Olanzapine

Your doctor will advise you on how long it is best to keep taking your medication. This may vary depending on what you’re taking it for and how many times you’ve been unwell.

Many people take olanzapine for a few years.

For psychosis or schizophrenia, if you have had one episode of illness, then it is best for you to keep taking olanzapine for at least two years to reduce the chances of becoming ill again. If you have had more than one episode of illness, then a period of at least five years is recommended.

If you are taking olanzapine to treat bipolar mania or bipolar depression, then you will need to discuss long-term medicines for your bipolar disorder with your doctor. This is to help stop the illness coming back.

For bipolar disorder, it is important to remain on medicines in the long term because every time you become ill, there is more chance of you becoming ill again. Olanzapine can be used as a long-term medicine, but there are other choices too, and lithium is still thought to be the best long-term medicine for bipolar disorder. You should discuss your options with your doctor.

For schizoaffective disorder, it is probably best to keep taking the olanzapine for several years to reduce the chances of the illness coming back. We know less about schizoaffective disorder, but it has some similarities to bipolar disorder and some similarities to schizophrenia.

Depression is usually treated with an antidepressant medicine, and olanzapine is sometimes added to an antidepressant for more severe depression. For people with severe depression, it is best to continue the antidepressant medicine for at least two years to stop the illness from coming back. The doctor is likely to recommend continuing olanzapine for the same length of time. Your doctor should review your progress on this medication at least once a year.

You will get the best effect from olanzapine if you take it every day at the dose prescribed by your doctor.

You may start with a low dose that increases slowly to your regular dose over the next few days.

You will usually take your dose once a day.

It is usually recommended to take olanzapine at bedtime because it can cause sleepiness as a side effect. However, it is important to choose a time of day to take it that you can easily remember, which could be bedtime, a mealtime, or when you brush your teeth.

You can take it before or after food.

For the plain-coated tablets, swallow them whole with a drink of water – if you chew them, they taste bitter.

Put orodispersible tablets on your tongue and let them dissolve there. You can also dissolve these in a glass of water, orange juice, apple juice or milk and then drink it all down straight away.

If you receive your medicine by injection, a doctor or nurse will administer the olanzapine injection into a muscle in your bottom. This provides a long-lasting dose of olanzapine, lasting for two or four weeks. If you have just switched to the injection you may need to take tablets alongside this while the dose builds up. Every time you have the injection, you will be asked to wait at the centre for at least three hours. This is to check you do not have any unwanted reactions to the injection. The good thing about a long-acting injection is that you don’t have to remember to take so many tablets every day. It is slowly working in your body all the time between injections. The injection should switch between the left and the right side so that it’s not given in the same place all the time.

If you remember later during the day, take it as soon as possible.

If you forget to take it by your next dose, just take the next dose at the correct time. Do not try and catch up on missed doses by taking a double dose.

If it is less than 12 hours before your next dose of olanzapine, then do not take the missed dose because taking the doses too close together could cause more side effects.

If you miss your appointment for your injection, contact your doctor or nurse straight away to make another appointment.

It is very important to have the injection at the frequency prescribed for you, usually every two or four weeks.

If you forget to take your tablets for a while, or you miss an injection, you may start getting your old symptoms back or get withdrawal symptoms. You should talk to your doctor if this happens.

Regularly forgetting to take your medication can increase the risk of you becoming ill again and may mean that your symptoms could be worse if you become unwell again.

If you are struggling to remember to take your medication regularly as prescribed by your doctor, speak to your pharmacist and doctor for advice to help you.

Stopping olanzapine too soon after you have recovered may increase your risk of becoming unwell again. Discuss stopping your medication with your doctor. Planning and support are important to stopping olanzapine successfully.

Olanzapine is not addictive, but if stopped suddenly or the dose you are taking is reduced too much at once, you may experience withdrawal symptoms. These are caused by the receptors and levels of chemical transmitters in your brain readjusting after you reduce or stop your medication.

Some of the symptoms you get may be like symptoms you had when you were unwell, so understandably, you may feel anxious or upset that your illness could be returning.

Withdrawal symptoms usually start within a few days of stopping (or sometimes reducing) your medication. A wide range of symptoms have been reported. You may experience a few or a range of these:

• difficulty getting to sleep or disturbed sleep
• low mood, feeling anxious or agitated or restless
• dizziness or light-headedness
• headaches
• reduced concentration or feeling confused
• feeling sick or being sick, diarrhoea
• flu-like symptoms
• tense or jerky muscles and slow movements
• uncontrollable movement of face or body
• hallucinations, intrusive thoughts (you may experience these even if your medication wasn’t prescribed to treat psychosis)

It is not possible to predict if you will experience withdrawal symptoms (or how bad they will be if you do experience them). If you do experience symptoms, they are usually mild and don’t last long, but for some these could be severe enough to make you feel very unwell and last longer (two to three months or more), Arrange an appointment with your doctor to discuss your symptoms and seek advice if you are concerned or unable to tolerate them.

You can stop taking olanzapine safely with your doctor’s help. Planning a gradual withdrawal together can help to minimise or prevent the withdrawal symptoms you experience.

If you have taken more than the dose prescribed by your doctor, contact NHS 111 immediately to ask for advice, or ask a family member or friend to do this for you. This is important even if you don’t feel any different.

NHS 111 can give you advice and direct you to the best place to get more help if you need it.

