Antipsychotics, also known as neuroleptics, are a class of medications primarily used to treat psychosis, a symptom of various mental disorders such as schizophrenia, bipolar disorder, and psychotic depression. They work by blocking certain neurotransmitter receptors in the brain, particularly dopamine receptors.
## Types of Antipsychotics
Antipsychotics are generally classified into two main types:
Typical Antipsychotics (First-Generation):
- Chlorpromazine
- Haloperidol
- Fluphenazine
- Perphenazine
- Trifluoperazine
Atypical Antipsychotics (Second-Generation):
- Aripiprazole
- Clozapine
- Olanzapine
- Quetiapine
- Risperidone
- Ziprasidone
## Mechanism of Action
Antipsychotics work by blocking neurotransmitter receptors in the brain, primarily dopamine receptors.
- Dopamine Blockade: The primary mechanism of action for antipsychotics is blocking dopamine receptors, especially in the mesolimbic and mesocortical pathways. This reduces dopaminergic activity, which is thought to be involved in the symptoms of psychosis, such as hallucinations, delusions, and disorganized thinking.
- Other Receptor Blockade: Antipsychotics may also block other neurotransmitter receptors, such as serotonin (5-HT), histamine, and muscarinic acetylcholine receptors. This can contribute to their therapeutic effects and side effects.
## Indications
Antipsychotics are primarily used to treat psychosis, which is a symptom of various mental disorders:
- Schizophrenia
- Bipolar disorder (manic and mixed episodes)
- Psychotic depression
- Tourette syndrome
- Anxiety disorders (e.g., obsessive-compulsive disorder)
- Schizoaffective disorder
## Side Effects
Antipsychotics can have a wide range of side effects, depending on the specific medication and dosage. Common side effects include:
- Typical Antipsychotics:
- Extrapyramidal symptoms (e.g., tremors, rigidity, dystonia)
- Tardive dyskinesia
- Sedation
- Orthostatic hypotension
- Atypical Antipsychotics:
- Weight gain
- Hyperglycemia
- Hyperprolactinemia
- Sedation
- Extrapyramidal symptoms (less common than with typicals)
## Considerations
- Patient Selection: Antipsychotics should be used cautiously in patients with certain medical conditions, such as cardiac arrhythmias, epilepsy, or Parkinson's disease.
- Dosing: The dose of an antipsychotic is typically individualized based on the patient's response and side effects.
- Monitoring: Patients taking antipsychotics should be monitored regularly for efficacy and side effects.
- Long-Term Use: The long-term use of antipsychotics may be associated with an increased risk of tardive dyskinesia.