Potent, selective and non-competitive mGlu₅ receptor antagonist. Acts at allosteric modulatory site (K_d values are 54 and 31 nM at rat and human mGlu₅ receptors respectively). Shows inverse agonist properties on receptor basal activity (IC₅₀ value = 84 nM). Displays analgesic, anxiolytic and antidepressant effects. Orally active.