Neuroleptics (Antipsychotic Drugs)
Neuroleptics, also known as antipsychotic drugs, are medications primarily used to manage and treat symptoms of psychosis, including delusions, hallucinations, paranoia, and disordered thinking. These drugs are essential in the treatment of schizophrenia, bipolar disorder, and other psychiatric conditions.
Classification
- Typical (First-Generation) Antipsychotics:
- Haloperidol, Chlorpromazine, Fluphenazine, Perphenazine
- Atypical (Second-Generation) Antipsychotics:
- Risperidone, Olanzapine, Clozapine, Aripiprazole
Pharmacodynamics
- Typical Antipsychotics (First-Generation):
- These drugs block dopamine D2 receptors in the brain, particularly in the mesolimbic pathway, reducing psychotic symptoms.
- However, dopamine blockade in the nigrostriatal pathway can lead to extrapyramidal symptoms (EPS) such as:
- Tardive dyskinesia (involuntary movements)
- Parkinsonism (tremors, rigidity)
- Akathisia (restlessness)
- Dystonia (muscle contractions)
- Atypical Antipsychotics (Second-Generation):
- These drugs block both dopamine D2 receptors and serotonin (5-HT2A) receptors, balancing dopamine and serotonin activity in the brain.
- This mechanism reduces psychotic symptoms while also lowering the risk of EPS.
- Some atypicals (e.g., clozapine) also have effects on glutamate and histamine receptors, contributing to their efficacy in treatment-resistant schizophrenia.