Azaperone-d4 (R-1929-d4) is the deuterium labeled Azaperone (HY-B1470). Azaperone is an antagonist of dopamine D2 receptor (Dopamine D2 Receptor) and alpha-adrenergic receptor (AR). Azaperone reduces vasomotor tone, mean arterial pressure, hematocrit, hemoglobin concentration, and etorphine-induced duration, induces transient tachycardia followed by bradycardia, splenic uptake of red blood cells, and sedation, alters animal behaviors, and produces sedation with distinct onset and duration in foals. Azaperone is used for sedation and tranquilization in various animals to reduce stress and aggressive behaviors, and serves as a preanesthetic agent.