Sounds like 'oh-LAN-za-peen'

Easy-to-read medicine information about olanzapine – what is it, how to take olanzapine safely and possible side effects.

Type of medicine Also called
  • Antipsychotic
  • Belongs to a group of medicines known as atypical antipsychotics 
  • Olanzine®
  • Zyprexa®
  • Zypine®
Oral disintegrating tablet
  • Zyprexa Zydis®
  • Zypine ODT ® 
  • Zyprexa Relprevv® 

What is olanzapine?

  • Olanzapine is used to treat some types of mental illness such as schizophrenia and bipolar disorder (manic depression).
  • It does not cure these conditions, but will help to ease the symptoms, and to support your recovery. It works by restoring the balance of certain natural chemicals in the brain (neurotransmitters).
  • Olanzapine belongs to a group of medicines called antipsychotics.
  • Olanzapine is available in different forms of tablets, such as standard tablets, oral disintegrating tablets, and wafers.
  • It is also available as an injection. The long-acting or depot injection is an option when your symptoms have settled by taking tablets.    


  • The dose of olanzapine tablets are different for different people, depending on your condition and your response to the medication. Doses range from 5 milligrams to 20 milligrams a day.
  • Your doctor will start you on a low dose and increase it slowly as your body gets used to the medication.  
  • The dose of olanzapine depot or long-acting injection is also different for different people, depending on your condition and your response to the medication. It is usually given every 2 or every 4 weeks. 
  • Always take your olanzapine exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much olanzapine to take, how often to take it, and any special instructions.

How to take olanzapine

Olanzapine tablets

  • Olanzapine is available in different forms of tablets: 
    • Standard tablets: swallow these tablets with a glass of water. If you have problems swallowing tablets, talk to your doctor about changing to the oral disintegrating tablets, or wafers. 
    • Oral disintegrating tablets and wafers:  these tablets dissolve in your mouth. Place the tablet on your tongue and allow it to dissolve. Alternatively, you can dissolve the oral dispersible tablet by stirring into a small glassful of any of the following drinks: water, orange or apple juice, milk or coffee.
  • Olanzapine tablets are usually taken once a day. Try to take your olanzapine dose at the same time each day.
  • You can take olanzapine with or without food.
  • Limit or avoid drinking alcohol while you are taking olanzapine. Alcohol may increase your chance of side effects such as drowsiness.
  • If you forget to take your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Keep taking olanzapine every day. It usually take a few weeks to start working and it can take several months before you feel the full benefits.
  • Do not stop taking olanzapine suddenly as your symptoms may return if stopped too early; speak to your doctor or nurse before stopping.

Olanzapine long-acting (depot) injection

  • Olanzapine is also available as an injection.
  • Olanzapine depot injection is given as a shot into one of your muscles, usually your buttock (bottom).
  • This injection is given by a nurse or other trained health professional, in a clinic, community health center, or hospital.
  • The injection should change from the left buttock to the right side and back each time, so it’s not in the same place all the time.
  • As a routine, you will be observed for about 2 hours after each injection. This is because it can make you feel tired or dizzy after it is given. You will be advised not to drive or use tools or machines for the remainder of the day.


Olanzapine may cause changes in your blood sugar level, your cholesterol level and in your heart function. To keep an eye out for these effects, your doctor will monitor your physical health. You will have your weight measured regularly. You may be sent for tests such as blood tests to monitor your blood, kidneys, liver, cholesterol and glucose levels. You may also have your blood pressure measured and be required to undergo an ECG test to assess your heart rate.       

Possible side effects

Like all medicines, olanzapine can cause unwanted side effects, although not everyone gets them. Often unwanted side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sleepy, drowsy or tired
  • It can last a few hours after the dose.  
  • Don’t drive or operate machinery.  
  • Ask your doctor if you can take you medicine at a different time.
  • Avoid drinking alcohol.
  • Tell your doctor if troublesome.
  • Feeling dizzy
  • This usually only happens when you start your medication.
  • It should wear off in a few weeks.
  • Try not to stand up too quickly. You are at risk of falls.
  • If you feel dizzy, don't drive.
  • Weight gain by eating more
  • A diet full of vegetables and fibre may help prevent weight gain.
  • Limit sugary or fatty foods.
  • Speak with your doctor if your weight becomes troublesome.
  • Dry mouth
  • Suck sugar-free lollies or gum,
  • Constipation
  • Ask your doctor to prescribe a suitable laxative, which you need to take on a regular basis.
  • Eat more fruit, vegetables, brown bread, bran based breakfast cereals and drink plenty of water.
  • Signs of diabetes such as you may lose weight, pass lots of urine, and feel thirsty and hungry all the time.
  • Tell your doctor if you get these symptoms. You can then have some simple tests to see if you are developing diabetes


When certain medications are taken together, an unintended reaction may occur – this is known as an interaction. Olanzapine interacts with a number of important medications and herbal supplements so check with your doctor or pharmacist.

Learn more

The following links provide further information on olanzapine. Be aware that websites from other countries may contain information that differs from New Zealand recommendations: 

Medsafe Consumer Information (NZ)

Patient Info, UK

Credits: Sandra Ponen, Pharmacist. Reviewed By: Nicola Rowbottom, Pharmacist, South Canterbury Last reviewed: 12 Oct 2016