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Tricyclic antidepressants (TCAs)

Tricyclic antidepressants (TCAs) help treat depression, anxiety, panic attacks and social phobia. They can also help with obsessive compulsive disorder (OCD) and some types of pain.

Examples of TCAs are amitriptyline, clomipramine, imipramine and nortriptyline.

Talking therapies are often used alongside antidepressant medication.

Health professionals believe that antidepressants work by increasing the activity of neurotransmitters. Neurotransmitters are chemicals in our brains. Certain neurotransmitters, such as serotonin and noradrenaline, affect mood and emotion.

Neurotransmitters may also affect pain signals sent by nerves. That could explain why some antidepressants can help relieve long-term pain.

How soon TCA antidepressants work

You may start on a low dose of a TCA then slowly increase over several weeks to a target dose. This is to reduce the chance of side effects.

It can take between 4 and 6 weeks on your target dose before you get the full effect.

TCA antidepressant safety

It is usually safe to take TCA antidepressants as prescribed by your doctor. But they do not suit everyone. Let your doctor know if you have the following, as extra care may be needed:

Discuss any other medicines you take with your pharmacist or health care provider. This should include any you buy yourself. Especially cold remedies and hay fever medicines. It should also include nutritional or herbal supplements. And complementary medicines such as St John's wort. This is because other medicines may cause problems with your antidepressants.

You should avoid alcohol when taking TCAs. This can cause drowsiness and make depression worse. TCAs combined with alcohol can impair driving.

Side effects from TCA antidepressants

Important

Rarely, antidepressants can make you more anxious and restless in the first 2 weeks of taking them. You can even have feelings of self-harm or suicidal thoughts. If this happens, talk to your healthcare provider. Or contact a mental health crisis support line.

Side effects from TCAs are usually mild and do not last long. Some people will not have any side effects.

If you have minor side effects, try staying on the medicine for a few weeks. Minor side effects often go away after your body gets used to the new medicine.

If the side effects do not go away or if they are worrying you, tell your healthcare provider or pharmacist. They may have suggestions for how to reduce or manage your side effect.

Common side effects of TCAs include dry mouth, constipation and trouble passing urine. They also include sleep problems and less interest in or trouble having sex.

Stopping antidepressants

There is no set time for how long you should take antidepressants. Most people will need to take them for at least 6 to 12 months. This can help stop your symptoms coming back.

Antidepressants are not addictive. But if you stop taking them suddenly, you may get some symptoms. This is known as antidepressant withdrawal or discontinuation syndrome.

You need to decrease most antidepressants slowly. You may need to drop the dose by small amounts each week, or every two weeks or every month.

You should talk to your healthcare provider before stopping your medication. They will help you make a plan for how you are going to do this.

For more information, see Stopping antidepressants.

Written by HealthInfo clinical advisers. Page created December 2023.

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