Mirtazapine

Keep taking mirtazapine as you get better, which can take a few months, and then continue taking it for another six to 12 months after that as advised by your doctor.

If your illness has come back, then you should keep taking mirtazapine for at least two years after getting better. This will help keep you well.

If you stop taking the mirtazapine too soon, there is more chance that your symptoms will come back.

Discuss with your doctor how long you should take mirtazapine before starting your treatment.

If you want to stop mirtazapine, speak to your doctor to make sure it is not too soon.

You will get the best effect from mirtazapine if you take it regularly at the dose prescribed by your doctor.

Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.

Mirtazapine is taken once a day. It is best to take it at bedtime because it can make you feel sleepy.

You can take your medicine before or after food.

For the plain tablets, swallow them whole with a drink of water or juice - if you chew them, they taste bitter. The plain tablets should also be swallowed whole with at least half a glass of water while you are sitting up or standing up. This is to make sure that they reach the stomach and do not stick in your throat.

For the orodispersible tablets (melts), peel off the cover from the blister pack rather than pushing the tablet through, so it does not break, then put the tablet on your tongue and let it dissolve there.

There may be a measuring syringe to use with the oral solution to help you get the dose right. Read the instructions before you use it.

You can add your dose of the oral solution to a glass of water.

If you forget your bedtime dose of mirtazapine and you remember in the morning, then it is probably best that you miss that dose. This is because mirtazapine can make you sleepy, so it is best not to take it in the daytime. Just take your next dose at bedtime as usual.

Do not take a double dose to try to catch up because this could cause you to have extra side effects.

Mirtazapine works best if you do not miss any doses. However, if you are not missing more than one dose each week, it is unlikely that there will be any problems.

If you forget to take your tablets for a few days, you may start getting your old symptoms back, or you may get withdrawal symptoms such as headache, dizziness, anxiety, or feeling sick. You should talk to your doctor about this.

Stopping this medicine quickly, or reducing the dose too much at once, may cause your old symptoms to come back. It may also give you unpleasant withdrawal symptoms including dizziness, agitation, anxiety, headaches and feeling or being sick. These are usually mild and go away after a few days.

Once you start taking mirtazapine, the brain adjusts to having a new level of noradrenaline and serotonin around. Withdrawal symptoms are not caused by the medication being addictive, it’s just your brain readjusting to a change in the balance of chemicals.

It is better to agree stopping with a doctor who will reduce your dose gradually over a few weeks.

If you have taken more mirtazapine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different.

Mirtazapine can make some people think about hurting themselves or taking their own lives. You must go straight to hospital with your tablets if you have any of these thoughts.

Mirtazapine can also cause rare but serious side effects: allergic reactions (difficulty breathing, swelling of your face or throat, itching skin lumps), and bone marrow problems (symptoms could be high fever, sore throat or mouth ulcers). Go to a hospital with your medicine if you get any of these symptoms.

Do not take mirtazapine if you have taken a monoamine oxidase inhibitor antidepressant (MAOI) like moclobemide, phenelzine, isocarboxazid or tranylcypromine in the last 14 days.

Stopping mirtazapine suddenly can cause unpleasant withdrawal effects. Go to your doctor if you want to stop, or if you are having these effects.

You might feel sleepy or dizzy, or less alert, in the first few days after taking mirtazapine. Do not drive a car, ride a bike or operate machines until you see how this affects you.

If you are pregnant, or thinking of becoming pregnant, please read the pregnancy, post-natal and breastfeeding section under the 'Side Effects' tab, as mirtazapine may affect the developing baby.

If you have taken more mirtazapine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different. Go to A&E. Take your medicine with you to show to the doctors. Tell them how much you have taken. Get a friend or family member to go with you, if you can, just in case you feel ill on the way.

You might get any of the following signs:

• feeling sleepy or disorientated
• having a fast heartbeat

If you have any thoughts of taking your own life or of other ways of hurting yourself, go straight to a hospital with your tablets. This may be a side effect, but you need urgent help. If you’re less than 25 years old, you’re more likely to be affected by this and it’s also more likely to happen at the beginning of your treatment.

Stop taking your mirtazapine and go to a doctor or hospital straight away if you get the following symptoms:

• feeling like taking your own life or hurting yourself (see above)
• raised temperature (fever), sore throat, or mouth ulcers. These could be symptoms of problems with blood-cell production in the bone marrow, which can leave you more vulnerable to infections. While rare, these symptoms can appear after four to six weeks of treatment
• yellowing of the skin and the whites of the eyes. This is called jaundice, and it can be a symptom of liver problems
• rashes, blotches, itching, blistering, redness, peeling, or ulcers on your skin, in your mouth, or in your genital area. These can be symptoms of a rare but serious skin reaction
• having fits (also known as convulsions or seizures)
• feeling very excited or ‘high'
• shivering, excessive sweating, restlessness, irritability, agitation, confusion, mood changes, high temperature (fever), fast heartbeat, diarrhoea, trembling, weird muscle movements (that you cannot control), overactive reflexes, or losing consciousness. These may be symptoms of a rare but serious condition called serotonin syndrome
• tiredness, confusion, headache, irritability, feeling or being sick (nausea and vomiting), and muscle twitching. These can be symptoms of a low level of sodium in your blood, but some of these are also symptoms of serotonin syndrome

Please do not be worried by the side effects listed on this page. Many people take mirtazapine without any side effects or with only a few mild side effects. If you think you might be getting a side effect from mirtazapine, then you should discuss this with your doctor, nurse, or pharmacist.

Young people aged under 18 are more likely than adults to put on weight, get an itchy rash, or get higher blood fat levels in blood tests, while taking mirtazapine.

Young people under 18 have an increased risk of trying to take their own lives, thinking about taking their own lives, and hostility (mostly aggression, oppositional behaviour and anger) when they take mirtazapine. Therefore, it is not licensed for people under 18 years.

Your doctor may decide that mirtazapine is the best medication for you to take, even if you are under 18. They will discuss the reasons for this decision with you and will talk to you about what to do if you experience side effects.

If you get any side effects not listed here please look at the patient leaflet in the medicine pack.

Don't stop taking mirtazapine until you talk to your doctor or you may get withdrawal symptoms as well.

Very common side effects of mirtazapine, affecting more than one in ten people, include:

• feeling hungrier and putting on weight
• feeling drowsy or sleepy

Common side effects, affecting up to one in ten people, include:

• not feeling like doing anything (lethargy) or feeling tired
• feeling dizzy or shaking
• feeling confused or anxious
• feeling or being sick
• diarrhoea (loose poo)
• rash or skin problems
• joint or muscle pain
• feeling dizzy or faint when you stand up suddenly
• swelling of the feet or ankles caused by fluid retention
• sleep problems and unusual dreams