Pharmacokinetics of dexmedetomidine infusions for sedation of postoperative patients requiring intensive caret

Br J Anaesth. 2002 May;88(5):669-75. doi: 10.1093/bja/88.5.669.


Background: The pharmacokinetics of the alpha-2 adrenoceptor agonist dexmedetomidine were studied in 10 patients requiring postoperative sedation and mechanical ventilation in the intensive care unit (ICU), and compared with previous volunteer data.

Methods: On arrival in the ICU, sedation with dexmedetomidine was commenced with a loading dose of 2.5 microg kg(-1) h(-1) over 10 min followed by a maintenance infusion of 0.7 microg kg(-1) h(-1) into a central vein. Blood samples for measurement of plasma dexmedetomidine concentrations were taken during and after sedative infusions at predetermined intervals. Pharmacokinetic variables were estimated using non-compartmental methods. In addition, non-linear mixed effects modelling was used to obtain variable estimates not readily attainable from non-compartmental methods. Respiratory and haemodynamic data were recorded to enable correlation of any adverse events with the calculated pharmacokinetic profile.

Results: The harmonic mean distribution half-life of dexmedetomidine was 8.6 min and the harmonic mean terminal half-life was 3.14 h. Steady-state volume of distribution averaged 173 litres, clearance averaged 48.3 litres h(-1), and the mean residence time averaged 3.86 h.

Conclusions: Mean dexmedetomidine pharmacokinetic variables seen in postoperative, intensive care patients were similar to those previously found in volunteers, with the exception of the steady-state volume of distribution. A small loading dose provided effective sedation with no adverse events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic alpha-Agonists / blood*
  • Adrenergic alpha-Agonists / pharmacology
  • Adult
  • Aged
  • Aged, 80 and over
  • Conscious Sedation / methods
  • Critical Care / methods*
  • Dexmedetomidine / blood*
  • Dexmedetomidine / pharmacology
  • Female
  • Hemodynamics / drug effects
  • Humans
  • Hypnotics and Sedatives / blood*
  • Hypnotics and Sedatives / pharmacology
  • Male
  • Middle Aged
  • Postoperative Care / methods*
  • Respiration / drug effects
  • Respiration, Artificial


  • Adrenergic alpha-Agonists
  • Hypnotics and Sedatives
  • Dexmedetomidine