Information on Antidepressants
by Dr Sarah Kennedy

Introduction

Depression is a common illness and is different from the usual ups and downs of every day life. For more information visit our page on depression.

Like other illnesses Depression can respond well to the right treatment. For some people this may be without medicine, for instance, with “talking treatments” such as counselling or psychotherapy and for others successful treatment is with an antidepressant. Some will benefit from a combination of these two forms of treatment. Most people will be treated by their GP, while others may be offered help and advice from a psychiatrist or mental health nurse.

This next part contains some answers to commonly asked questions about antidepressants. If the information you are looking for is not discussed here, there is a list of other resources at the end of the section which may help. It is always important to remember that any question related to your own illness and treatment may be best answered by your doctor. If there are things you do not understand or want explained to you, ask!

What Are Antidepressants?

Antidepressants have been around since the 1950’s. Over the years the list of antidepressants has grown and to date, over 30 different kinds are available in the UK. They work by influencing the balance of chemicals or “neurotransmitters” in the brain which are thought to be important in depression – serotonin and noradrenaline being the best understood. Antidepressants can be classified into five main groups (see below) based on how they work on the brain's neurotransmitters.

Each antidepressant will have specific characteristics such as how many times a day they need to be taken, what dose is required to be effective (100 mg of one kind of antidepressant may be a less strong dose than 10 mg of another) and what are its typical side effects.

What Are Antidepressants Not?

Antidepressants are not tranquillisers, sleeping tablets or stimulants. In days gone by, people with depression were often prescribed sedating medications on which they could become dependant. Antidepressants are not addictive and can be free of any sedative effect, though some may cause significant sedation in some individuals.

What Other Conditions Do Antidepressants Treat?

Antidepressant medicines, despite the name, are also known to be effective for the following conditions:-

• Post traumatic stress disorder
• Severe anxiety and panic attacks
• Chronic pain
• Obsessive compulsive disorder
• Eating disorders

If you are unclear why an antidepressant has been suggested for you, ask your doctor.

Do They Work?

There is no shortage of evidence showing that antidepressants are effective in treating depression. Different studies quote different figures, but broadly speaking around 60% of people with depression will improve taking an antidepressant. Interestingly, around half these people would improve if they were unknowingly prescribed a dummy pill or placebo and this is higher than if they had received nothing at all. This “placebo” effect occurs with many other types of medicines including painkillers. Placebo medicines can only be prescribed to people who have consented to a medical trial and are therefore not used in daily practice.

What Are The Different Kinds?

Most antidepressants fall into one of five main categories. Within each of these categories, the individual antidepressants work in a similar way and therefore have similar side effects. The following list includes most of the commonly prescribed antidepressants and which group they belong to.

TCAs (Tricyclic Antidepressants)

Tricyclics are so named because of their chemical structure, and have been in use since the 1950s. This class of drugs includes Amitriptyline (Tryptizol), Imipramine (Tofranil), Clomipramine (Anafranil), Lofepramine (Gamanil), Nortriptyline (Allegron), and Dosulepin (Prothiaden).

SSRIs (Selective Serotonin Reuptake Inhibitors)

SSRIs are a type of antidepressant marketed in the UK since 1989. They block the re-uptake of serotonin into the nerve cell that released it, thereby prolonging its action. These drugs include Fluoxetine (Prozac), Paroxetine (Seroxat), Citalopram (Cipramil), and Sertraline (Lustral)

MAOIs (Monoamine Oxidase Inhibitors)

MAOIs are an older type of anti-depressant which are not prescribed so much these days because of dietary restrictions. MAOIs include Phenelzine (Nardil), and Tranylcypromine (Parnate). Moclobemide (Manerix) is a newer “reversible” MAOI that has less stringent dietary restrictions

SNRI's (Serotonin and Noradrenaline Reuptake Inhibitors)

These drugs slow the re-uptake of both noradrenaline and serotonin and thus prolong their action. Venlafaxine (Efexor) was the first SNRI and Duloxetine (Cymbalta) is the most recently licensed anti-depressant, which was released in Scotland in 2006.

