Risperidone -d6 (R 64 766-d6) is the deuterium labeled Risperidone. Risperidone is a serotonin 5-HT 2 receptor blocker, P-Glycoprotein inhibitor and potent dopamine D 2 receptor antagonist, with K i s of 4.8, 5.9 nM for 5-HT 2A and dopamine D 2 receptor, respectively.