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Propofol reduces the distribution and clearance of midazolam

Bart Jan Lichtenbelt1, Erik Olofsen, Albert Dahan

  • 1Department of Anesthesiology, University Medical Center, Groningen, University of Groningen, Groningen, The Netherlands.

Anesthesia and Analgesia
|May 4, 2010
PubMed
Abstract

Insights

Propofol significantly reduces midazolam distribution and clearance in a concentration-dependent manner. Heart rate also improved the pharmacokinetic model, reducing variability in midazolam

Area of Science:

  • Pharmacology
  • Clinical Pharmacology
  • Drug Interactions

Background:

  • Midazolam, a sedative, increases propofol concentrations.
  • This study investigates the reverse interaction: propofol's effect on midazolam pharmacokinetics.

Purpose of the Study:

  • To determine how propofol influences the pharmacokinetics of midazolam.
  • To quantify the concentration-dependent effects of propofol on midazolam distribution and clearance.

Main Methods:

  • Eight healthy males received midazolam infusions in a crossover study.
  • Propofol target-controlled infusions (0.6 or 1.0 microg/mL) were administered during one session.
  • Nonlinear mixed-effect models analyzed midazolam pharmacokinetics, incorporating propofol and hemodynamic variables.

Main Results:

  • Propofol (1.2 microg/mL) increased plasma midazolam concentration by 26.9%.
  • Propofol reduced midazolam's central volume of distribution and clearance rates.
  • Heart rate inclusion improved the midazolam pharmacokinetic model by reducing variability.

Conclusions:

  • Propofol exhibits a concentration-dependent reduction in midazolam distribution and clearance.
  • Incorporating heart rate as a covariate enhances midazolam pharmacokinetic modeling, primarily by decreasing intraindividual variability.

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