Effect of Quinidine on the Pharmacokinetics and Pharmacodynamics of a CYP2D6 substrate (S-YYYY) via mixed-effect modelling

Frey, N., Laveille, C. and Jochemsen, R.

I.R.I.S. Courbevoie, France.

Objectives: The purpose of this study was to evaluate the effect of Quinidine administration on the pharmacokinetics and the pharmacodynamics (increase of the QT interval) of a compound (S-YYYY) which is mainly metabolised by the P-450 enzyme CYP2D6.

Methods: 12 healthy young volunteers were included in this study. Each volunteer participated to 2 assessment periods of one week. In each period, S-YYYY or placebo were administered according to a cross-over design. Quinidine, a selective and potent inhibitor of the P-450 enzyme CYP2D6, was administered the day before the end of each period.

Pharmacokinetic (PK) measurements: Blood samples were collected for pharmacokinetic assessment of S-YYYY with either or without Quinidine and also for pharmacokinetic assessment of Quinidine.

Pharmacodynamic (PD) measurements: QT intervals were measured at rest for Pharmacodynamic assessment of S-YYYY alone, of S-YYYY in association with Quinidine and of Quinidine alone.

PK and PK/PD analyses: Population PK and PK/PD analyses are currently implemented using the NONMEM software version 5.1. The objectives of these analyses are:

  • to investigate the influence of Quinidine on the PK parameters of S-YYYY,
  • to assess, in comparison with placebo, the PK/PD relationship between S-YYYY plasma concentrations and QT-interval duration and to assess the influence of Quinidine on this relationship.

The results of these analyses will be presented in Salamanca.

Reference: PAGE 9 () Abstr 95 [www.page-meeting.org/?abstract=95]

Poster: poster