There are a number of different classes of antidepressant. These include:
- selective serotonin reuptake inhibitors (SSRIs)
- monoamine-oxidase inhibitors (MAOIs)
- serotonin and noradrenaline reuptake inhibitors (SNRIs)
- noradrenaline and specific serotoninergic antidepressants (NaSSAs)
There are also other types of antidepressant medicines including agomelatine, a melatonin receptor agonist and a selective serotonin-receptor antagonist. All of these work well for moderate and severe depression but have different side-effects.
Your doctor will assess your symptoms and the potential side-effects and prescribe the most suitable medicine for you. Most people are prescribed an SSRI to start with since these generally have fewer side-effects and are the safest antidepressants. However, your doctor may prescribe other types of antidepressant if SSRIs haven’t worked or aren’t suitable for you.
The exact reasons why you may develop depression aren't fully understood at present. However, it's known that people with depression usually have reduced levels of certain brain chemicals called neurotransmitters, particularly two called noradrenaline and serotonin.
Neurotransmitters are released by nerve cells. They carry information across the tiny gap between one nerve cell and the next. Once they have done their job, neurotransmitters are re-absorbed into the nerve cell – this is called reuptake.
Antidepressants increase levels of serotonin and/or noradrenaline. The SNRIs, NaSSAs, tricyclics and MAOIs increase levels of both noradrenaline and serotonin, while SSRIs increase levels of serotonin only. These medicines work by either encouraging your nerve cells to make more of the neurotransmitters or by preventing their reuptake.
Tricyclic antidepressants (TCAs) delay the take up of noradrenaline and serotonin. This means there are more of these chemicals in your brain for longer. This is thought to help with depression. Amitriptyline, lofepramine and imipramine are examples of TCAs.
Other types of medicine, such as agomelatine, work on another chemical in your body called melatonin, as well as serotonin.
Antidepressants are only available with a prescription from your doctor. This may be from your GP or a psychiatrist (a doctor who specialises in identifying and treating mental health conditions). Antidepressants come as tablets or capsules and sometimes in a liquid form. It’s important to take your medicine as prescribed by your doctor.
It usually takes around two weeks before antidepressants start to have an effect and it can take up to six weeks for them to have a full effect. You will need to visit your doctor regularly when you first start to take antidepressants to see how well they are working. If they aren’t working well after four to six weeks, your doctor may consider increasing the dose or may prescribe you a different antidepressant to see if it works better for you.
If you find an antidepressant that works for you, you will probably need to carry on taking it for at least six months, even once your symptoms have gone away. This can help prevent depression coming back. You may need to take antidepressants for two years or more if you get repeated bouts of depression.
Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.
If you have heart problems, or if you're pregnant or breastfeeding, tell your doctor before you take an antidepressant. Certain antidepressants are safer for people who have heart problems, or for women who are pregnant or breastfeeding.
Side-effects are the unwanted effects of taking a medicine. If you have side-effects, it’s important to talk to your GP or the healthcare professional who prescribed your medicine before you stop taking it.
All antidepressants have some side-effects. Some side-effects, such as feeling sick and anxiety, are more common in the first week or two of treatment and often get better. Taking certain antidepressants can slow down your reaction speeds and affect activities that require concentration, such as driving. Ask your doctor whether it’s safe for you to drive while taking your medicine. All antidepressants can affect your sex life – talk to your GP if you’re worried about this.
Below we describe common side-effects for some of the main classes of antidepressants. This section doesn’t include every possible side-effect of antidepressants. Please read the patient information leaflet that comes with your medicine for more information and if you're worried about possible side-effects, ask your doctor for advice.
Selective serotonin reuptake inhibitors
Although SSRIs have some side-effects, they are generally less troublesome than those of other antidepressants and so are prescribed most often. In particular, they are less likely to make you feel drowsy or give you a dry mouth. Side-effects of SSRIs include:
- feeling sick or vomiting
- diarrhoea or constipation
- weight loss
- skin reactions, such as a rash
- dry mouth
Rarely, some people experience suicidal thoughts after starting SSRIs. If this happens to you, you must seek urgent medical attention.
Side-effects of SNRIs and NaSSAs tend to be similar to those of SSRIs.
Common side-effects of tricyclics include:
- difficulty sleeping
- drowsiness or tiredness
- dry mouth
- blurred vision
- difficulty passing urine
- weight gain (although some people lose weight)
Some of these side-effects settle down with time, so carry on taking your medicine if you get these symptoms. Don’t stop taking your antidepressants without speaking to your doctor first.
Rarely, tricyclics may also cause arrhythmias (heart palpitations) and fits. Because of this, they are used less often than SSRIs.
MAOI antidepressants can interact with other medicines and some common foods, and increase the risk of side-effects. Because of this, MAOIs aren't prescribed very often. If you’re taking a MAOI antidepressant, your doctor will give you a list of foods that you shouldn’t eat.
Side-effects of MAOIs can include:
- low blood pressure
- dry mouth
Antidepressants aren't addictive but you may get withdrawal symptoms (often referred to as discontinuation syndrome) if you stop taking them suddenly. Symptoms of sudden withdrawal include:
- feeling sick
- trouble sleeping
- feeling irritable
- chills or tingling or prickly skin
- anxiety and panic
If you want to stop taking antidepressants, talk to your doctor first. He or she may suggest that you reduce the dose slowly, over a period of weeks, as this can help to prevent withdrawal symptoms.
