Dexmedetomidine Pharmacokinetics in the Obese

Dexmedetomidine Pharmacokinetics in the Obese

The aim of this study is to characterize, using two different modeling approaches, one based on purely statistic concept and one using a more mechanistic analysis, the influence of body weight and composition on the pharmacokinetic of dexmedetomidine.

Twenty obese patients and 20 non-obese patients scheduled for elective laparoscopic surgery will give dexmedetomidine 0.5 μg.kg-1 over 10 minutes and then randomized to either dexmedetomidine 0.25 mcg.kg-1.h-1 or dexmedetomidine 0.5 mcg.kg-1.h-1 for approximate 2 h (range 58-320 min). Blood samples will be taken at 2, 5, 10, 15, 20, 30, 45, 60, 90, 120 min after beginning dexmedetomidine administration, and at 0, 2, 5, 10, 20, 30, 60, 90, 120, 240 and 360 min after stopping infusion. Population pharmacokinetic modeling will be performed using nonlinear mixed-effects model.

Inclusion Criteria:

• American Society Anesthesiologist classification I-III patients
• between 18 and 60 years of age
• scheduled for elective laparoscopic surgery
• obese patients with a BMI >35 kg m-2 (20 patients)
• non-obese patients (BMI 18.5-25 kg m-2)(20 patients)

Exclusion Criteria:

• known allergy to study drugs
• uncontrolled hypertension
• heart block greater than first degree
• those who had taken any drug acting in the central nervous system 24 h before surgery