NASSA's (Noradrenaline and Selective Serotonin Antagonists)

Mirtazapine (Zispin) is similar to the tricylics but has fewer side effects than the older drugs.

Others

Reboxetine (Edronax) is a Selective Noradrenaline Reuptake Inhibitor (NARI). Mianserin and Trazadone (Molipaxin) are related to TCAs.

Until the 1990’s Tricyclics were the most commonly prescribed antidepressants but now the substantial majority of antidepressant prescriptions are for SSRIs.

Questions and Answers

Q. Where can I get more information about my particular antidepressant?

A. If you are on an antidepressant, you should find detailed information about your treatment on the “data sheet” that the pharmacist gives you with your medication. You should read this information carefully before starting your treatment and keep it handy to refer to later as required.

Q. What about side effects?

A. Like all medicines, antidepressants can cause side effects. Unfortunately it is not possible to predict who will get these side effects or how bad they will be. Side effects can vary considerably between individuals. Do not be put off the drug your doctor has prescribed simply because a friend or relation had a problem with it. There is a good chance that you will not have the same problem.

Even with a commonly used drug that can be bought over the counter, such as Aspirin, a list of all its known side effects can be worrying. It is therefore reassuring to know that:

• Only a minority of persons on an antidepressant find it necessary to stop their treatment because of side effects. In clinical trials of  antidepressants, typically 15-20% of patients will stop their treatment because of side effects.
• Side effects from antidepressants tend to be at their worst in the early stages of treatment. So, if you experience some mild or even  moderate side effects, it may be worth persevering with your treatment to see if the side effects will settle. Your doctor will be able to advise you on this.
• The side effects caused by antidepressants are, almost invariably, ones that you will be aware of, such as nausea or headache.  Potentially serious side effects that you are unaware of are rare on antidepressants.

If you are worried about any side effect, speak to your doctor or pharmacist.

Q. Do side effects depend on the type of antidepressant?

A. Yes. The main area where antidepressants differ is with respect to the side effects you might experience when taking them. The information below merely gives an indication of typical side effects. For full details you should study the data sheet provided with your medication.

• TCAs Common problems with Tricyclics include a dry mouth, constipation, a slight tremor, a more rapid heart beat, sleepiness and  increased appetite. Men may experience sexual difficulties – either difficulty getting an erection or delayed ejaculation. They tend not to be  well tolerated by the elderly and they are very dangerous in overdose.
• SSRIs Particularly in the first week or two SSRIs may cause nausea or even sickness and sometimes they may increase feelings of  anxiety. They can cause problems with sexual function in both men and women. Overall the SSRIs are less prone to unpleasant side  effects than the Tricyclics and they are much less dangerous in overdose.  
• MAOIs These are now rarely prescribed because of the dietary restrictions they impose. They can cause dangerous increases in blood pressure when taken with cheese and other foods containing Tyramine.
• SNRIs Venlafaxine is similar in its side effects to the SSRIs. It should not to be used in the presence of severe heart problems and it can increase blood pressure which should therefore be monitored. 

Q. What if I have other medical conditions or drug treatments?

A. Certain medical conditions may be a contraindication to some antidepressants. Similarly, some medications may have potentially serious interactions with particular antidepressants. Nevertheless, whatever your medical problems or treatment it will normally be possible to find an antidepressant that is safe for you to take. It is essential that the doctor managing your antidepressant treatment should be fully aware of your past and present medical problems and of any medication you are taking. If you have any concerns, be sure and check that the doctor is aware of all your relevant medical details. 

Q. Are some antidepressants more effective?

A. Generally there is no difference between antidepressants with regard to effectiveness. In other words, no one antidepressant is stronger, or more likely to get you well, than another. Different antidepressants may work better for different people, so if the first one you try does not seem to be effective, it can be very worthwhile to try another.

Q. What will happen to me when I start taking my antidepressant?

A. All antidepressants work slowly. The benefits tend to be felt over weeks rather than days and different symptoms will get better at different times. Most people start to feel some improvement after 2-3 weeks, however the full effect usually takes around 4-6 weeks. It is important to continue taking your antidepressant so that the full benefit can be felt. Unfortunately, side effects commonly occur before mood starts to improve. Some people will not experience any side effects whereas other may experience them more extremely. You should be made aware before starting your tablets which side effects might be expected, but if you are uncertain about anything when starting the tablets, you should consult your doctor, nurse or pharmacist.

