Dopamine D2 receptor (antagonist)

Class

Butyrophenone typical antipsychotic (dopamine D2 receptor antagonist)

Notes

Label states the effect "could be mediated through its activity as an antagonist at central dopamine type 2 receptors" — putative, label-hedged wording preserved. Sources: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8ffac6fb-1702-40d6-b085-152d24673cbd ; https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c559b0b0-4087-d12a-e718-c18ccb6811e6 (haloperidol; researched 2026-08-08)

The dopamine D2 receptor is a cell-surface protein that dopamine, a signaling molecule used by neurons, binds to activate downstream effects. It belongs to the G protein-coupled receptor family and is expressed in several brain circuits as well as in some peripheral tissues. Overactivity of dopamine signaling in certain brain pathways is associated with the positive symptoms of psychotic disorders, including hallucinations and disordered thinking. Molecules that occupy the D2 receptor without activating it act as antagonists, physically blocking dopamine from binding and thereby dampening this signaling. This is the founding mechanism of the antipsychotic drug class, and butyrophenones are one chemical family within it. Beyond psychosis, D2 antagonism is relevant to conditions marked by excessive dopaminergic drive in motor and behavioral circuits, such as Tourette syndrome and severe agitation, and to control of nausea, since a related dopamine pathway triggers vomiting. Because dopamine receptors are distributed across several distinct brain pathways with different functions, blocking them broadly can relieve target symptoms while also producing effects unrelated to the intended therapeutic goal, a trade-off that has shaped the development of this drug class over decades.