A phenothiazine compound with anti-adrenergic (Kis = 24, 653, 163, and 391 nM for α1A, α2A, α2B, and α2C receptors, respectively) and antidopaminergic (Kd = 0.96 nM for the dopamine D2-like receptor) actions typical of antipsychotic agents; also antagonizes calmodulin and alters the calcium-binding properties of calsequestrin.