Second-generation (atypical) antipsychotics act primarily through postsynaptic D2 dopamine receptor blockade combined with serotonin 5-HT2A receptor blockade, a dual mechanism that treats both positive and negative symptoms of schizophrenia (versus first-generation drugs, which act via D2 blockade alone and treat only positive symptoms) and produces markedly less extrapyramidal (neurologic) toxicity. This class belongs to psychiatric pharmacology and is defined pharmacodynamically by decreased D2 receptor binding (raising D1-mediated cyclic AMP signaling, which net-decreases dopamine) and by an adverse-effect profile encompassing metabolic syndrome, endocrine (hyperprolactinemia) effects via the tuberoinfundibular pathway, anti-adrenergic/anti-muscarinic/antihistaminergic ("anti-HAM") effects, rare neuroleptic malignant syndrome, and QT prolongation.
Second-generation (atypical) antipsychotics act primarily through postsynaptic D2 dopamine receptor blockade combined with serotonin 5-HT2A receptor blockade, a dual mechanism that treats both positi…