Typical antipsychotics

Typical antipsychotics, also known as first-generation antipsychotics (FGAs) or conventional antipsychotics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, or disordered thought), particularly in schizophrenia and bipolar disorder. First introduced in the 1950s, these medications have been a fundamental part of psychiatric treatment for several decades.

Overview

Typical antipsychotics work by blocking dopamine receptors in the brain, particularly the D2 receptors, which is thought to reduce psychotic symptoms. However, their use is often associated with a higher incidence of neuroleptic side effects, including extrapyramidal symptoms (EPS), tardive dyskinesia (TD), and neuroleptic malignant syndrome (NMS), compared to their successors, the atypical antipsychotics or second-generation antipsychotics.

Common Typical Antipsychotics

Some of the most commonly used typical antipsychotics include:

• Haloperidol
• Chlorpromazine
• Fluphenazine
• Perphenazine
• Thioridazine

Indications

Typical antipsychotics are primarily indicated for the treatment of:

• Schizophrenia
• Acute psychosis
• Severe agitation or bipolar mania
• Tourette syndrome, in some cases

Side Effects

The side effects of typical antipsychotics can be significant and sometimes lead to discontinuation of the medication. These include:

• Extrapyramidal symptoms (EPS) such as parkinsonism, akathisia, and dystonia
• Tardive dyskinesia (TD), a potentially irreversible condition characterized by repetitive, involuntary movements
• Neuroleptic malignant syndrome (NMS), a rare but life-threatening reaction characterized by fever, muscle rigidity, and autonomic dysfunction
• Sedation and drowsiness
• Anticholinergic effects such as dry mouth, blurred vision, and constipation
• Orthostatic hypotension and cardiac arrhythmias

Mechanism of Action

Typical antipsychotics exert their effects primarily through antagonism of D2 dopamine receptors in the brain. This blockade of dopamine receptors is associated with both their therapeutic effects and side effects. The degree of dopamine receptor blockade correlates with the efficacy of the drug in treating psychotic symptoms as well as the risk of developing extrapyramidal side effects.

Comparison with Atypical Antipsychotics

While typical antipsychotics were the first class of drugs used to treat psychosis, the introduction of atypical antipsychotics has led to a shift in prescribing practices. Atypical antipsychotics generally have a lower risk of extrapyramidal side effects and tardive dyskinesia, making them preferred in many cases. However, typical antipsychotics may still be used when patients do not respond to or cannot tolerate atypical antipsychotics.

Conclusion

Typical antipsychotics have played a significant role in the treatment of psychosis and other severe mental health conditions. Despite their potential for serious side effects, they remain an important option for certain patients, particularly those who have not benefited from other treatments. Ongoing research and clinical practice continue to refine their use to maximize benefits while minimizing risks.

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