olanzapine at a glance
Medicine class
Antipsychotic with antimanic and mood-stabilising activity
Main licensed uses
Schizophrenia, moderate-to-severe mania and prevention of bipolar recurrence after response
Food
Oral olanzapine may be taken with or without food
Available forms
Coated tablets, mouth-dissolving tablets and an acute intramuscular injection
Alertness
Sleepiness and dizziness can impair driving or machinery use
What is olanzapine used for?
The selected products are licensed for adults in the following situations:
Treatment of schizophrenia, including continuation treatment after an initial response.
Treatment of moderate-to-severe manic episodes.
Prevention of recurrence in bipolar disorder when a manic episode has responded to olanzapine.
Rapid control of agitation and disturbed behaviour associated with schizophrenia or a manic episode when oral treatment is inappropriate; this applies to the intramuscular product.
Specialist services may use oral olanzapine to manage severe nausea and vomiting caused by anticancer treatment.
How does olanzapine work?
Olanzapine blocks several brain receptors, particularly serotonin and dopamine receptors. This can reduce psychotic and manic symptoms. Effects at histamine, muscarinic and alpha-adrenergic receptors also help explain sleepiness, increased appetite, dry mouth and postural dizziness.
olanzapine preparations and strengths
Dispersible tablet
Route: Oral
Strengths: 5 mg, 10 mg, 15 mg, 20 mg
Tablet
Route: Oral
Strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg
How to take olanzapine
Take oral olanzapine exactly as prescribed and do not stop it without discussing this with the prescriber.
Swallow coated tablets with water; food does not materially affect absorption.
Place an orodispersible tablet in the mouth and allow it to disperse. Handle it carefully and use it immediately after opening the blister.
The orodispersible tablet may instead be dispersed immediately before use in water, orange juice, apple juice, milk or coffee.
The acute injection is given into a muscle by a healthcare professional. It must not be given intravenously or subcutaneously.
olanzapine side effects
Common or expected effects
- Sleepiness or fatigue
- Increased appetite and weight gain
- Dizziness, including on standing
- Constipation or dry mouth
- Restlessness or movement-related effects
- Changes in blood glucose, cholesterol or triglycerides
- Raised prolactin, which may affect periods, sexual function or breast tissue
- Rash
Get urgent medical advice
- High temperature, marked muscle stiffness, sweating or altered consciousness
- Severe allergic reaction
- New involuntary facial, tongue or body movements
- Seizure
- Symptoms of a blood clot, pulmonary embolism or stroke
- Severe hyperglycaemia, particularly with marked thirst, frequent urination, weakness or confusion
- Jaundice or other signs of significant liver injury
- Frequent infections suggesting a low white-cell count
- Prolonged painful erection
olanzapine in pregnancy
Olanzapine can be used during pregnancy when recommended after specialist assessment; untreated serious mental illness also carries risks. Weight, blood glucose and fetal growth may need closer attention. Exposure near delivery can cause temporary newborn movement, feeding, breathing, sleep or withdrawal symptoms, so maternity and neonatal teams should know about treatment. Do not stop olanzapine suddenly without medical advice.
olanzapine while breastfeeding
Oral olanzapine can be used cautiously during breastfeeding when clinically appropriate, particularly for a full-term, healthy infant, but prescriber review and infant monitoring are required. Seek advice if the baby is unusually sleepy or irritable, feeds poorly, gains weight inadequately, has abnormal movements, constipation, fewer wet nappies or a rash. Specialist advice is appropriate for premature or unwell infants or when several medicines are used.
olanzapine interactions
Tell the prescriber or pharmacist about all medicines, supplements, alcohol use and changes in smoking.
Fluvoxamine or ciprofloxacin
CYP1A2 inhibition can increase olanzapine exposure and adverse effects, requiring clinical review.
Carbamazepine
It can increase olanzapine metabolism and reduce exposure, so clinical response should be reviewed.
Tobacco smoke
Smoking can increase olanzapine clearance; starting or stopping smoking may alter exposure and warrants prescriber review.
Common questions about olanzapine
Answers are fully visible for fast scanning and source review.
How long does olanzapine take to work?
Calming or relaxation may occur earlier, but improvement in psychotic or mood symptoms can take several days or weeks.
Can olanzapine be taken with food?
Yes. Food does not materially affect oral absorption.
Does olanzapine cause weight gain?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.