Olanzapine for schizophrenia, bipolar disorder, mania and agitation

This leaflet is for parents and carers about how to use this medicine in children. Our information may differ from that provided by the manufacturers, because their information usually relates to adults. Read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Do not stop giving olanzapine suddenly, as your child is likely to get withdrawal symptoms

Name of medicine

Olanzapine (oh-LAN-za-peen)

Brand names: Zalasta®, Zyprexa®, Zyprexa Velotab®

This leaflet is about the use of olanzapine for schizophrenia, bipolar disorder and mania.

Why is it important for my child to take olanzapine?

Olanzapine belongs to the group of medicines called antipsychotics. It works by changing the activity of chemicals in the brain called neurotransmitters and will affect your child’s mood and psychological behaviour

What is olanzapine available as?

Tablets:  2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg; these contain small amounts of lactose

Orodispersible tablets (Velotabs®):  5 mg, 10 mg, 15 mg, 20 mg; these may contain small amounts of aspartame and gelatin

If you have any concerns or questions, speak with your child’s doctor or pharmacist.

When should I give olanzapine

Olanzapine is usually given once each day, usually in the evening. Try to give it at about the same time each day.

How much should I give?

Your doctor will work out the amount of olanzapine (the dose) that is right for your child. The dose will be shown on the medicine label.

Your child will probably be started on a low dose. Your doctor may then increase the dose if they think this will help. 

It is important that you follow your doctor’s instructions about how much to give.

How should I give olanzapine?


  • Tablets should be swallowed whole with a glass of water, milk or juice. You should not crush the tablet. Your child should not chew the tablet.

Orodispersible tablets

Make sure your hands are dry. Take the tablet out of the blister pack and put it on your child’s tongue straight away. The tablet will dissolve rapidly. You can also dissolve the orodispersible tablet in a glass of water, fruit juice or milk. Stir it well. Your child should drink it all straight away.

When should the medicine start working?

This depends on what your child is being treated for. If your child gets hallucinations (seeing or hearing things that are not there), these should start to get better after a week or so. It may take longer than this for delusions (believing something to be real that is not) to stop. It may take 6–8 weeks before your child’s mood and behaviour seem more normal. It is important that you continue to give olanzapine during this time. Contact your doctor if you are worried.

What if my child is sick (vomits)?

If your child is sick less than 30 minutes after having a dose of olanzapine, give them the same dose again.

If your child is sick more than 30 minutes after having a dose of olanzapine, you do not need to give them another dose. Wait until the next normal dose.

What if I forget to give it?

If you remember before your child goes to bed, give them the missed dose. You do not need to wake them up, however.

You can give the missed dose in the morning, as long as this is at least 12 hours before the next dose is due. If olanzapine makes your child sleepy, it may be better not to give the missed dose in the morning.

Never give a double dose of olanzapine.

What if I give too much?

If you think you may have given your child too much olanzapine, contact your doctor or local NHS services (111 in England and Scotland; 111 or 0845 4647 in parts of Wales) or take your child to hospital. Take the medicine container or packet with you, even if it is empty. This will be useful to the doctor. Have the packet with you if you telephone for advice.

It can be dangerous to give too much olanzapine.

Are there any possible side effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side effects).

Side effects you must do something about

If your child feels faint or dizzy, or seems to be losing consciousness, has a fever (temperature above 38°C), is cold and sweaty, has a weak or rapid heart rate (they may feel as though their heart is racing or fluttering) and stiff muscles, they may be having a rare reaction to olanzapine. Contact your doctor or take your child to hospital or call an ambulance straight away.

Contact your doctor straight away if your child has any of the following:

  • muscle spasms (stiffening of the muscles), twitching in the face and body, or uncontrolled movements of the tongue or jaw, or they seem restless and cannot control their movements
  • fever, sore throat, rash or mouth ulcers.

Other side-effects you need to know about

Your child may feel sleepy or sluggish (drowsy) for a few hours after giving a dose. It is therefore best to give olanzapine to your child at bedtime.

  • If your teenager drives, they need to be aware that their reaction times may be slower while taking olanzapine and that they may feel drowsy.

  • Rarely, girls may find their periods become irregular or stop or that they have swelling, soreness or leakage from their breasts. Boys may also feel sore around the breast area. Tell your doctor about these symptoms at your next visit.

  • They may feel sleepy, tired or weak. If this is still a problem after 2 weeks, contact your doctor for advice.

  • They may get constipated (have difficulty doing a poo). Make sure they eat food that contains fibre (e.g. bran, wholemeal bread, rice, pasta, fruit and vegetables) and that they drink plenty of fluid. If this is still a problem after 2 weeks, contact your doctor for advice.


  • They may feel light-headed or dizzy when they stand up, or may faint. This is because olanzapine may lower the blood pressure. They should stand up slowly, and should lie down for a while if they feel dizzy. If this becomes a problem, contact your doctor.


  • They may be hungrier than usual (increased appetite). Encourage them to eat fruit and vegetables and low-calorie foods, rather than foods that contain a lot of calories (avoid crisps, cakes, biscuits and sweets), and to have plenty of exercise. Otherwise they may put on weight.


  • They may have a dry mouth. Eating citrus fruits (e.g. oranges) and taking sips of water may help. If this is still a problem after 2 weeks, contact your doctor for advice.

  • Your child’s skin will be more sensitive to sunlight. Keep them out of strong sun. When outdoors, they should wear a long-sleeved top, trousers and a hat and should use a high-factor sun screen (at least SPF 30).

There may sometimes be other side effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side effects to a UK safety scheme at

Can other medicines be given at the same time as olanzapine?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.

olanzapine should not be taken with some medicines that you get on prescription. It is important to tell your doctor and pharmacist about any other medicines your child is taking before starting olanzapine.

  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal and complementary medicines.

Is there anything else I need to know about this medicine?

Do not suddenly stop giving your child olanzapine, as they may get withdrawal symptoms (difficulty sleeping, tremor, anxiety, nausea, vomiting).

Generally, olanzapine should not be taken during pregnancy, particularly during the last 3 months. If your daughter thinks she might be pregnant, she should contact her doctor straight away. She should continue to take olanzapine until she has seen her doctor.

Your child should be aware that if they drink alcohol while taking olanzapine, the effects will be stronger. Ideally, they should not drink alcohol.

General advice about medicines

  • Try to give medicines at about the same times each day, to help you remember.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.
  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • Make sure that the medicines you have at home have not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

If you think someone else may have taken the medicine by accident, contact your doctor straight away.

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight.
  • It does not need to be kept in the fridge.
  • Keep the medicine in the container it came in.
  • Make sure that children cannot see or reach the medicine.

Who to contact for more information?

Your child’s doctor or pharmacist will be able to give you more information about olanzapine and about other medicines used to treat your child’s condition.

England: NHS 111

Tel 111

Scotland: NHS 24

Northern Ireland: NI Direct

Wales: NHS 111 Wales

Mind (mental health support)

0300 123 3393

Young Minds - parent helpine

Copyright disclaimer

Version [2]. © NPPG, RCPCH and WellChild, all rights reserved. Review by February 2018.

The primary source for the information in this leaflet is the British National Formulary for Children. For details on any other sources used for this leaflet, please contact us through our website,

We take great care to make sure that the information in this leaflet is correct and up-to-date. However, medicines can be used in different ways for different patients. It is important that you ask the advice of your doctor or pharmacist if you are not sure about something. This leaflet is about the use of these medicines in the UK, and may not apply to other countries. The Royal College of Paediatrics and Child Health (RCPCH), the Neonatal and Paediatric Pharmacists Group (NPPG), WellChild and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this leaflet.