Haloperidol is well known for its high incidence of extrapyramidal side effects due to its status as a first-generation antipsychotic (typical antipsychotic). These side effects can include symptoms such as tremors, rigidity, bradykinesia, and tardive dyskinesia. The mechanism by which haloperidol produces these side effects is primarily related to its strong blockade of dopamine D2 receptors in the brain, particularly in the basal ganglia, which plays a crucial role in the coordination of movement.
In contrast, the other medications listed, such as risperidone, olanzapine, and quetiapine, although they may have some potential for extrapyramidal symptoms, are atypical antipsychotics. These agents typically have a more balanced approach to dopamine receptor blockade and also affect serotonin receptors, which reduces the risk of extrapyramidal side effects compared to first-generation antipsychotics like haloperidol. As a result, haloperidol remains a key example when discussing psychotropic agents with a high rate of extrapyramidal symptoms.