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The eMC  

Last Updated 08 Jul 2015

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Clozapine 100mg tablets

Clozapine (Kloz-uh-peen) is a medicine which is used in schizophrenia.

The information in this Medicine Guide for Clozapine varies according to the condition being treated and the particular preparation used.

There are 5 preparations of Clozapine available. If Clozapine 100mg tablets is not the preparation you are looking for, please select from the drop down list below.

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Clozapine 100mg tablets

Information specific to Clozapine 100mg tablets when used in schizophrenia

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Your medicine

Clozapine is used to treat schizophrenia. Clozapine is given to people when their previous treatments for schizophrenia have not been successful or when those treatments have caused bad side-effects. Clozapine is also used in people who have Parkinson's disease who suffer with psychosis and in whom other treatment has not been successful.

In schizophrenia there is a chemical imbalance in the brain. Clozapine blocks some of the effects of this imbalance and helps to treat the symptoms of schizophrenia such as hallucinations or delusions.

Clozapine has effects on the immune system. People who take Clozapine are prone to getting infections. You will need to have regular blood tests while you are taking Clozapine to see if it is having an effect on your immune system. When you first start taking Clozapine you will have to go for a blood test every week. After a while you will probably need to have fewer blood tests. For information on having blood tests while you are taking Clozapine speak to your prescriber or a member of your medical team.

Other information about Clozapine:

  • if you do not take Clozapine for more than two days in a row you will need to start taking it at a low dose and then the dose will need to be increased gradually like when you first started treatment with Clozapine. For more information about restarting treatment with Clozapine after you have missed some doses, speak to your prescriber or a member of your medical team
  • smoking may affect the level of Clozapine in your blood. If you stop smoking while taking Clozapine you should speak to a member of your medical team as the dose of Clozapine may need to be reduced
  • if you are changing from other oral antipsychotic preparations to Clozapine, your prescriber will gradually discontinue the other antipsychotic preparation before starting with Clozapine
  • your doctor may start you on a low dose of this medicine and then increase the dose depending on how you respond to treatment. This is in order to reduce the chance of side-effects
  • this medicine should be used for at least six months

Do not share your medicine with other people. It may not be suitable for them and may harm them.

The pharmacy label on your medicine tells you how much medicine you should take. It also tells you how often you should take your medicine. This is the dose that you and your prescriber have agreed you should take. You should not change the dose of your medicine unless you are told to do so by your prescriber.

If you feel that the medicine is making you unwell or you do not think it is working, then talk to your prescriber.

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When to take your medicine

Some medicines work best if they are taken at a specific time of day. Getting the most benefit from your medicine can also be affected by what you eat, when you eat and the times at which you take other medicines.

Specific information on when to take Clozapine can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. You can also ask your doctor or pharmacist for information about when to take your medicine.

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How to take your medicine

Some medicines have specific instructions about how to take them. This is because they work better when taken correctly. These instructions can include getting the right dose and special instructions for preparing the medicine.

Specific information on how to take Clozapine can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. Alternatively, you can request information about how to take your medicine from your doctor or pharmacist.

If you are having problems taking this form of Clozapine, you should talk to your prescriber or pharmacist. They may be able to give you advice on other ways to take your medicine or other preparations that are easier for you to take.

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Taking too much of your medicine

Taking extra doses of some medicines can be harmful. In some cases even one extra dose can cause you problems. If you take extra doses of your medicine, you must get medical advice immediately. You may need a test to assess the effect of taking extra doses. This is because the effects of taking too much medicine are very complex so it is very important that you seek medical advice.

Contact your prescriber, pharmacist, specialist clinic or call 111 for advice.

Make sure you take all of your medicine containers with you if you are advised to go to hospital.

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Stopping your medicine

If you are not having any problems taking this medicine then do not stop taking it, even if you feel better, unless advised to do so by your prescriber. If, however, you find that this medicine is causing you problems then you should talk to your prescriber about your concerns.

If your medical team decides that it is best that you do not take this medicine any more, they may advise that you do not stop Clozapine abruptly. This is because, in some instances, stopping Clozapine abruptly can cause withdrawal symptoms or cause your original condition to return. In these instances, reducing the dose of Clozapine gradually over time may reduce the chances of having these problems.

If you are in any doubt, contact your prescriber, pharmacist, specialist clinic or call 111.

