Olanzapine: uses, side effects & brands

Written & medically reviewed by Dr. Sanjay Anbu, MBBS · Last reviewed 5 November 2026

Olanzapine treats schizophrenia and bipolar disorder; it can increase weight and sugar. It belongs to the Antipsychotic / mood stabiliser group. These treat serious mental-health conditions such as psychosis, bipolar disorder and severe agitation.

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Drug type — dosing is set by your doctor

Measure	Range
Drug class	Antipsychotic / mood stabiliser
Type	Prescription
Dose	Individual — ask your doctor or pharmacist

What it is used for

Schizophrenia
Bipolar disorder (mania)
Preventing relapse in bipolar disorder
Severe agitation (injection, in hospital)

Common brand names

India: Oleanz, Olimelt, Olanex
Worldwide: Zyprexa

Common side effects

Increased appetite and weight gain
Drowsiness
Raised blood sugar and cholesterol
Dizziness on standing

Before taking it — precautions

Tell your doctor about diabetes, high cholesterol, heart disease, seizures, glaucoma or prostate problems
Your doctor may check weight, blood sugar and cholesterol regularly
In elderly people with dementia it increases the risk of stroke and death; avoid alcohol

When to see a doctor urgently

High fever with stiff muscles and confusion (urgent)
Extreme thirst, frequent urination or confusion (high sugar)
Uncontrolled movements of the face, tongue or body

Not a prescription — no dose shown. The right dose of olanzapine depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.

Frequently asked questions

Why does olanzapine cause weight gain?

It increases appetite and affects how the body handles sugar and fat. A healthy diet, activity and regular checks help.

Can I stop olanzapine when I feel better?

Do not stop suddenly. Stopping can bring symptoms back; your doctor will guide any change.

Will olanzapine make me sleepy?

Drowsiness is common, especially early on. Avoid driving until you know how it affects you.

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Sources & further reading

Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.