PLASMA-CONCENTRATIONS OF TRAZODONE AND M-CHLOROPHENYLPIPERAZINE AT STEADY-STATE CAN BE PREDICTED FROM THOSE AFTER AN INITIAL DOSE OF TRAZODONE

1.The authors studied the correlations between plasma concentrations o f trazodone and mCPP at steady state and those after an initial dose o f trazodone. 2.Fifteen depressed patients received trazodone 150 mg at bedtime for 3 weeks, and blood samplings were taken 12 h after the in itial dose and 12 h after the last dose at each week. Plasma concentra tions of trazodone and mCPP were measured by high-performance liquid c hromatography. 3.Plasma concentration of mCPP, but not trazodone, was significantly higher at each week than after initial dosing. 4.For bot h trazodone and mCPP, significant linear relationships were found betw een plasma concentration after initial dosing and the average of 3 wee ks' plasma concentrations. 5.The present study thus suggests that plas ma concentrations of trazodone and mCPP at steady state can be predict ed from those after an initial dose of trazodone.