title: Comparison of the pharmacokinetics of venlafaxine extended release and desvenlafaxine in extensive and poor cytochrome P450 2D6 metabolizers.
abstract: BACKGROUND
  The goal of this study was to evaluate the impact of cytochrome P450 2D6 extensive metabolizer (EM) or poor metabolizer (PM) status on the pharmacokinetics of single doses of venlafaxine extended release (ER) and desvenlafaxine (administered as desvenlafaxine succinate) in healthy adults.
  
  
  METHODS
  In an open-label, crossover study, 14 healthy volunteers (aged 18-55 years; 7 EMs and 7 PMs) received, in randomized sequence, single doses of venlafaxine ER 75 mg/d or desvenlafaxine 100 mg/d. Cytochrome P450 2D6 genotyping was performed, and plasma drug levels were measured. The arithmetic means and standard deviation (SD) for area under the plasma concentration-versus-time curve (AUC) and peak plasma concentration (Cmax) were calculated. Comparisons of AUC and Cmax between cytochrome P450 2D6 EMs and PMs were calculated using a Wilcoxon exact test.
  
  
  RESULTS
  After administration of venlafaxine ER, mean Cmax and AUC of venlafaxine were significantly greater in PMs compared with EMs, whereas mean Cmax and AUC of its metabolite, desvenlafaxine, were significantly lower for PMs than for EMs (P = 0.001, all comparisons). In contrast, mean Cmax and AUC of desvenlafaxine after administration of desvenlafaxine were comparable between EMs and PMs.
  
  
  CONCLUSIONS
  Cytochrome P450 2D6 genetic polymorphisms had no discernible impact on exposure to desvenlafaxine after desvenlafaxine administration; in contrast, compared with an EM phenotype, a PM phenotype had a significant effect on venlafaxine and desvenlafaxine plasma concentrations after venlafaxine ER administration. This reduced pharmacokinetic variability of desvenlafaxine may translate into better uniformity of response for patients receiving desvenlafaxine versus venlafaxine, but additional studies are required to test this hypothesis.
authors.affiliation: Clinical Research Institute, Wichita, KS 67211, USA. spreskorn@cri-research.net
authors.forename: Sheldon
authors.initials: S
authors.lastname: Preskorn
authors.forename: Albena
authors.initials: A
authors.lastname: Patroneva
authors.forename: Heather
authors.initials: H
authors.lastname: Silman
authors.forename: Qin
authors.initials: Q
authors.lastname: Jiang
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Isler
authors.forename: Michael E
authors.initials: ME
authors.lastname: Burczynski
authors.forename: Saeeduddin
authors.initials: S
authors.lastname: Ahmed
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Paul
authors.forename: Alice I
authors.initials: AI
authors.lastname: Nichols
mesh_terms: D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D018592:Cross-Over Studies; D003511:Cyclohexanols / Q000097:blood / Q000493:pharmacokinetics*; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics* / Q000378:metabolism*; D003692:Delayed-Action Preparations; D000069468:Desvenlafaxine Succinate; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069470:Venlafaxine Hydrochloride; D055815:Young Adult
chemical_list: D018687:Antidepressive Agents, Second-Generation; D003511:Cyclohexanols; D003692:Delayed-Action Preparations; D000069470:Venlafaxine Hydrochloride; D019389:Cytochrome P-450 CYP2D6; D000069468:Desvenlafaxine Succinate