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Looking after your medicine

The instructions on how you should keep your medicine are on the pharmacy label. It is a good idea to keep your medicine in the original container. This will help to keep your medicine in the best condition and also allow you to check the instructions. Do not take the medicine if the packaging appears to have been tampered with or if the medicine shows any signs of damage. Make sure that the medicine is out of the sight and reach of children.

Specific information on how to look after Clozapine can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. Alternatively, you can request information about how to look after your medicine from your doctor or pharmacist.

You must not take the medicine after the expiry date shown on the packaging. If you have any unused medicine, return it to your pharmacist who will dispose of it safely.

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Whether this medicine is suitable for you

Clozapine is not suitable for everyone and some people should never use it. Other people should only use it with special care. It is important that the person prescribing this medicine knows your full medical history.

Your prescriber may only prescribe this medicine with special care or may not prescribe it at all if you:

Furthermore the prescriber may only prescribe this medicine with special care or may not prescribe it at all for someone who is under the age of 16 years or for someone who is in a coma.

As part of the process of assessing suitability to take this medicine a prescriber may also arrange tests:

  • to determine whether or not the medicine is suitable and whether it must be prescribed with extra care
  • to check that this medicine is not having any undesired effects

Over time it is possible that Clozapine can become unsuitable for some people, or they may become unsuitable for it. If at any time it appears that Clozapine has become unsuitable, it is important that the prescriber is contacted immediately.

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A medicine is only made available to the public if the clinical trials have shown that the benefits of taking the medicine outweigh the risks.

Once a medicine has been licensed, information on the medicine's effects, both intended and unintended, is continuously recorded and updated.

Some side-effects may be serious while others may only be a mild inconvenience.

Everyone's reaction to a medicine is different. It is difficult to predict which side-effects you will have from taking a particular medicine, or whether you will have any side-effects at all. The important thing is to tell your prescriber or pharmacist if you are having problems with your medicine.

Very common: More than 1 in 10 people who take Clozapine:

  • constipation - seek medical advice if you develop constipation
  • faster heart rate
  • feeling dizzy
  • feeling drowsy
  • increased salivation
  • sedation

Common: More than 1 in 100 people who take Clozapine:

  • a drop in blood pressure on standing or sitting up
  • abnormal laboratory test results
  • blood and bone marrow problems - some of these blood and bone marrow problems may cause sepsis or may be fatal. Seek immediate medical advice if you develop any signs of infection such as a fever, sore throat or flu-like symptoms
  • blurred vision
  • convulsions
  • dry mouth
  • ECG changes
  • extrapyramidal side-effects such as muscle stiffness, feeling restless or an inability to sit still
  • fainting or brief loss of consciousness
  • headaches
  • liver problems some of these liver problems may be fatal. Seek immediate medical advice if you get nausea, vomiting, appetite loss or jaundice
  • muscle twitching
  • problems controlling body temperature such as increased body temperature or changes in sweating
  • raised blood pressure
  • seizures
  • speech problems
  • tiredness
  • tremors
  • urinary incontinence
  • urinary retention
  • weight gain

Uncommon: More than 1 in 1000 people who take Clozapine:

  • neuroleptic malignant syndrome seek immediate medical advice if you have high fever

Rare: More than 1 in 10,000 people who take Clozapine:

  • confusion
  • decreased glucose tolerance - this may lead to a worsening of diabetes
  • delirium
  • diabetes
  • feeling agitated
  • heart or circulation problems - some of these heart or circulation problems may be fatal. Seek immediate medical advice if you get palpitations, fast or irregular heart rate, chest pain, tiredness, breathing difficulties or faster breathing rate
  • pancreatitis
  • pneumonia
  • respiratory tract infection - this may be fatal
  • swallowing difficulties - these may lead to the accidental inhalation of food
  • thromboembolism

Very rare: Fewer than 1 in 10,000 people who take Clozapine:

  • bowel problems - some of these bowel problems may be fatal
  • cardiac arrest
  • death
  • enlargement of the salivary glands
  • gastrointestinal problems or worsening of gastrointestinal problems - some of these gastrointestinal problems may be fatal
  • high levels of cholesterol or other lipids in the blood
  • kidney problems
  • obsessive-compulsive behaviours
  • priapism
  • respiratory arrest
  • respiratory depression
  • skin problems
  • tardive dyskinesia
  • very high blood sugar levels which may lead to ketoacidosis or coma - some of these may be fatal

The frequency of these side-effects is unknown:

If you feel unwell or if you have concerns about a side-effect, you will need to seek advice. If you feel very ill, get medical help straight away. Contact your prescriber, pharmacist, nurse or call 111.

