- Antipsychotics
- Pharmacology
Mechanism of Action of Antipsychotics
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- Revised on: 2020-08-04
Antipsychotics or neuroleptics are drugs that are used in the treatment of psychosis or mental illness. Psychoses are conditions associated with hallucinations and delusions.
These agents work by blocking receptors of neurotransmitters or chemical signals in the brain, mainly dopamine.
These drugs are the primary medical management of schizophrenia and they are also used in drug-induced psychoses.
It has shown that patients with dementia who have psychotic symptoms also respond to low dose antipsychotics.
What is the mechanism of action of antipsychotics?
The mechanism of action of antipsychotics in the nervous system is by blocking or receptors for the neurotransmitter dopamine.
Dopamine receptors can be classified into five subcategories as D1, D2, D3, D4, and D5. The subcategories D2, D3, and D4 are the ones associated with mental illness.
Typical antipsychotics also known as first-generation antipsychotics are potent antagonists or blockers of D2, D3, and D4. Due to this reason, typical antipsychotics are effective in the treatment of target symptoms. These medications are also associated with extrapyramidal side effects because of their ability to block D2 receptors.
Atypical antipsychotics also known as second-generation antipsychotics work by inhibiting the reuptake of serotonin as do some antidepressants which makes them more effective in treating the depressive aspects of schizophrenia
Two antipsychotics are available in depot form or injection which is a time-release form of medication for maintenance therapy.
The vehicle for these injections is sesame oil which makes the drug to be absorbed slowly over time. This reduces the number of injections needed to maintain the optimum dose of the drug.
Fluphenazine has 7-28 days duration of action whereas haloperidol has a longer duration of action of 4 weeks.
Once the patient's condition has been stabilized with an oral medication of these medications, an IM depot injection is given every 2 two 4 weeks as maintenance therapy.
