olanzapine
Brand names: Zyprexa
Olanzapine is a medicine used to treat certain mental disorders. It helps to balance chemicals in the brain to improve mood and behavior.
Drug Pricing (NADAC)
Brand Price
$22.81/unit
Generic Price
$0.10/unit
Generic Savings
100%
Generic Available
Yes (30 manufacturers)
Pricing data from NADAC (CMS), effective December 25, 2024. Compare all drug costs →
What it does
Olanzapine is used to treat schizophrenia in adults and teens (13-17).
Common side effects
Dizziness, Weight gain, Increased appetite
Key warnings
Olanzapine can increase the risk of death in older adults with dementia-related psychosis.
How It Works
Olanzapine is an atypical antipsychotic. It works by affecting the levels of certain chemicals in your brain. These chemicals include dopamine and serotonin, which can help improve mood, thinking, and behavior.
How to Take It
Take olanzapine once a day, with or without food. Adults with schizophrenia usually start with 5 mg to 10 mg daily. The goal is usually 10 mg per day. Your doctor may change your dose as needed.
Pregnancy & Breastfeeding
If you take olanzapine during the third trimester of pregnancy, your baby may have withdrawal symptoms after birth. There is a pregnancy registry to monitor outcomes in women who take atypical antipsychotics during pregnancy. Talk to your doctor.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store olanzapine tablets at room temperature (68° to 77°F) away from light and moisture.
Side Effects (from patient reports)
Based on 47,422 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 103,356 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.
Total Reports
103,356
Death-Related Reports
12,783
Hospitalization Reports
45,342
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 7,118 |
| 2 | WEIGHT INCREASED | 6,722 |
| 3 | OFF LABEL USE | 5,716 |
| 4 | DIABETES MELLITUS | 5,388 |
| 5 | DRUG INTERACTION | 4,048 |
| 6 | TOXICITY TO VARIOUS AGENTS | 3,966 |
| 7 | SOMNOLENCE | 3,839 |
| 8 | NAUSEA | 3,829 |
| 9 | FATIGUE | 3,426 |
| 10 | ANXIETY | 3,379 |
| 11 | OVERDOSE | 3,353 |
| 12 | VOMITING | 3,130 |
| 13 | SUICIDE ATTEMPT | 3,086 |
| 14 | CONDITION AGGRAVATED | 2,850 |
| 15 | CONFUSIONAL STATE | 2,824 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Olanzapine can increase the risk of death in older adults with dementia-related psychosis. Olanzapine is not approved to treat this condition. When using olanzapine with fluoxetine, read the Symbyax label for more warnings.
Known Drug Interactions
NSAIDs, Aspirin, Warfarin): May potentiate the risk of bleeding ( 7.4 ) Drugs Tightly Bound to Plasma Proteins: May cause a shift in plasma concentrations ( 7.6 , 7.7 ) Olanzapine: When used in combination with fluoxetine, also refer to the Drug Interactions section of the package insert for Symbyax ( 7.7 ) Drugs that Prolong the QT Interval: Do not use fluoxetine with thioridazine or pimozide. Olanzapine — Fluoxetine (60 mg single dose or 60 mg daily dose for 8 days) causes a small (mean 16%) increase in the maximum concentration of olanzapine and a small (mean 16%) decrease in olanzapine ...
Mechanism: Fluoxetine can cause a small change in the amount of olanzapine that stays in your blood. This happens because fluoxetine interferes with how your body breaks down the other medication.
What to do: Your doctor may need to adjust your doses or monitor you more closely when these drugs are used together.
7.6 Neuroleptic Drugs The risk for Parkinsonism, NMS, and akathisia may be increased by concomitant use of tetrabenazine and dopamine antagonists or antipsychotics (e.g., chlorpromazine, haloperidol, olanzapine, risperidone, thioridazine, ziprasidone) [see Warnings and Precautions ( 5.4 , 5.5 , 5.6 )] .
Mechanism: Both drugs lower dopamine activity in the brain, which can cause stiff muscles, tremors, or a dangerous fever.
What to do: Your doctor should watch you closely for any new movement problems or signs of a serious reaction.
Inducers of CYP1A2 or Glucuronyl Transferase — Omeprazole and rifampin may cause an increase in olanzapine clearance.
Mechanism: Omeprazole makes the body get rid of olanzapine faster than normal. This could make the olanzapine less effective because there is not enough of it in your system.
What to do: Your doctor might need to adjust your olanzapine dose to make sure it still works for you.
Warfarin — Warfarin (20 mg single dose) did not affect olanzapine pharmacokinetics [see Drug Interactions ( 7.2 )] . Warfarin — Single doses of olanzapine did not affect the pharmacokinetics of warfarin [see Drug Interactions ( 7.1 )] .
Mechanism: These two drugs do not interfere with how the body processes or removes each other. They are generally safe to take together without changing the dose.
What to do: No specific dose changes are needed, but continue to follow your doctor's regular monitoring plan.
Diazepam: May potentiate orthostatic hypotension. ( 7.2 ) 7.1 Potential for Other Drugs to Affect Olanzapine Diazepam — The co-administration of diazepam with olanzapine potentiated the orthostatic hypotension observed with olanzapine [see Drug Interactions ( 7.2 )] . Diazepam — Olanzapine did not influence the pharmacokinetics of diazepam or its active metabolite N-desmethyldiazepam.
Mechanism: Taking these medicines together can cause a sudden drop in blood pressure when you stand up. This can lead to dizziness or fainting.
What to do: Move slowly when standing up from a sitting or lying position and report any dizziness to your healthcare provider.
Common Questions
Can I stop taking olanzapine suddenly?
Will olanzapine make me gain weight?
Can I drink alcohol while taking olanzapine?
How long does it take for olanzapine to work?
Can I take olanzapine if I have diabetes?
What should I do if I experience side effects?
Can I drive while taking olanzapine?
Is olanzapine addictive?
Can I take olanzapine with other medications?
What if I am having thoughts of harming myself?
What are the common side effects of olanzapine?
Does olanzapine interact with other medications?
What drug class is olanzapine?
Is there a generic version of olanzapine?
Is olanzapine safe during pregnancy?
Related Medications in Atypical Antipsychotic
Other drugs grouped near olanzapine — same-class peers and common alternatives.
acamprosate
Campral
Acamprosate is a medicine that can help you stay away from alcohol if you are alcohol-dependent and have already stopped drinking.
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alprazolam
Xanax
Alprazolam (Xanax) is a medication that can help you with anxiety and panic disorders.
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amitriptyline
Elavil
Amitriptyline is a medicine used to treat depression.
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amphetamine/dextroamphetamine
Adderall, Adderall XR
Adderall XR is a stimulant medicine.
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aripiprazole
Abilify
Aripiprazole (Abilify) is a medicine used to treat certain mental disorders and mood problems.
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Related Health & Safety Data
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What the FDA Data Shows for olanzapine
The FDA label for olanzapine (sold under brand names such as Zyprexa) classifies it as a prescription-only medication in the Atypical Antipsychotic class. Olanzapine is used to treat schizophrenia in adults and teens (13-17). Official labeling lists 10 commonly reported side effects, including Dizziness, Weight gain, Increased appetite.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 47,422 voluntary reports. The database also lists 26 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.10 versus $22.81 for the brand — a 100% generic savings.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: July 10, 2023
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages