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Brand Name(s) : Zyprexa, Zyprexa Velotab, Zypadhera
Side Effects


Olanzapine should be used with caution in:

  • People aged over 65 years
  • People with diabetes or risk factors associated with diabetes
  • Males with enlarged prostate gland (prostatic hypertrophy)
  • People with blocked intestine (paralytic ileus) and similar conditions
  • People with reduced liver or kidney function
  • People with lipid disorders or risk factors for developing lipid disorders
  • People with heart disease such as congestive heart failure or enlarged heart
  • People with blood disorders such as low blood levels of potassium (hypokalaemia) or magnesium (hypomagnesaemia) or low leucocyte or neutrophil count (neutropenia)
  • People who have had a stroke or a mini-stroke sometimes known as a TIA, or have risk factors for stroke
  • People with Parkinson's disease
  • People with dementia
  • People with abnormal heart rhythm (from an ECG scan)
  • People using medicines known to affect the electrical activity of the heart, especially the elderly
  • People with risk factors for venous thromboembolism
  • People who have or have had fits (seizures, e.g. epilepsy) or have risk factors for fits
  • People with phenylketoneuria, if taking olanzapine Velotabs as these contain aspartame which is a source of phenylalanine
  • People using other centrally acting medicines and/or alcohol

It should not be used in:

  • Anyone under the age of 18
  • Breast feeding women
  • People with or at risk of narrow-angle glaucoma (a condition where pressure inside the eye rises rapidly causing loss of vision)
  • People with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption, if taking olanzapine tablets as they contain lactose

Also see list of precautions and interactions


Stored in the original package to protect from light and moisture.


What is it used for?

  • Olanzapine is used to treat schizophrenia and manic episodes in patients with bipolar disorder.
  • It is an atypical antipsychotic, sometimes known as a neuroleptic. Atypical antipsychotics may be better tolerated than other antipsychotics with a fewer side effects of abnormal movements. Olanzapine is also an antimanic and mood stabilising agent.
  • It is used to control symptoms of agitation and disturbing behaviour associated with mania and schizophrenia. The symptoms of mania include feeling high, having excessive amounts of energy and sometimes being very irritable. Symptoms of schizophrenia include hallucinations (hearing, seeing or sensing things which are not there), abnormal thoughts (mistaken beliefs, unusual suspiciousness) and becoming withdrawn.
  • In general this drug is used to calm mood and behaviour in patients with schizophrenia or in patients with manic episodes of bipolar disorder.
  • Benefits of being on this drug can include improvements in the symptoms of schizophrenia. Olanzapine can lead to a reduction and remission of manic symptoms in patients with manic or mixed episode bipolar disorder. It also helps to prevent recurrence of symptoms.

Listed below are the typical uses of olanzapine.

  • Schizophrenia
  • Maintaining clinical improvement in patients with schizophrenia who have shown an initial response
  • Moderate to severe manic episodes in patients with bipolar disorder
  • Preventing recurrence of manic episode in patients who have responded to treatment

On occasion your doctor may prescribe this medicine to treat a condition not on the above list.


How often do I take it?

  • Zyprexa tablets (film coated tablets)
    Take this medication orally usually one tablet a day, with or without food
  • Zyprexa Velotabs (orodispersible tablets)
    Velotabs are fragile so care must be taken opening and removing the Velotab from the blister. Place the Velotab in your mouth where it will dissolve in the saliva in your mouth and can be easily swallowed. If you prefer, you can dissolve the tablet in a glass of water, orange juice, apple juice, milk or coffee before taking.

Use this medication regularly in order to get the most benefit from it.

Remember to use it at the same time each day - unless specifically told otherwise by your doctor.

It may take some weeks before the full benefit of this drug takes effect.

Certain medical conditions may require different dosage instructions as directed by your doctor.

What dose?

  • Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

  • This medication may cause drowsiness or dizziness. If you are affected, you should avoid driving or operating machinery. Consult your doctor or pharmacist for more details.

When can I stop?

  • It is important to continue taking this medication even if you feel well, unless your doctor tells you to stop. You must follow your doctors instructions for stopping this medication as the dose may need to be lowered gradually.


