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Antidepressants

Antidepressants are medicines used to help treat certain mental illnesses. These include depression, anxiety and panic attacks. They can also help with some cases of eating disorder, chronic (persistent) pain, obsessive compulsive disorder (OCD) and post traumatic stress disorder (PTSD).

How antidepressants work

Antidepressants work by increasing the activity of neurotransmitters. Neurotransmitters are chemicals in our brain such as serotonin and noradrenaline, that affect mood and emotion. Talking therapies are often used alongside antidepressant medication. 

Prescribing antidepressants

Your healthcare provider will consider these things when choosing which antidepressant to prescribe.

  • The type of your illness and how severe it is.
  • Whether you have other medical conditions.
  • Other medicines you might be taking.
  • Your response to antidepressant medicines in the past.
  • Possible side effects.
  • If you are pregnant or breastfeeding.

Some people respond better to one antidepressant medicine than another. You may need to try different ones before finding the one that works best for you. 

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  • SSRIs help treat certain mental illnesses and are usually the first choice for moderate to severe depression. They have fewer side effects and help most people who try them.

    SSRIs are also used to treat anxiety, panic attacks, social phobia, eating disorders and obsessive compulsive disorders (OCD).

    Examples of SSRIs include:

    • citalopram
    • fluoxetine
    • sertaline.

    SSRI antidepressant safety

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

    • Liver or kidney problems or drink alcohol heavily.
    • Diabetes.
    • Heart problems or bleeding disorders.
    • Seizures, fits or convulsions.
    • You are pregnant, breastfeeding or wish to become pregnant.

    See mymedicine.nz for information about particular medicines

  • SNRIs are used to treat severe depression, anxiety disorder or panic disorder. They are usually tried when SSRIs have not been successful

    Venlafaxine is the SNRI used in New Zealand.

    See mymedicine.nz for information about particular medicines

  • Tricyclic antidepressants (TCAs) are not usually used to treat depression due to their side effects. They are most used to treat pain and anxiety. 

    TCA antidepressant safety

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

    • Liver, kidney or prostate problems.
    • Diabetes.
    • A rare tumour of the adrenal glands (phaeochromocytoma).
    • Glaucoma.
    • Heart or thyroid problems.
    • Seizures, fits or convulsions.
    • You are pregnant, breastfeeding or wish to become pregnant.

    See mymedicine.nz for information about particular medicines

  • MAOI antidepressants are used when depression has not responded to other medication. They are rarely prescribed because of their side effects and interactions with food.

    MAOI antidepressant safety

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

    • Heart or liver problems.
    • Diabetes or hyperthyroidism.
    • Seizures, fits or convulsions.
    • A rare tumour of the adrenal glands (phaeochromocytoma).
    • A group of rare disorders that affect the skin and nervous system (porphyria).
    • You are pregnant, breastfeeding or wish to become pregnant.

    Side effects from MAOI antidepressants

    Foods and drinks that contain tyramine can interact with MAOI antidepressants. This can cause your blood pressure to rise suddenly. You may experience a severe headache, chest pain and increasing shortness of breath. If you have this reaction, you will need to go to the emergency department at the hospital. 

    See mymedicine.nz for information about particular medicines

Side effects of antidepressants

Common minor side effects of antidepressants include:

  • nausea
  • diarrhoea
  • sleep problems
  • sexual problems
  • sweating  
  • dry mouth. 

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.

Rare side effects

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. 

Taking antidepressants

Most antidepressants start helping within 2 weeks of starting to take them. It usually takes between 4 and 6 weeks before you get the full effect. If you do not feel any better after 2 to 4 weeks, tell your health professional. You may need to increase your dose or change to another antidepressant.

Most people take 1 antidepressant at a time. Some people may need to use 2 antidepressants in combination.

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. 

General safety when taking antidepressants

Discuss any other medicines, nutritional or herbal supplements you take with your pharmacist or healthcare provider. This should include any you buy yourself especially:

  • cold remedies
  • hay fever medicines
  • St John's wort.

This is because other medicines may cause problems with your antidepressants. 

It is best to avoid alcohol when taking antidepressants.

Stopping antidepressants

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 2 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. 

Stopping antidepressant medicines - Medsafe (external link)

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