> Western Medicines > Olanzapine


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What is Olanzapine for?

Olanzapine is a second-generation antipsychotic. It works by balancing the chemicals in your brain and hence improves your mood, mind, and behaviour. Olanzapine is therefore used to treat different mood disorders, including schizophrenia, bipolar disorder, and depression.

How to use it?

Olanzapine can be taken by mouth as conventional tablets and orodispersible tablets or by injection. For orodispersible tablets, they should be dissolved on your tongue but not swallowed whole.


A usual adult starting dose of olanzapine is 2.5 to 10 mg daily, while maintenance doses may range from 10 to 20 mg daily.


You may also be given Olanzapine intramuscularly for rapid control of agitation. For maintenance treatment, some people may prefer Zypadhera, a prolonged release injection of olanzapine, which is usually injected into your muscle every 2 to 4 weeks.

What are the side effects of Olanzapine?

Common side effects of Olanzapine include constipation, dizziness, drowsiness, dry mouth, and increased weight. Metabolic changes may also be observed including high blood pressure, high sugar levels, and high lipid levels.

Who should not take Olanzapine?

  • Anyone who has an allergy to Olanzapine or any ingredient of the formulation.

Pharmacist Tips:

  • Avoid drinking alcohol while on this medicine.
  • BMI, blood lipid and blood glucose and waist circumference should be monitored on initiation of this medication.
  • Olanzapine can induce suicidal thoughts or behaviours in patients. Family members or caregivers should pay attention.

Common dosing schedule:
Olanzapine may be taken with or without food. Take it at a convenient time to minimise missed doses.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Olanzapine may interact with:

This medication interacts with a number of drugs, please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Olanzapine in Hong Kong?

In Hong Kong, Olanzapine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Olanzapine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 10mg (Injections)
  • 5mg / 10mg / 15mg / 20mg (Orodispersible Tablets)
  • 2.5mg / 5mg / 7.5mg / 10mg (Tablets)
Drug class
Sub class
Atypical Antipsychotics
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