Olanzapine
Also known as: Zyprexa
What it's for
Olanzapine treats schizophrenia and bipolar disorder. It helps control symptoms like hallucinations, delusions, and mood swings by affecting brain chemicals.
Comes as: Tablets or orodispersible tablets
How to take it
- Adults: Usually 5mg to 20mg once daily.
- Take at the same time each day.
- Orodispersible tablets dissolve on your tongue.
- You can take it with or without food.
Doses here are typical. Always follow the instructions from your prescriber or on the packet — they come first.
Common side effects
- Weight gain (very common)
- Drowsiness
- Increased appetite
- Dizziness
- Constipation
The leaflet inside the packet lists all known side effects.
Important safety points
- Weight gain is common - maintain a healthy diet and exercise
- Can increase blood sugar - monitor if you have diabetes
- Causes drowsiness - be careful driving
- Do not stop suddenly
Get medical help urgently if…
- You have a high temperature, muscle stiffness, and confusion
- You have signs of diabetes (extreme thirst, passing lots of urine)
- You have thoughts of harming yourself
- You have uncontrolled muscle movements
Call NHS 111 for urgent advice, or 999 if someone is seriously unwell.
Before you act on anything here
This page is general information, written to help you understand — it is not personal medical advice and it cannot tell you what is right for you. Talk to your own GP, pharmacist or nurse about your own health.
- Need help now but it's not an emergency? Call NHS 111 or use 111.nhs.uk.
- Emergency? Call 999 or go to A&E.