Mirtazapine

What mirtazapine is for

Mirtazapine is used to treat depression.

It's thought to work by increasing the levels of chemicals in your brain that affect your mood, such as serotonin. This can improve your mood and reduce negative thoughts.

How to take mirtazapine

Mirtazapine can be taken as:

• tablets that you swallow with a glass of water
• tablets that melt on your tongue (orodispersible)
• a liquid (oral solution) that you swallow – this comes with a spoon or syringe for you to measure the correct dose

Your doctor may prescribe a low dose to start with and increase it after a few weeks or so. This reduces the chances of side effects.

You'll usually take mirtazapine once a day before bedtime, as it can make you sleepy.

Your doctor may split your daily dose into 2 doses. Take the smaller dose in the morning and the larger dose before you go to bed.

Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.

Mirtazapine usually starts working after 1 or 2 weeks and you'll usually take if for at least 4 to 6 months. Tell your doctor if you're not starting to feel better after 2 to 4 weeks.

If you miss a dose of mirtazapine

What to do if you miss a dose of mirtazapine depends on whether you're taking 1 or 2 doses a day.

If you take mirtazapine once a day:

• skip the missed dose and take the next dose at the usual time
• do not take 2 doses to make up for a forgotten dose

If you take mirtazapine twice a day:

• if you forget your morning dose, take it with your evening dose
• if you forget your evening dose or both doses, skip them completely and take the next dose at the usual time the next day

If you take too much mirtazapine

Taking an extra dose of mirtazapine can be dangerous.

How to stop taking mirtazapine

Your doctor may suggest that you stop taking mirtazapine if you've been feeling better for some time.

But do not stop taking it suddenly because it can cause withdrawal symptoms. If you want to stop taking mirtazapine, speak to your doctor first.

Your doctor will gradually reduce your dose over a few weeks or months. Always follow your doctor's advice.

Side effects of mirtazapine

Like all medicines, mirtazapine can cause side effects, although not everyone gets them.

Most side effects should ease after a couple of weeks as your body gets used to the medicine, but some can last longer.

Common side effects

Common side effects of mirtazapine include:

• feeling drowsy or sleepy
• headaches
• a dry mouth
• feeling like you want to eat more than usual and putting on weight
• feeling dizzy or shaky
• feeling sick (nausea) or being sick (vomiting)
• diarrhoea

If you feel sleepy or cannot concentrate after taking mirtazapine, do not drive, ride a bike or use machinery until these symptoms have gone away and you feel completely alert.

Serious side effects

Mirtazapine can sometimes cause more serious side effects, although most of them are rare.

Possible serious side effects of mirtazapine include:

• an allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised, itchy rash and difficulty breathing
• having thoughts about suicide or harming yourself
• feeling unusually high or like you have lots of energy (mania) – this can affect how you behave, for example you may take more risks or do things you would not usually do
• liver problems – the whites of your eyes may turn yellow, or your skin turns yellow (this may be less obvious on brown or black skin)
• signs of an infection, such as a high temperature, sore throat and mouth ulcers – these could be due to a problem with your blood cells

Who can and cannot take mirtazapine

Most adults can take mirtazapine.

Mirtazapine is not suitable for everyone. For example, it's not usually recommended for anyone under 18 years.

It may also not be suitable if you have:

• ever had an allergic reaction or serious side effect from mirtazapine
• liver, kidney or heart disease
• epilepsy
• diabetes
• schizophrenia

Before taking mirtazapine, tell your doctor if you have any other medical conditions.

Breastfeeding and mirtazapine

Tell your doctor if you're breastfeeding.

Mirtazapine is sometimes used while breastfeeding. It only passes into your breast milk in very small amounts.

You may be able to continue taking it if the benefits outweigh any possible risks. Your doctor might suggest switching to another antidepressant instead.

It's rare for breastfed babies to get side effects from mirtazapine, but speak to a healthcare professional or call NHS 111 if you have any concerns about your baby.

Pregnancy and mirtazapine

Tell your doctor if you're pregnant or you get pregnant while taking mirtazapine.

Mirtazapine can be used during pregnancy if needed. Your doctor will talk to you about the risks and benefits of taking it while you're pregnant.

You may be advised to give birth in hospital so you and your baby can be closely monitored after you've given birth.

Find out more about taking mirtazapine during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

Taking mirtazapine with other medicines, food and drink

There are some medicines, remedies and supplements that may not mix well with mirtazapine.

This includes some types of:

• antidepressants, such as monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors (SSRIs)
• opioids, such as morphine and medicines containing buprenorphine
• painkillers, such as ibuprofen
• epilepsy medicines, such as carbamazepine
• medicines that relax your muscles, such as benzodiazepines

Do not use the herbal supplement St John's wort when taking mirtzapine.

Before taking mirtazapine, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.

Food, drink and alcohol

You can eat and drink normally when taking mirtazapine.

It's best not to drink alcohol when taking mirtazapine because it can increase the risk of side effects, such as making you feel very drowsy.