What is Olanzapine?

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For decades, a growing number of antipsychotic agents have been used for treating severe psychotic disorders.

Conventional antipsychotic drugs, such as chlorpromazine and haloperidol, have traditionally been used as first-line antipsychotic drugs for patients with schizophrenia. The introduction of clozapine in the United States in 1990 resulted in the development of what is now referred to as “atypical” or second-generation antipsychotics.

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Olanzapine is a type of second-generation antipsychotic drug that is approved for the treatment of schizophrenia and bipolar disorder. Among the newer antipsychotics, its structure and, to a lesser degree, receptor activity most closely resembles clozapine. Olanzapine was initially approved for clinical use in the European Union in 1996 and has since become one of the most commonly used antipsychotic drugs worldwide.

Clinical use and efficacy

Olanzapine shows more effectiveness in comparison to some other second-generation antipsychotic drugs. This drug is useful in the acute and maintenance treatment of schizophrenia and related disorders. Moreover, olanzapine has been shown to provide beneficial effects on both positive and negative symptoms, with a favorable side-effect profile and an early onset of antipsychotic action.

Olanzapine has also been used in the management of bipolar disorder and acute mania, either as monotherapy or in combination with lithium or valproate. Akin to other antipsychotics, it is sometimes used as an adjunct to selective serotonin reuptake inhibitors (SSRIs) in the management of obsessive-compulsive disorder (OCD) and for treatment-resistant depression.

This atypical antipsychotic was also researched as a therapeutic strategy for Gilles de la Tourette syndrome, drawing attention to its possible use for comorbid behavioral disorders. Olanzapine can effectively control tics and improve the patient's quality of life, as well as their ability to work.

Although certain studies point to olanzapine as a promising treatment for children with autistic disorder, more research is needed in order to adequately demonstrate its clinical efficacy and tolerability. This drug has also been used to treat the psychotic symptoms of Parkinson’s disease; however, its use remains controversial for this purpose, as it may aggravate parkinsonian symptoms.

Formulations of the drug

As previously mentioned, olanzapine was first introduced as an oral formulation for the treatment of schizophrenia and bipolar disorder. Recent developments have included parenteral formulations in order to improve compliance in the treatment process, as well as to address agitation in patients with schizophrenia and bipolar mania.

The olanzapine pamoate long-acting injection (depot) represents a newer formulation of the drug, which is licensed for the maintenance treatment of schizophrenia. When administered in the form of pamoate salt, olanzapine has an elimination half-life of approximately 30 days, thus allowing it to be given once every 2 or 4 weeks. By expanding the amount of time between treatment doses, this form of olanzapine consequently improves patient adherence.

Controlled release matrix pellets of olanzapine for oral use have also been developed, using a blend of sodium alginate and glyceryl palmito-stearate as matrix polymers, sodium lauryl sulphate as a pore-forming agent, and microcrystalline cellulose as a spheronizer enhancer.


Further Reading

Last Updated: Mar 22, 2021

Dr. Tomislav Meštrović

Written by

Dr. Tomislav Meštrović

Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.


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  1. Margaret Symons Margaret Symons New Zealand says:

    We realise that the purpose is to counteract psychotic behaviour. What happens when the person the medication is for only takes it for a few days then stops? Now they have reverted to previous behaviour of threatening the parent and others. I asked the parent was the adult child schizophrenic or bi polar? The parent did not know as it was confidential patient information. I'm worrying for the family. I don't know how I can help. I did say though that I thought that the strange threats etc possibly did not mean that they were in danger. Hopefully all talk and no do. But it is a worry. What do you think?

    • Lucille Costas Lucille Costas United States says:

      Schizophrenia can be a byproduct of a severe case of bi-polar behaviour when they are in the high manic state. This is sometimes referred to as "psychotic breakdown".  It does revert once the correct drugs are introduced.  However, unless they are in an extreme manic state, you probably wont see it again.  The question to ask is whether the patient is strictly bi-polar or borderline-personality disorder.  Quick difference between the two is that the bi-polar will cycle between depression and manic (low and high) very slowly - usually taking months to years.  The borderline personality can cycle rapidly, several times a day, and their manic states are usualy more severe - including complete psychotic breakdown and schizophrenia.  Read up on these and you will probably be able to recognize which disease you are relating to or dealing with.  Good luck to you.

  2. Lucille Costas Lucille Costas United States says:

    I did forget to address your issue is "threat".  To answer that simply, is YES.  Almost all bi-polars will blame and threaten those that they blame or feel anger towards - and usually will threaten them at some time.  Will they act upon those threats - that's a tossup.  Just recently a young man you was diagnosed bi-polar killed both of this parents (in the U.S.) - but I would say that it is a smaller percentage that do act on threats than those that do - at least to the point of harm or death.  However, they are very good at psychological warfare and will do their best to cause mental harm to those around them, and they do it often and with almost a pleasure about it, as they really don't understand why they are the "sick" one, so it must be "your" fault.    If you have a family member or friend that has one of these diseases, I highly urge you to run (don't walk) to your nearest social services department for your state or government, and ask for a "family support group" that you could join.  Those that have been living with this disease in their lives are the best to give you the support and answers you seek.  God bless and good luck.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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