liquid form. Antidepressants usually take two to four weeks before they start having an effect. Many of the side-effects caused by these medicines occur immediately, but may reduce with time.

You will probably need to carry on taking an antidepressant that works for you for at least four to six months, even once your symptoms have gone away. Continuing medication after you feel better can help prevent your depression coming back.

You may need to take antidepressants continuously if you get repeated bouts of depression.

Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Special care

If you have heart problems or reduced liver function, or if you're pregnant or breastfeeding, tell your GP before taking any antidepressant.

At the same time as a course of antidepressants, you may also be offered some psychological treatment, such as counselling or cognitive behavioural therapy, which may work better than antidepressants on their own.

Side-effects of antidepressants

Common side-effects with tricyclics are:

Some of these side-effects settle down with time, so you should persevere with treatment if you get these symptoms.

Tricyclics may cause arrhythmia (heart palpitations) and fits. An overdose of tricyclics can be dangerous for your heart.

The SSRIs also have side-effects but they may be less troublesome. In particular, they don't cause drowsiness. Other possible side-effects include:

Less commonly, SSRIs can cause:

SSRIs, except for fluoxetine, aren't recommended for people under 18, because of concerns that they may increase the risk of self-harm in this age group.

If you're worried about side-effects that may be caused by antidepressants, ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Antidepressants aren't addictive but you may get withdrawal symptoms if you stop taking them suddenly. Symptoms of sudden withdrawal include feeling sick, vomiting, loss of appetite, headaches, dizziness, chills, insomnia, anxiety and panic. If you want to stop taking antidepressants, talk to your GP first. He or she may suggest that you reduce the dose slowly, as this can prevent withdrawal symptoms.

Taking certain antidepressants can affect some activities such as driving. Don't carry out such tasks until you know how you react to your medicine.

Interactions of antidepressants with other medicines

Check with your doctor or pharmacist before you take any other medicines or herbal remedies at the same time as your antidepressants. St John's wort, which is sold as a herbal antidepressant, can be harmful when taken with prescribed antidepressants.

Names of common antidepressants

Examples of the main types of antidepressants are shown in the table.

You may have noticed that your medicine has two or more names. Every medicine has a generic name, which is its official medical name. Many medicines also have at least one brand name, which is the trade name. Generic names are written in lower case and brand names start with a capital letter.

There are many different medicines for depression. Some have more than one ingredient, or different ingredients sold under the same brand name. If you're not sure about the tablets you have been prescribed, ask your pharmacist for advice.

Generic name Brand name

Tricyclic antidepressants

amitriptyline

Elavil

clomipramine

Anafranil

dothiepin/dosulepin

Prothiaden

doxepin

Sinequan

imipramine

Tofranil

lofepramine

Gamanil

nortriptyline

Allegron

trimipramine

Surmontil

Selective serotonin re-uptake inhibitors (SSRIs)

citalopram

Cipramil

escitalopram

Cipralex

fluoxetine

Prozac

fluvoxamine

Faverin

paroxetine

Seroxat

sertraline

Lustral

Other antidepressants

Alternatives to tricyclics and SSRIs include venlafaxine (Efexor), reboxetine (Edronax) and mirtazapine (Zispin). These also work by affecting the levels of neurotransmitters in your brain and may work better for specific symptoms. They may also be an option if a tricyclic or SSRI hasn't worked for you.

Another group of antidepressants known as monoamine oxidase inhibitors (MAOIs) is also available. Medicines in this group include phenelzine (Nardil) and moclobemide (Manerix). MAOIs can have lots of interactions with other medicines and foods such as cheese, increasing the risk of side-effects. They aren't commonly prescribed, but may be worth trying if other types of antidepressant haven't worked for you.

Further information

Related topics

Sources

This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.

Publication date: March 2009