Q. What if I miss a dose?

A. Never change your dose without checking with your doctor. If you forget a dose, take it as soon as you remember as long as it’s within a few hours of the usual time – if it is not, wait until the following day and take it as you would normally.

Q. When I feel better can I stop taking them?

A. No. If you stop taking an antidepressant, your original symptoms may return. In starting an antidepressant, it should be viewed as embarking on a course of treatment. To reduce the chance of becoming depressed again, they should be taken for at least a further 6 months after you start to feel better and often longer. You should not stop or reduce medication without speaking to your doctor first.

Q. When are long term antidepressants advised?

A. Some people will experience Depression as a single episode of illness but it can be a recurring problem. The good news is that antidepressants are helpful in preventing new episodes of Depression as well as in treating existing episodes. Preventative use of an antidepressant should be considered for anybody who has shown a tendency towards recurrent Depression. Just when the decision is taken will be a matter for discussion between the individual and his or her medical adviser. Generally, anybody who has experienced three episodes of Depression, or two episodes in quick succession, is likely to do better on long term preventative treatment.

Q. Is it safe to take an antidepressant long term?

A. With any long term medication it is important to carefully weigh up the benefits against any possible problems. This is something that your GP or specialist adviser should help you with. Fortunately it is rare for adverse effects of antidepressant use to emerge late in treatment. Generally antidepressant side effects manifest early in treatment and will be very apparent.

Q. Can I get dependant on an antidepressant?

A. Antidepressants do not cause the addiction that happens with tranquillisers (and with nicotine, alcohol or heroin) whereby there is a need to keep increasing the dose to get the same effect and there is a craving for the drug when it is stopped. However, it has become apparent that up to one third of people who stop their SSRI or SNRI have withdrawal symptoms. Usually these are mild but they can be severe for some people. Paroxetine (Seroxat) and Venlafaxine (Efexor) are most likely to be associated with withdrawal problems. The symptoms include: anxiety, dizziness, vivid dreams and bodily sensations like electric shocks. To reduce the risk of withdrawal symptoms the dose of certain antidepressants should be tapered off rather than stopped abruptly. Your doctor will advise you on this.

Q. Can antidepressants increase the risk of suicide or violent behaviour?

A. There is some evidence of increased suicidal thoughts, though not of an increase in actual suicide, in young persons on SSRIs but not in persons over 18 years. There have also be reports of an increase in aggressive behaviour in the early stages of treatment with an SSRI but such episodes are rare.  If you are concerned, speak to your doctor as soon as possible.

Q. Can I drink?

A. It is generally recommended that anyone taking an antidepressant should not take alcohol. The combination of any antidepressant with alcohol may cause drowsiness and increase the risk of falls and accidents. Also, very importantly, drinking alcohol usually makes depression worse. Excessive drinking is especially likely to do this. Once people are used to their medication, they can sometimes drink alcohol in small amounts without any problems. Avoid alcohol for the first 1-2 months, after this, if you want to drink, try a glass of your normal drink and see how you feel – if it doesn’t make you feel drowsy then it’s probably OK to drink small amounts. It pays to be cautious as alcohol affects different people in different ways, especially when they are taking medication. Never stop your medication because you fancy a drink at the weekend and never drink any alcohol and drive when on an antidepressant.

Q. Can I drive?

A. Some antidepressants may cause you to feel sleepy or drowsy, particularly in the early stages of treatment. When starting treatment you should talk to your doctor about when it will be safe for you to drive or operate machinery. Once you are established on your treatment, driving will not normally be discouraged. You should advise your car insurance company that you have started an antidepressant.

Q. What about antidepressants for the old or young?

A. SSRIs are not licensed for persons under 18 although the National Institute for Clinical Excellence (NICE) has advised that the SSRI Fluoxetine (Prozac) can be used. Depression is common in later life and antidepressants may be very helpful. However, they should be used with great care since the elderly may be more at risk with some side effects, for example sedation, and they are more likely to have physical illnesses which may contraindicate the use of some antidepressants. 

