Pronunciation: oh-lanz-a-peen
Generic name: olanzapine
Brand names: Zyprexa, Zyprexa Zydis, Zyprexa Intramuscular, Zyprexa Relprevv
Dosage form: oral tablets, orally disintegrating tablets, intramuscular injection, long-acting intramuscular injection (Zyprexa Relprevv)
Drug class: Atypical antipsychotics

Medically reviewed by Carmen Pope, BPharm. Last updated on Jul 24, 2024.

What is olanzapine?

Olanzapine (brand name Zyprexa) is an atypical antipsychotic that may be used to treat adults and adolescents aged 13 and older with schizophrenia or bipolar I disorder. For bipolar I disorder, it may be used:

• alone for manic or mixed episodes, or in combination with lithium or valproate
• with fluoxetine for depressive episodes in people aged 10 and older.

For treatment-resistant depression, olanzapine is used in combination with fluoxetine (Symbyax).

Olanzapine is available as oral tablets, orally disintegrating tablets, or an injection that is given into a muscle (intramuscular [IM]). The olanzapine IM preparation is only for acute agitation associated with schizophrenia and bipolar I mania in adults.

Olanzapine may work by blocking certain receptors in the brain, notably dopamine and serotonin, although the exact way it works in schizophrenia and bipolar I disorder is unknown.

Olanzapine was FDA approved on September 30, 1996, under the brand name Zyprexa. Generic olanzapine is available.

Olanzapine side effects

Olanzapine may cause serious side effects such as an increased risk of death or stroke in elderly patients with dementia, a higher risk of suicide when taken with fluoxetine, metabolic changes, tardive dyskinesia, low blood pressure, and blood cell disorders. See the warnings below for a full list of serious side effects.

Common side effects of olanzapine that affect 5% or more people who take it include postural hypotension (a drop in blood pressure when going from a lying or sitting position to standing)

• Constipation
• Weight gain and increased appetite
• Dizziness
• Personality disorder
• Restlessness
• Sedation
• Headache
• Abdominal pain
• Pain in the extremities
• Tiredness or lack of energy
• Dry mouth
• Tremor.

Other side effects may include increased salivation, speech disorder, forgetfulness, and the feeling of pins and needles in your limbs.

Teenagers experienced greater increases in prolactin, liver enzymes, and sleepiness when compared with adults.

Serious side effects and warnings

Olanzapine carries a Boxed warning for an increased risk of death in elderly patients with dementia-related psychosis.

An increased risk of death, strokes, or “mini-strokes” called transient ischemic attacks (TIAs) have been reported in elderly people taking olanzapine who are confused, have memory loss, or have lost touch with reality (dementia-related psychosis). These people should not be given olanzapine.

Olanzapine may cause the following serious side effects.

A higher risk of suicide when olanzapine is used in combination with fluoxetine for people with depression.

High blood sugar (hyperglycemia). This can happen if you have diabetes already or if you have never had diabetes. High blood sugar could lead to a build-up of acid in your blood due to ketones (ketoacidosis), coma, and death. Your doctor should do tests to check your blood sugar before you start taking olanzapine and during treatment. Call your doctor if you have any of these symptoms of high blood sugar (hyperglycemia) while taking olanzapine:

• feel very thirsty
• need to urinate more than usual
• feel very hungry
• feel weak or tired
• feel sick to your stomach
• feel confused or your breath smells fruity.

High-fat levels in your blood (increased cholesterol and triglycerides), especially in teenagers aged 13 to 17 or when used in combination with fluoxetine in children aged 10 to 17. Your healthcare provider should do blood tests to check your cholesterol and triglyceride levels before you start taking olanzapine and during treatment.

Weight gain. This is very common in people who take olanzapine, especially in teenagers aged 13 to 17, or when used in combination with fluoxetine in children aged 10 to 17. Some people gain a lot of weight. You and your doctor should check your weight regularly. Talk to your doctor about ways to control weight gain, such as eating a healthy, balanced diet, and exercising.

Neuroleptic Malignant Syndrome (NMS). This is a rare but serious side effect of antipsychotics, such as olanzapine that may be fatal. NMS can cause death and must be treated in a hospital. Call your doctor right away if you become severely ill and have symptoms such as high fever, excessive sweating, rigid muscles, confusion, changes in your breathing, heartbeat, and blood pressure.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). This is a serious drug hypersensitivity syndrome with symptoms such as an extensive rash, fever, swollen lymph nodes, liver inflammation, and blood abnormalities. Tell your doctor immediately if you experience any of these signs.

Tardive Dyskinesia.This condition causes persistent body movements that usually affect the face and tongue which you cannot control. It may not go away even if you stop taking olanzapine and may start after you stop taking olanzapine. Tell your doctor if you get any body movements that you cannot control.

Decreased blood pressure when you go from a lying or sitting position to standing. Symptoms may include dizziness, fast or slow heartbeat, or fainting.

