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.