Antipsychotic Drugs

Chapter 16: CNS Pharmacology:  Antipsychotics

 

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Schizophrenia

Lithium

 

 

Schizophrenia

Lateral and third ventricle enlargement: associated sulcal enlargement; cortical atrophy
"Loss of brain volume associated with schizophrenia is clearly shown by magnetic resonance imaging (MRI) scans comparing the size of ventricles (butterfly shaped, fluid-filled spaces in the midbrain) of identical twins, one of whom has schizophrenia (right).  The ventricles of the twin with schizophrenia are larger.   This suggests structural brain changes associated with the illness."- Source:  Daniel Weinberger, MD, NIMH Clinical Brain Disorders Branch--used with permission
Decreased thalamic and prefrontal cortex neuronal metabolism & altered brain metabolism (PET)

"NIMH scientist shows PET scans from a study of identical (monozygotic) twins, who are discordant for schizophrenia (only one has the disorder) demonstrating that individuals with schizophrenia have reduced brain activity in the frontal lobes (top of scan)."--http://www.nimh.nih.gov/hotsci/scanschi.htm used with permission

Positron Emission Tomography (PET)

"PET ( positron emission tomography) is a brain imaging technique that uses a radioactive tracer to show chemical activity of the brain. The PET scanner pinpoints the destination of radioactively tagged glucose, oxygen, or drugs to reveal the parts of the brain involved in performing an experimental task.

PET allows us to look at brain functions by measuring levels of energy - or activity - in specific areas of the brain. PET scans generate pictures of the working brain, providing maps of emotions, learning, vision, and memory. For example, patients may be injected with a form of radioactive glucose. The glucose winds its way to the brain through the bloodstream. Since glucose is normally the brain's fuel, the more active a part of the brain is during the task, the more glucose it uses. An array of radiation detectors in the scanner locates the radioactivity and sends the data to a computer that produces two-dimensional color-coded images (brighter colors indicate more activity) of where the brain is active. Identifying these brain functions is key in developing new ways to diagnose and treat schizophrenia and other mental disorders". Source:William Branson NIH Medical Arts

Dopamine

Antipsychotic drugs-chemical classifications

Chlorpromazine (Thorazine)

 

Thiothixene (Navane)

 

Haloperidol

 

Olanzapine (Zyprexa)

 

Risperidone (Risperdal)

 

Basic Antipsychotic Drug Pharmacology

 Adverse Effects/Reactions

Clinical Indications for Antipsychotic Drugs

Antipsychotic Drug Classes: Potencies and Toxicities

Chemical Class

Drug

Potency

Extrapyramidal Effects

Sedation

Alpha blockade: hypotension

Phenothiazine: aliphatic chlorpromazine (Thorazine)
Phenothiazine: piperazine fluphenazine (Prolixin)
Thioxanthene thiothixene (Navane)
Butyrophenone haloperidol (Haldol)
Dibenzodiazepine clozapine (Clozaril)
Thienobenzodiazepine olanzapine (Zyprexa)

--low

--very high

adapted from Table 29-1: Potter, W. Z. and Hollister, L.E.,Antipsychotic Agents and Lithium, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, p 468.

 

 

Some Antipsychotics Drug Classifications

Phenothiazines

  • chlorpromazine

  • thioridazine

  • fluphenazine

Buterophenones

  • haloperidol

Dibenzodiazepine

  • clozapine

Lithium

Lithium Pharmacology

Lithium Clinical Pharmacology

 Adverse Effects

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