Monday, March 27, 2017
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Olanzapine (Zyprexa)

zyprexaZyprexa is available by prescription in the United States.

Addictive Potential: Low

Emergency Room Visits Yearly: Unknown

Mandatory Minimum Sentence: Not Scheduled, Does Not Apply; Legal by Prescription

Mechanism of Action: Decreases the Neurotransmitters Dopamine, Serotonin, Histamine, Adrenaline, GABA, and Muscarine.


Olanzapine is structurally similar to clozapine, and is classified as a thienobenzodiazepine. Olanzapine has a higher affinity for 5-HT2 serotonin receptors than D2 dopamine receptors.

Like most atypical antipsychotics, compared to the older typical ones, olanzapine has a lower affinity for histamine, cholinergic muscarinic and alpha adrenergic receptors. The mode of action of olanzapine’s antipsychotic activity is unknown. It may involve antagonism at serotonin receptors. Antagonism of dopamine receptors is associated with extrapyramidal effects such as tardive dyskinesia, and with therapeutic effects. Antagonizing H1 histamine receptors causes sedation and may cause weight gain, although antagonistic actions at 5-HT2C receptors have also been implicated in weight gain.

Zyprexa has been prescribed to nearly 20 million people in 84 countries since its approval in 1996. It was the first of a newer generation of antipsychotic medications (called atypical antipsychotics) approved for the long-term treatment of schizophrenia and acute bipolar mania.

Side Effects:

As with all neuroleptic drugs, olanzapine can cause tardive dyskinesia and rare, but life-threatening, neuroleptic malignant syndrome.

Other recognized side effects may include:

  • Aggressiveness
  • akathisia inability to remain still
  • dry mouth
  • dizziness
  • irritability
  • sedation
  • insomnia
  • urinary retention
  • orthostatic hypotension
  • weight gain (90% of users experience weight gain)
  • increased appetite
  • runny nose
  • low blood pressure
  • impaired judgment, thinking, and motor skills
  • impaired spatial orientation
  • impaired responses to senses
  • seizure
  • trouble swallowing
  • dental problems and discoloration of teeth
  • missed periods
  • problems with keeping body temperature regulated
  • apathy, lack of emotion

More Info:

Zyprexa Patient Information

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