Zacopride

Zacopride is a potent antagonist at the 5-HT₃ receptor and an agonist at the 5-HT₄ receptor. It has anxiolytic and nootropic effects in animal models, with the (R)-(+)-enantiomer being the more active form. It also has antiemetic and pro-respiratory effects, both reducing sleep apnea and reversing opioid-induced respiratory depression in animal studies. Early animal trials have also revealed that administration of zacopride can reduce preference for and consumption of ethanol.