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Olanzapine (Zyprexa®, Zyprexa® Zydis)

Olanzapine (Zyprexa® and generic forms) belong to a group of medications called “atypical antipsychotics” or “second-generation antipsychotics.”

What is this medication used for?

Olanzapine was first developed to treat psychotic illnesses such as schizophrenia. Olanzapine is not approved by Health Canada for use in children and adolescents. However, research shows olanzapine can also help treat bipolar disorder, irritability associated with autism, anorexia nervosa and symptoms associated with mood and anxiety disorders.

When potential benefits outweigh risks, olanzapine may be prescribed “off-label.” Learn more about off-label medication use:

Tell your doctor or pharmacist if you:

  • Have allergies or bad reactions to a medication
  • Take (or plan to take) other prescription or non-prescription medications, including natural medicines. Some medications interact with olanzapine. Your doctor may adjust medication doses or monitor for side effects
  • Have a history (or family history) of kidney or liver disease, seizures, bowel obstruction, diabetes or glaucoma
  • Have a history (or family history) of heart disease, arrhythmia or “familial long QT syndrome”
  • Miss a period, are pregnant, breast-feeding or planning a pregnancy
  • Use alcohol or drugs. Taking olanzapine together with certain substances may cause a bad reaction. Learn more at

When will the medication start to work?

Olanzapine is usually prescribed to be taken regularly, but it is sometimes taken on an ‘as needed’ basis.

Some improvements may be seen within 1 to 2 weeks. It can take up to 6 weeks to see the full benefits of the medication. You (or your family members) may notice clearer thoughts, stable mood, and less agitation or intense fears. If you experience seeing, hearing or feeling things that are not there, this may also decrease or stop entirely.

It is important that you continue taking olanzapine regularly even if you are feeling well, as it can prevent symptoms from returning. Talk with your doctor if you feel olanzapine treatment has not been helpful. Your doctor may recommend switching you to a different medication.

This medication is not addictive. Do not stop taking it before talking to your doctor.

How do I take this medication?

Olanzapine is usually taken once daily in the evening or twice daily, with or without food. Usually, you will start with a low dose and slowly increase this dose over several days or weeks, based on how you tolerate it.

There are several forms of olanzapine: regular tablets, orally disintegrating tablets (Zyprexa Zydis® and generic forms), and a short-acting injection used in emergencies. Orally disintegrating tablets are very sensitive to moisture and should be handled with dry hands. They are packaged in “blister packs,” which should only be opened immediately before taking the tablet. The tablet should be placed on your tongue and will disintegrate quickly. It can be swallowed with or without water, but should not be chewed.

Possible common or serious side effects:

Side effects may be more common when starting a medication or after a dose increase. Talk to your doctor, nurse or pharmacist if any side effect concerns you.

  • Dizziness, drowsiness or headache
  • Feelings of agitation or restlessness
  • Increased appetite or weight gain
  • Stomach ache, constipation
  • Increased blood glucose or cholesterol levels
  • Fast or irregular heartbeat

Contact your doctor immediately if you experience:

  • Unexplained rash, seizure, fever or excessive sweating
  • Fainting, feeling lightheaded or difficulty with balance
  • Feelings of restlessness
  • Frequent urination accompanied by excessive thirst
  • Shaking, muscle spasm/stiffness, pain or weakness
  • Unexplained swelling and pain in one leg and/or chest pain and shortness of breath
  • Breast tenderness or swelling (males and females)
  • Unusual movements of fingers, toes, neck, lips or tongue
  • Thoughts of hurting yourself, suicide, increased hostility or worsening symptoms

What precautions should my doctor and I be aware of when taking this medication?

  • When you take this medication, your body may have difficulty maintaining a normal body temperature. Drink enough fluids to avoid becoming dehydrated. Avoid doing a lot of physical activity on hot days.
  • While taking this medication, if you feel dizzy, drowsy or slowed down, do not drive a car or operate heavy machinery. Alcohol could make this worse. Try to avoid alcohol while taking olanzapine.
  • Olanzapine can cause a rare side effect called “tardive dyskinesia.” Symptoms include involuntary movements of the lips, tongue, toes, hands or neck. Stopping or switching this medication at first signs will decrease the chances this side effect will continue. These movements may become permanent without a medication change.
  • Olanzapine can cause a rare side effect called “neuroleptic malignant syndrome.” Symptoms include severe muscle stiffness, high fever, sweating, increased or irregular heartbeat and increased blood pressure.
  • Olanzapine levels can be affected by smoking cigarettes. Let your doctor know if you start or stop smoking, or change your smoking habits while taking olanzapine.

How does this medication work?

Like other antipsychotics, olanzapine affects actions of the brain chemicals dopamine and serotonin. The exact way that olanzapine improve symptoms of schizophrenia, bipolar disorder and other conditions is not known.

What special instructions should I follow while using this medication?

  • Keep all appointments with your doctor and the lab. Your doctor may order lab tests to check how you are responding and monitor for side effects.
  • Try to keep a healthy, well-balanced diet and exercise regularly. Some people may gain weight as a result of increased appetite.
  • Do not allow anyone else to use your medication.

What should I do if I forget to take a dose of this medication?

If you take olanzapine only at bedtime and you forget to take a dose, skip the missed dose and continue regularly with your next scheduled dose.

If you take olanzapine more than once a day, take the missed dose as soon as you remember. However, if it is within 4 hours of your next scheduled dose, skip the missed dose and continue with your regular schedule. DO NOT double your next dose to try to ‘catch up’.

How do I store this medication?

Keep this medication in the original container, stored at room temperature away from moisture and heat and protected from light. Keep this medication out of reach and sight of children.

How well does the medication work in children and adolescents?

Evidence supports the use of olanzapine in children and adolescents. It has shown to be better than placebo (an inactive pill) for treatment of bipolar depression when used with fluoxetine and bipolar mania in ages 10 and older, as well as schizophrenia in ages 13 and older.

Limited evidence suggests that olanzapine is better than placebo for treatment of irritability of autism and symptoms associated with anxiety disorders. Olanzapine has shown to be no better than placebo for treatment of anorexia nervosa in children and adolescents. Olanzapine is sometimes prescribed for children and adolescents when other treatments have not been effective or well-tolerated.

How long should I take the medication for?

This depends on the symptoms you have, how frequently they occur, and how long you have had them. Most people will need to take olanzapine for several months. This allows time for symptoms to stabilize and for function to improve. Your doctor will discuss the benefits and risks of taking olanzapine with you. At this time, you can also discuss how long you might need to take this medication.

If you have schizophrenia and you tolerate olanzapine well, you may be asked to take olanzapine on an ongoing basis. Continuing treatment will significantly decrease the chance that your symptoms will return. Do not increase, decrease, or stop taking this medication without talking with your doctor. If you stop taking olanzapine suddenly, it is possible that your symptoms may return or you may have a bad reaction.

TIP: Use the Kelty Mental Health Antipsychotic Monitoring Form for Children and Adolescents to help measure your progress on this medication.

Also see the Kelty Mental Health document Atypical Antipsychotics & Metabolic Monitoring.

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