Olanzapine (for nausea)
Say it: oh-LAN-zuh-peen · Brand names: Zyprexa
Olanzapine is a medicine that, in low doses, helps prevent nausea and throwing up from chemotherapy.
What it is
Olanzapine blocks several chemical messengers in the brain, including dopamine and serotonin, that can trigger nausea. It was first made for mental health conditions. Cancer doctors use low doses of it, along with other nausea medicines, because studies show it works well for chemotherapy nausea.
Often used for
- preventing nausea and throwing up from chemotherapy (a common use backed by expert guidelines, though not listed on the FDA label)
- nausea that does not go away with other medicines
- schizophrenia and bipolar disorder, which are its FDA approved uses, usually at higher doses
How you get it
It is a pill or a tablet that melts on your tongue, taken by mouth. For nausea it is often taken once a day at bedtime, starting on the day of chemotherapy and for a few days after. Your schedule may be different.
Common side effects and what helps
- Feeling sleepy. Taking it at bedtime helps. Do not drive until you know how it affects you.
- Feeling dizzy, especially when standing. Stand up slowly.
- Dry mouth. Sip water or suck on sugar free candy.
- Constipation. Drink fluids and ask your team about a stool softener.
- Bigger appetite. This is often mild with short use.
Call your care team right away if you have
- A high fever with stiff muscles, confusion, sweating, or a fast heartbeat
- Fainting, or a fall
- A rash with fever or swollen glands
- Very high blood sugar signs, like feeling very thirsty, peeing a lot, or feeling weak
- Muscle movements you cannot control, especially in the face or tongue
- Feeling so sleepy that it is hard to wake up
Before you start, tell your team
- If you have diabetes or high blood sugar
- All medicines you take, especially sleep aids, anxiety medicines, or pain medicines that make you sleepy
- If you have dementia, seizures, glaucoma, or trouble peeing
- If you have phenylketonuria. The melting tablets may contain phenylalanine.
- If you are pregnant, may become pregnant, or are breastfeeding
Good to know
- In older adults with dementia, medicines like this one raise the risk of death. Make sure your team knows if this applies to you.
- It can raise blood sugar and cholesterol, mostly with long-term use.
- Avoid alcohol while taking it. Alcohol can make you more sleepy and dizzy.
- It can make it harder for your body to cool down. Avoid getting overheated and drink fluids.
At home
- Take it at the time your team told you, often at bedtime.
- For the melting tablet, use dry hands, place it on your tongue, and let it dissolve.
- If you miss a dose, ask your team what to do.
- Store at room temperature, away from children.
Questions to ask
- How many days should I take this after chemotherapy?
- Is it safe with my other medicines?
- What should I do if I feel too sleepy?
Side effect guides
Sources
Quick answers
- What is Olanzapine (for nausea)?
- Olanzapine is a medicine that, in low doses, helps prevent nausea and throwing up from chemotherapy. Brand names: Zyprexa.
- What is Olanzapine (for nausea) used for?
- preventing nausea and throwing up from chemotherapy (a common use backed by expert guidelines, though not listed on the FDA label); nausea that does not go away with other medicines; schizophrenia and bipolar disorder, which are its FDA approved uses, usually at higher doses.
- How is Olanzapine (for nausea) given?
- It is a pill or a tablet that melts on your tongue, taken by mouth. For nausea it is often taken once a day at bedtime, starting on the day of chemotherapy and for a few days after. Your schedule may be different.
- What are the common side effects of Olanzapine (for nausea)?
- Feeling sleepy. Feeling dizzy, especially when standing. Dry mouth. Constipation. Bigger appetite.
- When should I call my care team while taking Olanzapine (for nausea)?
- A high fever with stiff muscles, confusion, sweating, or a fast heartbeat; Fainting, or a fall; A rash with fever or swollen glands; Very high blood sugar signs, like feeling very thirsty, peeing a lot, or feeling weak; Muscle movements you cannot control, especially in the face or tongue; Feeling so sleepy that it is hard to wake up.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.