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About mirtazapine

Mirtazapine is an antidepressant medicine. It's used to treat depression and sometimes obsessive compulsive disorder (OCD) and anxiety.

It works by increasing the amount of mood-enhancing chemicals called noradrenaline and serotonin in your brain.

Mirtazapine is only available on prescription. It comes as tablets, tablets that dissolve in your mouth or as a liquid that you swallow.

Key facts

  • Mirtazapine usually takes about 4 to 6 weeks to work.
  • Common side effects include headaches, dry mouth and feeling sick. They're usually mild and go away after a couple of weeks.
  • If you and your doctor decide to take you off mirtazapine, your doctor will probably recommend reducing your dose gradually to help prevent extra side effects.
  • Mirtazapine is not a sleeping tablet but it can make you feel sleepy. This can be helpful if you have depression and difficulties getting to sleep.

Page last reviewed: 15 February 2022
Next review due: 15 February 2025