Dopamine D2 receptor antagonist showing selectivity over D3 and D4 receptors (Ki values are ~ 300, ~ 1600, and ~ 2800 nM for D2, D3 and D4 receptors respectively). Exhibits antipsychotic activity in vivo with no extrapyramidal side effects. 50-fold more potent than sulpiride in antagonising the effects of apomorphine in the rat.