What is olanzapine (OL)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: February 17, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Olanzapine (OL) is an atypical antipsychotic medication primarily used to treat schizophrenia and bipolar disorder.

Key Characteristics

  • The typical dosage of olanzapine ranges from 5-20 mg per day, administered orally, with a recommended initial dose of 10 mg per day for adults 1.
  • Olanzapine has been shown to be useful in the treatment of schizophrenia and bipolar mania 1.
  • It has also been hypothesized to be effective in the management of patients with treatment-resistant PTSD symptoms due to its mechanism of action as a (5-HT) 2C receptor antagonist 1.

Administration and Efficacy

  • Treatment duration varies depending on the individual's response and condition, but it is often prescribed for an extended period, typically 6-12 months or longer, to maintain therapeutic efficacy and prevent symptom relapse.
  • Olanzapine has been found to increase slow-wave sleep and reduce rapid-eye movements, which may contribute to its effectiveness in managing nightmares 1.
  • Common side effects associated with olanzapine include somnolence, postural hypotension, constipation, dizziness, fatigue, dyspepsia, and restlessness 1.

Special Considerations

  • Olanzapine should be used with caution in elderly patients due to the risk of death in patients with dementia-related psychosis and other potential side effects 1.
  • The medication may also be associated with rare but serious skin reactions, such as drug reaction with eosinophilia and systemic symptoms (DRESS) 1.

From the FDA Drug Label

ZYPREXA (olanzapine) is an atypical antipsychotic that belongs to the thienobenzodiazepine class. The chemical designation is 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b] 1, 5benzodiazepine.

Olanzapine (OL) is an atypical antipsychotic that belongs to the thienobenzodiazepine class 2, 2.

  • It is used for the treatment of schizophrenia and bipolar I disorder.
  • The chemical structure is defined by its molecular formula C17H20N4S, which corresponds to a molecular weight of 312.44.
  • Olanzapine is a yellow crystalline solid, which is practically insoluble in water.

From the Research

Definition and Classification of Olanzapine

  • Olanzapine is an atypical antipsychotic that belongs to the thienobenzodiazepine class 3
  • It is a serotonin-dopamine receptor antagonist primarily used in the treatment of psychotic illnesses, including schizophrenia and bipolar disorder 4, 5

Mechanism of Action and Efficacy

  • Olanzapine has a relatively greater binding affinity for 5-HT2 compared to D2 receptors, making it similar to the atypical agent clozapine, a serotonin/dopamine antagonist 3
  • It has been shown to be as effective as haloperidol in the acute treatment and maintenance treatment of schizophrenia, with greater efficacy in treating negative symptoms 4, 3
  • Olanzapine has also been found to be effective in the treatment of manic or mixed episodes associated with bipolar I disorder in adolescents and adults 6, 4

Metabolism and Pharmacokinetics

  • Olanzapine is metabolized by the CYP3A43 enzyme, with an intronic single nucleotide polymorphism (SNP) predicting increased olanzapine clearance 7
  • The CYP3A43 enzyme has been found to play a significant role in the metabolism of olanzapine, with molecular docking experiments and molecular dynamics simulations providing insight into the catalytic properties of the enzyme 7

Adverse Effects and Safety

  • Olanzapine has been associated with a range of adverse effects, including weight gain, sedation, extrapyramidal symptoms, and increased risk of metabolic side effects 6, 4, 5
  • The long-term medical consequences of atypical antipsychotic-induced weight gain are not yet fully understood, highlighting the need for careful consideration of risk-benefit when prescribing olanzapine 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Efficacy of olanzapine: an overview of pivotal clinical trials.

The Journal of clinical psychiatry, 1997

Research

Olanzapine: an atypical antipsychotic for schizophrenia.

Expert opinion on pharmacotherapy, 2000

Research

Metabolism of the antipsychotic drug olanzapine by CYP3A43.

Xenobiotica; the fate of foreign compounds in biological systems, 2022

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.