Oxatomide is a potent and orally active dual H1-histamine receptor and P2X7 receptor antagonist with antihistamine and anti-allergic activity. Oxatomide almost completely blocks the ATP-induced current in human P2X7 receptors (IC50 of 0.95 μM). Oxatomide inhibits ATP-induced Ca2+ influx with an IC50 value of 0.43 μM and also inhibits serotonin[2].