  • Weight gain
  • Sleepiness
  • Abnormal laboratory test results
    - Increases in blood prolactin levels
    - Increases in the levels of some fats in the blood such as cholesterol and triglycerides
    - Increases in glucose levels in the blood and urine
    - Increases in a type of white blood cell known as an eosinophil
    - Short lasting increases in liver enzymes (AST and /or ALT)
  • Increases in appetite
  • Dizziness
  • Restlessness
  • Unusual body movements (e.g. face, tongue or hands)
  • Constipation
  • Dry mouth
  • Rash
  • Weakness
  • Tiredness
  • Water retention leading to swelling of the hands, ankles or feet (oedema)
  • Feeling faint or dizzy due to a fall in blood pressure when changing position to standing or sitting up

If any of these persist or you consider them severe then inform your doctor.

Tell your doctor immediately if you develop any of the following symptoms:

  • High fever alone or in combination with stiff muscles, change in mental state, rapid breathing and rapid heart rate as these may be signs of a serious, but rare condition known as neuroleptic malignant syndrome. This arises from a reaction to antipsychotic medicines.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.


Before taking olanzapine, tell your doctor or pharmacist if you are allergic to it, or to other atypical antipsychotics, or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: have or are at risk of narrow-angle glaucoma (raised eye pressure).

Before using this medication, tell your doctor or pharmacist your medical history, especially any of the following:

  • diabetes , enlarged prostate gland (prostatic hypertrophy), blocked intestine (paralytic ileus) and similar conditions, reduced liver or kidney function, lipid disorders, heart disease, dementia or Parkinson's disease, blood disorders, stroke or a mini-stroke, abnormal heart rhythm, fits (epilepsy) or phenylketoneuria.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

  • Alcohol intake should be avoided as when taken together with olanzapine may make you feel drowsy.

The elderly: olanzapine should be used with caution in the elderly as they are more likely to experience side effects. Elderly people with other conditions such as dementia, olanzapine may experience serious side effects such as stroke, mini-stroke or death.

Pregnancy and breastfeeding - please ensure you read the detailed information below


The safety of olanzapine has not been established during pregnancy and is not recommended. Ask your doctor or pharmacist if you have any doubts or questions about this.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Olanzapine is not safe to take if you are breastfeeding

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Before using this medicine, tell your prescriber of all the medicines you are taking including prescription medicines and medicines you have bought over the counter without a prescription. Tell your prescriber if you are taking vitamins or complementary remedies such as herbal products, as these can also interact with medicines.

If you are taking more than one medicine, these may interact with each other. Your prescriber may decide to use medicines which interact with each other if the benefit outweighs the risks. In these cases, the dose of your medicines may need to be adjusted or you may be monitored more closely.

The following medicines may interact with olanzapine:

  • Medicines used to treat Parkinson's disease or dementia
  • Carbamazepine used to treat epilepsy
  • Fluvoxamine
  • Ciprofloxacin
  • Activated charcoal
  • Medicines known to change the electrical activity of the heart, such as those affecting the heart rhythm (antiarrhythmics), antihistamines (used in the treatment of allergies), antidepressants, antipsychotics(used in the treatment of mental health problems) and antimalarials

This information does not contain all possible interactions. Therefore, tell your prescriber of all the products you are using before taking this medicine.

If you have a question or want to discuss anything about your medicine, speak to your local pharmacist.


Common symptoms in overdose include a rapid heart rate, being agitated or aggressive, abnormal movements, problems with speech and reduced level of consciousness ranging from sedation to coma.

There is no specific antidote for olanzapine. Vomiting is not recommended. Standard procedures for management of overdose may be indicated, such as gastric lavage (washing of the stomach) or administration of activated charcoal.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of olanzapine or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.


Olanzapine tablets and Velotabs

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

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Source: Selected from data included with permission and copyrighted by Boots UK Limited. This copyrighted material is sourced from a licensed data provider and is not for distribution, except as may be authorised by the applicable terms of use.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgement of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse events, nor should it be construed to indicate that use of a particular medicine is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any medicine, changing any diet, or discontinuing any course of treatment.

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