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Effects of various factors on steady state plasma concentrations of trazodone and its active metabolite m-chlorophenylpiperazine

1995; Wolters Kluwer; Volume: 10; Issue: 3 Linguagem: Inglês

10.1097/00004850-199510030-00002

1473-5857

M. Ishida, K. Otani, Shuji Kaneko, Takayoshi Ohkubo, Takako Osanai, N. Yasui, Kazuo Mihara, H. Higuchi, K. Sugawara,

Neurotransmitter Receptor Influence on Behavior

Effects of various factors on steady state plasma concentrations of trazodone and its active metabolitem-chlorophenylpiperazine (mCPP) were studied in 43 depressed patients (19 males, 24 females) receiving trazodone 150 mg at bedtime for 1-3 weeks. Sixteen cases were smokers, and 19 cases were also receiving various benzodiazepines. The means (and ranges) of plasma concentrations of trazodone and mCPP, and the mCPP/trazodone ratio were 619 (251-1059) ng/ml, 59 (32-139) ng/ml and 0.100 (0.044-0.219), respectively. Smokers had significantly (p< 0.05) lower plasma concentrations of trazodone and higher mCPP/trazodone ratios than non-smokers. Age, sex and co-administration of benzodiazepines did not affect any plasma concentrations or the mCPP/trazodone ratio. In 11 cases where the dose was increased to 300 mg, neither plasma concentration/dose ratios nor the mCPP/trazodone ratio changed significantly. The present study thus suggests that: (1) there is a large interindividual variation in the metabolism of trazodone; (2) smoking enhances the metabolism, but age, sex and co-administration of benzodiazepines do not affect it; (3) trazodone and mCPP have linear kinetics.