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Taking other medicines

If you are taking more than one medicine they may interact with each other. At times your prescriber may decide to use medicines that interact, in other cases this may not be appropriate.

The decision to use medicines that interact depends on your specific circumstances. Your prescriber may decide to use medicines that interact, if it is believed that the benefits of taking the medicines together outweigh the risks. In such cases, it may be necessary to alter your dose or monitor you more closely.

Tell your prescriber the names of all the medicines that you are taking so that they can consider all possible interactions. This includes all the medicines which have been prescribed by your GP, hospital doctor, dentist, nurse, health visitor, midwife or pharmacist. You must also tell your prescriber about medicines which you have bought over the counter without prescriptions.

The following medicines may interact with Clozapine:

The following types of medicine may interact with Clozapine:

If you are taking Clozapine and one of the above medicines or types of medicines, make sure your prescriber knows about it.

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Complementary preparations and vitamins

Medicines can interact with complementary preparations and vitamins. In general, there is not much information available about interactions between medicines and complementary preparations or vitamins.

If you are planning to take or are already taking any complementary preparations and vitamins you should ask your prescriber whether there are any known interactions with Clozapine.

Your prescriber can advise whether it is appropriate for you to take combinations that are known to interact. They can also discuss with you the possible effect that the complementary preparations and vitamins may have on your condition.

If you experience any unusual effects while taking this medicine in combination with complementary preparations and vitamins, you should tell your prescriber.

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Driving and operating machinery

When taking any medicine you should be aware that it might interfere with your ability to drive or operate machinery safely.

In the case of Clozapine:

  • this medicine could affect your ability to drive or operate machinery

You must not drive or operate machinery while you are taking Clozapine.

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Medicines can interact with certain foods. In some cases, this may be harmful and your prescriber may advise you to avoid certain foods.

In the case of Clozapine:

If your diet includes any of the above, speak to your prescriber or pharmacist for further advice.

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Alcohol can interact with certain medicines.

In the case of Clozapine:

You must not drink any alcohol if you are taking this medicine.

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Family planning and pregnancy

Most medicines, in some way, can affect the development of a baby in the womb. The effect on the baby differs between medicines and also depends on the stage of pregnancy that you have reached when you take the medicine.

In the case of Clozapine:

  • you should only take this medicine during pregnancy if your doctor thinks that you need it
  • if you could become pregnant, you must use effective contraception or abstain from penetrative sex. You must contact your prescriber if you become pregnant, or think you have become pregnant while taking Clozapine
  • if you take this medicine during the late stages of pregnancy or during labour, your baby may have some problems or withdrawal symptoms from Clozapine and may need to have some monitoring after birth

You need to discuss your specific circumstances with your doctor to weigh up the overall risks and benefits of taking this medicine. You and your doctor can make a decision about whether you are going to take this medicine during pregnancy.

If the decision is that you should not have Clozapine, then you should discuss whether there is an alternative medicine that you could take during pregnancy.

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Certain medicines can pass into breast milk and may reach your baby through breast-feeding.

Women who are taking Clozapine must not breast-feed. If you wish to breast-feed you should discuss with your prescriber whether there are any other medicines you could have. You should not stop this medicine without taking advice from your doctor.

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Ingredients of your medicine

Medicines contain active ingredients. They may also contain other, additional ingredients that help ensure the stability, safety and effectiveness of the medicine. They are also added to improve the medicine's taste and appearance and to make it easier to take. Some may be used to prolong the life of the medicine.

This medicine contains clozapine.

We are unable to list all of the ingredients for your medicine here. For a full list, you should refer to the patient information leaflet that comes with this medicine. You should check that you are able to take the ingredients of your medicine, especially if you have any allergies. You should also check whether any of these ingredients are known to have side-effects.

If you are not able to take any of the ingredients in your medicine, talk to your prescriber or pharmacist to see if they can suggest an alternative medicine. If you have reacted badly to Clozapine before, do not take Clozapine. Talk to your prescriber, pharmacist or nurse as soon as possible.

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Clozapine, Version 20, last updated 08 Jul 2015