Neuroleptic affinities for human brain receptors and their use in predicting adverse effects

Affinities of some antipsychotic drugs for 5 human brain receptors (dopamine D-2, muscarinic acetylcholine, histamine H1, alpha 1-adrenergic, and alpha 2-adrenergic receptors) were obtained using radioligand binding techniques. Seventeen drugs were studied at the D-2 receptor; 15 at the remaining receptors. These drugs showed marked differences in affinities at most receptors, and these differences may help explain variations in their propensities to cause certain adverse effects in patients. The clinical efficacy of all neuroleptics appears to be equal. Thus, these differences allow the clinician to choose drugs with low affinity for certain receptors and, thereby, minimize some of the adverse effects of these drugs in patients.