Long-term perospirone treatment with a single dose at bedtime in schizophrenia: relevant to intermittent dopamine D2 receptor antagonism.

Perospirone, a serotonin 5-HT2A and dopamine D2 receptor antagonist, is metabolized to ID-15036 by CYP3A4 and the elimination half-life (T1/2) for the latter is longer than the former. The active metabolite ID-15036 is an 8-times weaker D2 antagonist than perospirone, although it has a high affinity for 5-HT2A receptor. In this study, we measured the plasma concentrations of perospirone and ID-15036 in the long-term stable schizophrenic patients with a single dose of perospirone at bedtime. The mean level of perospirone at 11-15 h after a last dosing was much lower (0.49 ng/ml) than that of ID-15036 (2.89 ng/ml). These results show that a long-term perospirone monotherapy with a single dose at bedtime is effective for the maintenance treatment of chronic schizophrenia and also suggest the possibility that intermittent D2 receptor blockade may be sufficient for effective relapse prevention.