Difficulty swallowing, which may cause food or liquid to get stuck in your lungs

Seizures. Tell your doctor if you have had a seizure before or if you have one during treatment with olanzapine

Changes in your blood cells. Your doctor will monitor your blood cell counts especially if you have a history of significantly low white blood cell counts or drug-induced leukopenia or neutropenia

Problems with control of body temperature. You could become very hot, for instance when you exercise a lot or live or holiday in a very hot area. You need to drink water to avoid dehydration. Call your doctor right away if you become severely ill and have any of these symptoms sweating too much or not at all, dry mouth, feeling very hot, feeling thirsty, or not able to produce enough urine.

May cause drowsiness and impair judgment, thinking, and motor skills. Use with caution when driving or operating machinery until you know how olanzapine affects you.

Olanzapine has not been approved for use in:

• children under 13 years of age when used to treat schizophrenia or bipolar I disorder
• children under 10 years of age when used in combination with fluoxetine for depressive episodes.

Tell your doctor about any side effect that bothers you or does not go away. These are not all the possible side effects of olanzapine. For more information, ask your doctor or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Olanzapine cost

The cost of prescription drugs varies depending on your insurance plan and which pharmacy you use. Refer to our price guide page for more information about the cost of olanzapine.

Before taking

Olanzapine may not be right for you. Before starting, tell your doctor if you have or had:

• heart problems
• seizures
• diabetes or high blood sugar levels (hyperglycemia)
• high cholesterol or triglyceride levels in your blood
• liver problems
• low or high blood pressure
• strokes or “mini-strokes” also called transient ischemic attacks (TIAs)
• Alzheimer’s disease
• narrow-angle glaucoma
• enlarged prostate in men
• bowel obstruction
• phenylketonuria, because some olanzapine disintegrating tablets may contain phenylalanine.
• breast cancer
• thoughts of suicide or hurting yourself
• any other medical condition
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Tell your doctor if you exercise a lot or live or holiday in hot places.

Pregnancy

Taking antipsychotic medication, such as olanzapine, in the last 3 months of pregnancy may cause breathing problems, feeding problems, or withdrawal symptoms in the newborn. If you get pregnant, tell your doctor right away but do not stop taking olanzapine without your doctor's advice.

Talk to your healthcare provider about registering with the National Pregnancy Registry for Atypical Antipsychotics. You can register by calling 1-866-961-2388 or go to http://womensmentalhealth.org/clinical-andresearch-programs/pregnancyregistry/ 

Breastfeeding

Olanzapine passes into your breast milk. If you are breastfeeding, tell your doctor if you notice severe drowsiness, irritability, feeding problems, tremors, or unusual muscle movements in the nursing baby. Talk to your doctor about the best way to feed your baby if you take olanzapine.

How should I take olanzapine?

Take olanzapine exactly as prescribed. Your doctor may need to change (adjust) the dosage of olanzapine until it is right for you.

• Olanzapine is usually taken once a day.
• Olanzapine can be taken with or without food.

The usual starting dosage of olanzapine for adults with:

• Schizophrenia is olanzapine 5 mg to 10 mg once a day.
• Bipolar I disorder is olanzapine 10 mg to 15 mg once a day.

Olanzapine disintegrating tablets

Olanzapine disintegrating tablets dissolve in your mouth without water.

• Before taking it, make sure that your hands are dry.
• Open the sachet and peel back the foil on the blister. Do not push the tablet through the foil.
• When you open the blister, remove the tablet and put it into your mouth.
• The tablet will disintegrate quickly in your saliva so that you can easily swallow it with or without drinking liquid.

Olanzapine IM injection

Olanzapine IM is a short-acting formulation that may be given to adults with schizophrenia or bipolar I mania if they have become agitated. 

• The usual dosage of olanzapine IM is 10 mg as a single dose.
  • Smaller dosages (5 mg or 7.5 mg) can be given if these are more appropriate.
• A maximum of 3 doses may be given if needed, 2 to 4 hours apart.
• Your doctor will monitor you for low blood pressure on standing (orthostatic hypotension) before giving you another dose. Tell your doctor if you feel faint or dizzy when you stand up.

Olanzapine: other information

You may need regular medical tests while taking olanzapine to check your cholesterol levels.

If you are diabetic, check your blood sugar levels regularly, because olanzapine can cause high blood sugar levels, even in people who are not diabetic.

Olanzapine may cause you to gain weight more easily. Be conscious of your weight and what you eat. Exercise regularly. Talk to your healthcare provider if you are putting on too much weight.

Call your healthcare provider if you do not think you are getting better or have any concerns about your condition while taking olanzapine.

• The symptoms of bipolar I disorder, treatment-resistant depression, or schizophrenia may include thoughts of suicide or of hurting yourself or others. If you have these thoughts at any time, tell your doctor or go to an emergency room right away.

What should I avoid while taking olanzapine?

Olanzapine can cause sleepiness and may affect your ability to make decisions, think clearly, or react quickly. You should not drive, operate heavy machinery, or do other dangerous activities until you know how it affects you.

Avoid drinking alcohol. Dangerous side effects could occur.