Q. What about antidepressants in pregnancy or breastfeeding?

A. It is always best to take as little as possible in the way of medication during pregnancy, especially in the first 3 months, however some mothers do take antidepressants when they are pregnant. There is some evidence that babies of mums on these medications may experience withdrawal symptoms after birth. Paroxetine (Seroxat) seems to be the antidepressant most likely to do this. Doctors are advised to consider alternative treatments in pregnancy but for some people, the risk of becoming depressed or remaining depressed may outweigh the possible risks associated with the medication. This is a very personal decision and is something your doctor and you should discuss together. For breastfeeding mums on antidepressants babies will only get, at most,  a small amount of antidepressant from their mothers milk. Some antidepressants are better than others in this regard. On balance, bearing in mind all the advantages of breastfeeding, it may be best to carry on whilst taking your antidepressant. Again this is a decision which should be thoroughly discussed with your doctor.

Q. What happens if I choose not to take an antidepressant? 

A. This is a difficult question to answer as it depends on how severe the Depression is and how long it has been present. Around 80% of Depressions naturally resolve themselves within 8-12 months. If your Depression is mild, it is best to try some other treatments. The National Institute for Clinical Excellence (NICE) advise against antidepressant use for mild Depression. However, antidepressants have revolutionised the way Depression is managed. They can limit the severity and duration of the depressive illness and increase the speed of recovery. If you can’t decide, it is best to talk it over with your doctor or nurse.

What Other Treatments for Depression Are Available?

Treatment for Depression can involve a variety of different approaches and often people find that a combination of these works best. There is no “golden rule” or “one size fits all” for the treatment of Depression and for some people it can take time to work out what works best for them. For more information on the various treatment options available, visit our page on the treatment of depression

Finally……..

If you are not sure about why you have been suggested an antidepressant or have specific questions about your treatment, it is always important to ask whoever has advised it for you. Depression can be treated successfully! Antidepressants are proven to help reduce  the severity of symptoms, hasten recovery and protect against relapse but are not the only answer. Avoiding stress and worry and lack of sleep, healthier lifestyle choices and being able to talk things through with someone who can listen and support you call all play a major role in getting better.

Further information

Royal College of Psychiatrists information sheet on anti-depressants

Drug Treatment Leaflets Scottish Association For Mental Health (SAMH). Includes leaflets on Tricyclic and SSRI antidepressants

Making Sense of Antidepressants - Mind booklet

Net Doctor Anti Depressants Page Information about the various anti-depressants as well as other medication you may be prescribed

Norfolk Mental Health Care NHS Trust Pharmacy Medicine Information. This website provides information about antidepressants
 
Official Patient Information Leaflets

The British National Formulary - the information manual on medication used by UK doctors

UK Psychiatric Medication Helpline 020 3228 2999

References

• Royal College of Psychiatrists information sheet on anti-depressants http://www.rcpsych.ac.uk/mentalhealthinformation/mentalhealthproblems/depression/antidepressants.aspx
• Antidepressant drugs and generic counselling for treatment of major depression in primary care: randomised trial with patient preference.
  British Medical Journal 2001; 322:772 (31 March) Compares antidepressants and counselling.
• Antidepressant discontinuation reactions.
  British Medical Journal 1998; 316:1105-1106 (11 April)
• Depression in primary care, Vol 2. Treatment of major depression
  Rockville, MD: US Department of Health and Human Services, 1993 (Clinical practice guidelines No. 5). A review of the effectiveness of antidepressants and other treatments of depression.
• Pregnancy and breastfeeding:
  Motherisk (www.motherisk.org) a good quality web site listing information about drugs in pregnancy and breastfeeding.
• Information on antidepressant safety from the Medicines and Healthcare products Regulatory Authority (MHRA), part of the UKs Department of Health www.mhra.gov.uk/home/idcplg?IdcService=SS_GET_PAGE&nodeId=242
• Paroxetine safety in pregnacy - frequently asked questions www.mhra.gov.uk/home/groups/pl-p/documents/websiteresources/con2022700.pdf