Olanzapine (Efficacy)

Olanzapine is in a class of medications called atypical antipsychotics, structurally similar to clozapine and having the same mechanism of action. Olanzapine binds to alpha-1, dopaminergic, histaminic H1, muscarinic and serotoninergic (type 5-HT2) receptors. Compared to the typical antipsychotics, olanzapine has more reduced cardiovascular effects and induces less hyperprolactinemia and extrapyramidal reactions. From a clinical point of view, olanzapine is effective in treating the symptoms of schizophrenia and is also used in treating acute mania with bipolar disorder, and in reducing agitation and other psychotic symptoms in dementia.

Olanzapine is an atypical neuroleptic with effects similar to other neuroleptics on is used to treat both negative and positive symptoms of schizophrenia, and is also effective for persistent positive symptoms. It is also used to prevent bipolar disorder relapses when the manic episode has responded to Olanzapine.

Olanzapine is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions) in adults and teenagers 13 years of age and older. It is also used to treat bipolar disorder (manic depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods) in adults and teenagers 13 years of age and older. Olanzapine is in a class of medications called atypical antipsychotics. It works by changing the activity of certain natural substances in the brain.


  • Zyprexa®
  • Zydis®


The extrapyramidal side effects are less intense than those of the classic antipsychotics, with sedation at the beginning of the treatment but a greater incidence of metabolic effects.

Olanzapine may cause side effects:

  • drowsiness
  • dizziness
  • akathisia (restlessness)
  • unusual behavior
  • depression
  • difficulty falling asleep or staying asleep
  • weakness
  • difficulty walking
  • constipation
  • urine retention
  • weight gain
  • dry mouth
  • pain in arms, legs, back, or joints
  • breast enlargement or discharge
  • late or missed menstrual periods
  • decreased sexual ability
  • seizures
  • changes in vision
  • swelling of the arms, hands, feet, ankles, or lower legs
  • early onset or late developing dyskinesias (unusual movements of your face or body that you cannot control)
  • sore throat, fever, chills, and other signs of infection
  • very stiff muscles
  • excess sweating
  • tachycardia (fast or irregular heartbeat)
  • rash
  • hives
  • difficulty breathing or swallowing
  • Parkinson-like symptoms
  • hyperorexia (abnormal increased appetite)
  • hyperprolactinemia (higher-than-normal blood levels of the hormone prolactin; can be reversed on suspending treatment; can cause gynecomastia, galactorrhea)
  • hyperglycemia
  • orthostatic hypotension (drop in blood pressure upon standing)
  • cardiomyopathy
  • elevated hepatic enzymes
  • photosensitivity
  • leucopenia

Gene or region studied

  • DRD3
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