Antipsychotics: Drugs

Synonyms

Neuroleptics

Indications

Schizophrenia, bipolar mood disorder, significant irritability, and aggression

Mechanisms of Action

There has been considerable debate about the difference between the traditional antipsychotics and the so-called atypicals. Indeed, the matter is not completely settled. It is generally agreed that the traditional antipsychotics exert their beneficial and adverse effects through dopamine blockade at the dopamine D2 receptor. The traditional antipsychotic, haloperidol, is a potent blocker of dopamine. Its capacity to bind to D2 receptors is strong, and it is not easily displaced by dopamine in the brain. This affinity and persistent binding to D2 receptors in the basal ganglia probably accounts for the motor side effects described above. By contrast, clozapine (often considered the prototype atypical) has much lower affinity for D2 receptors. Across the current list of atypical antipsychotics, the affinity for D2 receptors varies. For example, risperidone...