Olanzapine - What You Should Know

Olanzapine can significantly improve both positive and negative symptoms of schizophrenia due to its high affinity to serotonin and dopamine receptors.
Olanzapine - What You Should Know

Last update: 15 February, 2020

Olanzapine is a drug that belongs to the family of atypical antipsychotics. Doctors prescribe it for the treatment of schizophrenia, as well as for treating depressive crises associated with bipolar disorder and manic episodes.

The pharmaceutical company Eli Lilly and Company was responsible for manufacturing and distributing Olanzapine formulations. However, their patent for this medication expired in 2011. Thus, it’s now generic throughout the world.

Learning about schizophrenia

Schizophrenia is a chronic psychiatric disorder characterized by distorted thoughts, hallucinations, and even delusions. These three symptoms are clinically known as “positive” symptoms. However, a patient may also suffer what doctors refer to as “negative” symptoms. Among them:

  • Social isolation
  • Apathy
  • Decreased emotional response
A cornered man.
Schizophrenia is a psychiatric illness that manifests as distorted thoughts, hallucinations, and social isolation, among others.

As for the causes that trigger schizophrenia, some people have a predisposition for it due to a series of factors. Some of the main ones are:

  • Biochemical alterations in the brain. People with this disease usually have altered levels of dopamine and serotonin in the brain.
  • Genetic factors. The presence of this disease in a parent or other close relative increases its probability in a child.
  • Problems during pregnancy. Certain complications such as anoxia, together with certain infections and trauma during this period can affect a baby. Unfortunately, it often leads to the onset of this mental illness and other problems.

Structure and mechanism of action: how does Olanzapine work?

This antipsychotic has a chemical structure related to benzodiazepines. Specifically, it’s structurally related to quetiapine and clozapine. Its antipsychotic activity is due to its interaction with serotonin receptors. More specifically, it blocks serotonin receptors in the 5-HT2 part of the brain.

In addition, it also interacts with dopamine D1 and D2 receptors, though moderately. Also, it has an affinity towards muscarinic cholinergic receptors, alpha-adrenergic and histamine H1.

Due to all of these interactions, it can trigger some adverse effects. We’ll discuss them in more detail below. Olanzapine can significantly improve both the positive and negative symptoms of schizophrenia due to its high affinity to these receptors.

Finally, it’s worth mentioning that there’s also a prolonged action formulation of this drug.

Pharmacokinetics – how does the body process Olanzapine?

Pharmacokinetics include the processes of absorption, distribution, metabolism, and elimination that a drug undergoes once administered. In this sense, Olanzapine is rapidly absorbed after oral intake.

Once absorbed, it reaches the maximum concentrations in the plasma after 6 hours. You must keep in mind that the presence of food doesn’t affect absorption and this doesn’t happen with all medications.

A person about to take a pill.
Olanzapine has a chemical structure related to benzodiazepines. Therefore, it’s used for the treatment of schizophrenia, manic episodes, and bipolar disorder.

The bioavailability of this drug, the maximum concentration of the drug in the blood available at the time of exercising the action, isn’t very high.

A strong first-pass hepatic metabolism is the reason for this. Thus, only 40% of the administered dose reaches systemic circulation.

The metabolism, which is the set of chemical reactions that a drug undergoes in the body in order to become more soluble and thus facilitate its elimination, happens in the liver.

Once metabolized, the resulting substances, known as metabolites, may or may not trigger an effect on the body. In this case, the metabolites resulting from the chemical reactions undergone by Olanzapine have no pharmacological activity.

After metabolizing, both the metabolites and the resulting drug leave the body –  30% with the urine and approximately 55% with the feces.

Adverse reactions of Olanzapine

Finally, the most frequent adverse reactions of this drug are:

  • Weight gain
  • Drowsiness
  • Increase of prolactin levels
  • Elevation of C levels cholesterol, glucose and triglycerides
  • Dizziness
  • Orthostatic hypotension
  • Constipation
  • Acatisia and dyskinesia


Olanzapine is a widely used drug in the treatment of schizophrenia. Due to its powerful effects on the body, it’s only available with medical prescription. Therefore, you shouldn’t use it unless prescribed by your doctor. Always follow their instructions and ask them any questions you might have.

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