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

Int Clin Psychopharmacol. 1995 Sep;10(3):143-6. doi: 10.1097/00004850-199510030-00002.

Abstract

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

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Benzodiazepines / pharmacology
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pharmacokinetics
  • Piperazines / blood*
  • Piperazines / metabolism*
  • Serotonin Receptor Agonists / blood*
  • Serotonin Receptor Agonists / metabolism*
  • Sex Factors
  • Smoking
  • Trazodone / blood*
  • Trazodone / metabolism*

Substances

  • Piperazines
  • Serotonin Receptor Agonists
  • Benzodiazepines
  • 1-(3-chlorophenyl)piperazine
  • Trazodone