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About mirtazapine

Mirtazapine is an antidepressant medicine.

It's only available on prescription. It comes as tablets, including tablets that dissolve in the mouth (orodispersible).

Brand names available in Ireland are Mirap, Zismirt and Zispin.

Uses for mirtazapine

Mirtazapine is used to treat depression.

Your GP may also prescribe it for obsessive compulsive disorder (OCD) or anxiety disorders. This is known as off-label use. Talk to your GP or pharmacist about off-label use.

Off label - what it means

Off-label use is when a medicine is prescribed in a way that is different to how it was first licensed.

Your GP may prescribe a medicine off label if they think it will treat your condition effectively.

They prescribe the medicine in a different way than described on the patient information leaflet, such as:

  • for a different age group
  • to treat another condition
  • at a higher or lower dosage

Off-label use does not mean that the medicine is unsafe. Your GP will tell you if they are prescribing the medicine off label. They will only prescribe it if the benefits outweigh any risks.

Talk to your pharmacist or GP if you have any concerns or questions about off-label use.

When you start taking mirtazapine

It may take 2 to 4 weeks before you start to feel better after taking mirtazapine. Tell your GP if you do not feel better or feel worse after 2 to 4 weeks.

Mirtazapine is not a sleeping tablet but it can make you feel sleepy. This can be helpful if you have depression and find it hard to sleep.

If you are depressed, you can sometimes have thoughts of harming yourself. These may be increased when you first start antidepressants, as these medicines take time to work.

Emergency action required: Call 112 or 999 or go to an ED immediately if:

  • you have thoughts about harming yourself or ending your life

Page last reviewed: 3 July 2024
Next review due: 3 July 2027