Avoid getting up too fast from sitting or lying down, or you may feel dizzy.

Avoid becoming overheated or dehydrated. Drink plenty of fluids, especially in hot weather and during exercise. It is easier to become dangerously overheated and dehydrated while you are taking olanzapine.

Avoid stopping olanzapine suddenly. You should never stop taking it without your doctor’s advice. When it comes time to stop olanzapine, it should be withdrawn slowly over several weeks under a doctor’s supervision. One survey reported at least 72% of people taking antipsychotics such as olanzapine experienced withdrawal symptoms.

Olanzapine withdrawal

Common symptoms of olanzapine withdrawal include nausea, headaches, dizziness, sleep disturbances, brain zaps, and psychological symptoms, such as anxiety, irritability, mood swings, and difficulty concentrating.

• Nearly half of people describe these symptoms as severe, especially during the early stage of withdrawal.
• The length of time withdrawal symptoms from olanzapine last varies; some report symptoms last two weeks or less, while others experience symptoms for years. This appears to correlate with the length of time people have taken the medication.
• If you want to stop taking olanzapine, talk to your healthcare provider about the best way to come off it. This may involve slowly reducing your dose, switching to another medication that might be easier to withdraw from, or taking other medications to help with your withdrawal symptoms.

What happens if I miss a dose?

If you miss a dose of olanzapine, take the missed dose as soon as you remember. If it is almost time for the next dose, just skip the missed dose and take your next dose at the regular time. Do not take two doses at the same time.

What happens if I overdose?

If you take too much olanzapine, call your doctor or poison control center at 1-800-222­-1222 right away, or get emergency treatment.

Overdose symptoms may include drowsiness, agitation, aggression, slurred speech, confusion, increased heart rate, jerky or uncontrolled muscle movements, trouble breathing, or fainting.

What other drugs will affect olanzapine?

Tell your doctor about all the medicines that you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. Olanzapine and some medicines may interact with each other and may not work as well, or cause possible serious side effects. Your doctor can tell you if it is safe to take olanzapine with your other medicines. Do not start or stop any medicine while taking olanzapine without talking to your doctor first. Especially tell your doctor if you take:

• Diazepam, lorazepam, or other benzodiazepines. This may make some side effects such as orthostatic hypotension worse
• Carbamazepine. May reduce the effect of olanzapine.
• Fluvoxamine. May increase levels of olanzapine and make side effects worse
• Fluoxetine. This may increase the risk of suicidal thoughts and behaviors
• Other medications that affect the brain, such as sedatives or sedating antihistamines. These can make side effects worse, especially when combined with alcohol
• Heart medications that lower blood pressure. Olanzapine may cause an enhanced effect
• Levodopa and dopamine Agonists. Olanzapine may counteract the effects of these drugs.

Anticholinergics (antimuscarinics), such as benztropine. Use with caution in patients with urinary retention, prostatic conditions, constipation, and some other conditions

Alcohol may also make side effects such as sleepiness and orthostatic hypotension worse.

Taking olanzapine with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

This is not a complete list of interactions. Talk to your healthcare provider or pharmacist for a full list of interactions.

Storage

Store olanzapine at room temperature, between 68°F to 77°F (20°C to 25°C), away from light. Keep it dry and away from moisture.

Keep out of the reach of children.

Olanzapine ingredients

Active: olanzapine.

Inactive: Depends on the manufacturer. Various generic manufacturers make olanzapine, such as Apotex Inc., Dr Reddys Labs Ltd, and Zydus Pharms. Eli Lilly and Company makes the brand of olanzapine called Zyprexa.

Olanzapine tablets (brand Zyprexa)

Active ingredient: olanzapine.

Inactive ingredients: carnauba wax, crospovidone, hydroxypropyl cellulose, hypromellose, lactose, magnesium stearate, microcrystalline cellulose, and other inactive ingredients.

Color coating: Titanium Dioxide, FD&C Blue No. 2 Aluminum Lake, or Synthetic Red Iron Oxide.

Olanzapine is available as olanzapine 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, and 20 mg tablets. Tablets are not scored.

Olanzapine disintegrating tablets ingredients (brand Zyprexa Zydis)

Active ingredient: olanzapine.

Inactive ingredients: gelatin, mannitol, aspartame, sodium methyl paraben, and sodium propylparaben.

Olanzapine Zydis orally disintegrating tablets are available as olanzapine 5 mg, 10 mg, 15 mg, and 20 mg tablets. Tablets are not scored.

Olanzapine IM injection ingredients (brand Zyprexa)

Active ingredient: olanzapine.

Inactive ingredients: lactose monohydrate, tartaric acid, hydrochloric acid, sodium hydroxide.

Olanzapine injection is available as an olanzapine 10 mg vial.

Who makes olanzapine?

Various generic manufacturers make olanzapine, such as Apotex Inc., Dr Reddys Labs Ltd, and Zydus Pharms.

Eli Lilly and Company makes the brand of olanzapine called Zyprexa.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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