If you have taken too much medication on purpose, or if after taking this you quickly feel unwell, call 999 or get someone to take you to A&E straight away. This includes any of the following signs:

• rapid beating of the heart
• agitation/aggressiveness
• problems with speech
• unusual movements (especially of the face or tongue)
• reduced level of consciousness or coma
• confusion
• seizures or fits
• a combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness, slower breathing, aspiration (breathing in vomit, mucus, or blood), high blood pressure or low blood pressure, and unusual rhythms of the heart
• a painful erection (priapism) that lasts longer than three hours

If you need to go to A&E, do not travel alone or drive yourself there. Get your parent, family member or friend to go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you and tell doctors how much you have taken.

Olanzapine can cause serious side effects, including allergic reactions.

Stop taking olanzapine and go to a hospital straight away if you get any of the following symptoms:

• difficulty breathing
• an allergic reaction or allergy (including symptoms such as swelling of your face, eyelids, lips, tongue or throat so that you cannot swallow or breathe, or really bad itching of the skin with raised lumps)
• fever, muscle stiffness, sweating or drowsiness or sleepiness (these symptoms could be caused by neuroleptic malignant syndrome)

Get your parent, family member or friend to take you or go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you.

Contact your doctor immediately but don't stop taking olanzapine, if you get any of the following symptoms:

• Increased pressure inside your eyes, which can damage your vision. This is a sign of glaucoma and symptoms include eye pain, red eyes, headache, tenderness around the eyes, blurred vision, and seeing rings around lights. An optician can check the pressure in your eye and advise you to go directly to hospital for urgent treatment if needed.
  You may not be aware you have this. Make sure you go to an optician for an eye test every two years or every year if you are 15 or younger.
• Swelling, pain, and redness in the leg, which may be from a blood clot. These clots could travel through blood vessels to the lungs causing chest pain and breathing difficulties.
• Repetitive, regular movements of the tongue, mouth and face that you’re not able to control. This condition is called ‘tardive dyskinesia’ and is extremely rare but can be very serious. It may not stop even when you stop taking the medication. If you notice it early and act with your doctor, the problem should not get worse.
• Tensing or contraction of muscles that you are not able to control. This could affect any muscle, including your eyes, mouth, tongue or jaw.
• You develop new symptoms which include needing to drink a lot, needing to pee a lot, feeling weak or feeling hungry despite having an increased appetite. These might indicate your body is not processing sugar very well.

If you receive long-acting injections, this will be administered in a clinic so you can be observed for side effects of the injection for up to three hours afterwards. This is because of a risk of ‘post-injection syndrome’. This only occurs in about two per cent of people and in less than one in every 1000 injections given. If this does occur, symptoms include feeling very sleepy, dizziness, confusion, anxiety, irritability, difficulty walking and talking, and muscle stiffness or shaking. Symptoms usually stop within one to three days. If it is going to happen, it usually occurs within three hours of the injection, but if you get these symptoms later in the day, seek urgent medical help.

If you are unable to contact your doctor, call NHS 111 for urgent advice.

Side effects are more common when you first start taking olanzapine. Many go away as you continue your medicine. If they don’t get better, or if you are worried by them and they are causing you distress, speak to your doctor or pharmacist about them.

Very common side effects of olanzapine (affecting more than one in ten people) include:

• feeling sleepy, tired, weak or exhausted
• weight gain
• increases in the levels of prolactin in the blood (may only be seen in blood tests)
• feeling dizzy or faint with a slow heart rate, especially when getting up from a lying or sitting position (this usually happens at the start of your treatment and will normally pass on its own – speak to your doctor if it doesn't)

Common side effects of olanzapine (affecting up to one in ten people) include:

• changes in the level of some blood cells, chemicals, circulating fats and, in early treatment, temporary increases in liver enzymes (seen only in blood tests)
• increased appetite
• tremor, muscle stiffness or unusual muscle movements
• dry mouth
• loss of strength or extreme tiredness
• water retention leading to swelling of the hands, ankles or feet
• joint pain
• sexual problems such as feeling less like having sex less and problems getting an erection

Olanzapine use has been linked to an increased risk of developing diabetes among some young people. Symptoms include:

• putting on weight
• needing to wee a lot
• needing to drink a lot
• feeling weak
• raised blood sugar levels

If you already have diabetes, you may need to increase the amount of medication you take for this alongside taking olanzapine.

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

This list of side effects can look scary. You may not experience any of them, but it’s important to be aware of them so you know what to do if they do happen.

Unless your side effects are very severe or distressing, try to continue taking your medication until you can talk to your doctor. Your doctor can make changes to your medication to help if needed.

You should have your weight, blood sugar, blood fats, prolactin level, blood pressure and pulse measured before you start olanzapine and regularly during early treatment, then at least every six months (if you are under 18) or once a year (if you are over 18) after that.

A blood test will be required to check your blood sugar, blood fats and prolactin level.

Your doctor might also check your heart with an electrocardiogram (ECG).

They might also check your height and development. If you have periods, they may ask if there have been any changes to the pattern or frequency of these.

It is very important to go for these checks when you are asked to do so. If you are worried or anxious about the monitoring, talk to your doctor, care team or practice nurse about this for advice and support.

You could take some of these measurements at home (e.g. weight) and keep a record of the results to share with your doctor when they review your treatment.