First-generation (typical) antipsychotics act by blocking postsynaptic D2 dopamine receptors, particularly in the mesolimbic and nigrostriatal pathways, which shifts dopamine binding toward D1 receptors, raises cyclic AMP, and produces a net negative-feedback decrease in dopamine — the immediate pharmacologic effect being increased cyclic AMP rather than decreased dopamine per se. This class belongs to psychiatric pharmacology and is defined by potency-dependent adverse effect profiles: high-potency agents predominantly cause extrapyramidal symptoms (dopamine blockade in the nigrostriatal tract) while low-potency agents predominantly cause anticholinergic, antiadrenergic, and antihistaminergic effects, with both potency classes sharing risks of neuroleptic malignant syndrome, hyperprolactinemia via tuberoinfundibular pathway disruption, and QT prolongation.
First-generation (typical) antipsychotics act by blocking postsynaptic D2 dopamine receptors, particularly in the mesolimbic and nigrostriatal pathways, which shifts dopamine binding toward D1 recept…