What it is used for

Depression

Read our guides:

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

Anxiety
Sleep problems linked to depression
Poor appetite and weight loss in older people

How it works

Mirtazapine blocks certain receptors in the brain, which increases the release of serotonin and noradrenaline. It also blocks histamine, which is why it causes sleepiness and increased appetite.

Side effects

Like all medicines, Mirtazapine can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

feeling sleepy in the first few weeks
increased appetite and weight gain
dry mouth
headache
dizziness

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

a high temperature, sore throat or mouth ulcers, which can be signs of a low white blood cell count
thoughts of harming yourself
yellowing of the skin or eyes
a severe skin rash

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

It is usually taken at bedtime.
Lower doses can be more sedating than higher doses.
Avoid alcohol.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.