How Do First Generation Antipsychotics Work?

Reviewed on 1/10/2022

How Do First Generation Antipsychotics Work?

First generation antipsychotics are medications used in the treatment of schizophrenia and psychosis. First generation antipsychotics, also known as typical or conventional antipsychotics are the initial class of drugs developed to treat psychotic disorders.

First generation antipsychotics primarily work by reducing the activity of dopamine, one of the chemicals (neurotransmitters) released in the brain by nerve cells (neurons) to transmit signals. Some of the first generation antipsychotics also have effects on other neurotransmitters such as norepinephrine and acetylcholine.

Dopamine has many functions that include pleasure sensation, mood, learning and memory, among others. Norepinephrine improves energy and attention, and acetylcholine is responsible for muscle contraction and is used in treating nervous system disorders that cause uncontrolled muscle contractions. 

First generation antipsychotics work by blocking D2 dopamine receptors, which are protein molecules on neuronal membranes that initiate excitatory action when stimulated by dopamine. The first generation antipsychotics also depress the release of hormones by the hypothalamus and pituitary gland.

One of the first generation antipsychotics, loxapine, in addition to D2 receptors, blocks the activity of serotonin 5-HT2A receptors. Serotonin is another neurotransmitter that regulates mood and behavior, blocks 5-HT2A receptors which are excitatory, reduces aggression and has a calming effect.

How Are First Generation Antipsychotics Used?

First generation antipsychotics may be administered as:

First generation antipsychotics are used to treat the following conditions:

FDA-approved:

  • Psychotic disorders
  • Schizophrenia
  • Sedation for psychosis
  • Acute agitation
  • Behavioral disorders
  • Schizophrenia and bipolar I agitation
  • Non-psychotic anxiety
  • Tourette syndrome (a nervous system disorder involving repetitive movements or unwanted sounds)
  • Nausea and vomiting

Off-label uses:

QUESTION

Schizophrenia is the most disabling mental illness. See Answer

What Are Side Effects of First Generation Antipsychotics?

Side effects of first generation antipsychotics may include the following:

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

What Are Names of Some First Generation Antipsychotic Drugs?

Generic and brand names of first generation antipsychotic drugs include:

SLIDESHOW

Schizophrenia: Symptoms, Types, Causes, Treatment See Slideshow
References
https://reference.medscape.com/drugs/antipsychotics-1st-generation

https://www.ncbi.nlm.nih.gov/books/NBK519503/

https://www.heretohelp.bc.ca/how-antidepressant-and-antipsychotic-medications-work

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