Antidepressants can interact with some over-the-counter medicines. For example, if you take SSRIs with painkillers, such as aspirin or ibuprofen, it can increase the risk of bleeding in your stomach. Always ask your GP for advice and read the patient information leaflet that comes with your medicine.
Herbal remedies contain active ingredients and may interact with other medicines or cause side-effects. Don’t start a herbal remedy without speaking to your doctor or pharmacist first. St John's wort, for example, which is sold as a herbal antidepressant, can be harmful if you take it with prescribed antidepressants and it can interact with other medicines, such as the contraceptive pill.
Examples of the main types of antidepressants are shown in the table below.
Each 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.
If you're not sure which medicine you have been prescribed, ask your pharmacist for advice.
Generic name Brand name Selective serotonin re-uptake inhibitors citalopram Cipramil escitalopram Cipralex fluoxetine Prozac fluvoxamine Faverin paroxetine Seroxat sertraline Lustral Serotonin and noradrenaline reuptake inhibitors duloxetine Cymbalta, Yentreve reboxetine Edronax venlafaxine Efexor Noradrenaline and specific serotoninergic antidepressants mirtazapine Zispin Tricyclic antidepressants amitriptyline Triptafen clomipramine Anafranil dosulepin Prothiaden doxepin Sinepin imipramine lofepramine nortriptyline Allegron trimipramine Surmontil Monoamine-oxidase inhibitors phenelzine Nardil isocarboxazid tranylcypromine
Are there any antidepressants that can be prescribed for children and teenagers?
Most antidepressants that are used to treat depression in adults aren't suitable for children and teenagers. If your child’s GP thinks that your child needs to take antidepressants, he or she will probably be prescribed fluoxetine (Prozac), which is the only antidepressant where the benefits of treatment are believed to be greater than the risks.
If your child has been diagnosed with depression, their GP will usually suggest a psychological or talking therapy such as counselling or cognitive behavioural therapy (CBT), before prescribing antidepressants. If this doesn't work and your child has moderate or severe depression, your child’s GP may consider antidepressants. Children with mild depression won’t be prescribed antidepressants. Your child should continue with psychological therapies even if he or she is taking antidepressants.
Fluoxetine (Prozac) is the antidepressant doctors usually try first in children and teenagers. Fluoxetine is the only antidepressant that has been shown to be effective for depression in children and teenagers and the benefits of treatment are believed to be greater than the risks. Your child’s GP will want to see him or her regularly to check that your child is making good progress and that the medicine isn't causing any serious side-effects.
If fluoxetine doesn’t help your child, their doctor may prescribe another antidepressant, such as sertraline or citalopram.
Can I drink alcohol if I'm taking antidepressants?
Don't drink alcohol if you're taking antidepressants because alcohol can make your depression worse, slow down your reactions and make you drowsy. Also, some antidepressants can’t be taken with alcohol because together they can cause serious side-effects.
If you're taking antidepressants, it’s safest not to drink alcohol. Alcohol on its own can make your depression worse, but it can also slow down your reaction speeds and make you drowsy if you're taking antidepressants. This can affect activities that require concentration, such as driving or operating machinery.
Don’t drink alcohol at all if you’re taking a monoamine-oxidase inhibitor such as phenelzine and isocarboxazid. Some alcoholic drinks, particularly red wine, can interact with your medicine, and cause serious side-effects. Low alcohol lagers and beers can also interact with your medicine, so don’t drink these either. Ask your doctor for more information.
I have postnatal depression. Can I take antidepressants while breastfeeding?
Yes, a number of antidepressants are thought to be safe for you to take while you’re breastfeeding. However, some antidepressants are believed to be safer for your baby than others. Your GP will be able to advise you on the best antidepressant for you.
If you take antidepressants while you’re breastfeeding, small amounts of the medicine can be passed on to your baby through your breast milk. If your GP thinks that you need an antidepressant, he or she will consider whether any of the medicine will be passed to your baby in your breast milk and if so, whether the medicine will be harmful to your baby. Some antidepressants are thought to be safer for your baby than others.
Selective serotonin reuptake inhibitors (SSRIs) are often prescribed to treat postnatal depression. The SSRIs sertraline and paroxetine are found in smaller quantities in breast milk compared with some other SSRIs.
Some antidepressants aren’t suitable if you’re breastfeeding. These include mirtazapine, venlafaxine, doxepin and nefazodone. There either isn’t enough research to show they are safe or they are known to be harmful. Doxepin for example, can cause sedation and breathing problems for your baby.
Don’t take St John's wort (which is sold as a herbal antidepressant) if you’re breastfeeding as there isn’t enough evidence to show that it’s safe for your baby.
Whatever antidepressant you take, your GP will want to check your baby regularly to ensure he or she isn't affected by the medicine.
If you have any concerns about taking antidepressants while breastfeeding, talk to your GP.
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- Depression clinical presentation. eMedicine. www.emedicine.medscape.com, published 4 December 2012
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- Joint Formulary Committee. British National Formulary. 65th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain; 2013
- Baldo P, Doree C, Molin P, et al. Antidepressants for patients with tinnitus. Cochrane Database of Systematic Reviews 2012, Issue 9. doi: 10.1002/14651858.CD003853.pub3
- Depression treatment and management. eMedicine. www.emedicine.medscape.com, published 4 December 2012
- Antidepressants. Royal College of Psychiatrists. www.rcpsych.ac.uk, published September 2010
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- Depression. NICE Clinical Knowledge Summaries, cks.nice.org.uk, published February 2010
- Assessment and management of depression in secondary care. Map of Medicine. www.mapofmedicine.com, published 13 January 2012
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