Pharmacokinetics of sufentanil in obese patients.
The pharmacokinetics of sufentanil were determined in eight obese (94.1 +/- 14 kg, mean +/- SD) and eight control patients (70.1 +/- 13 kg) anesthetized for neurosurgery. After induction of anesthesia, 4 micrograms/kg of sufentanil was administered in a single intravenous bolus. Multiple arterial samples were obtained at timed intervals over 6 h, and plasma concentrations of sufentanil were measured by radioimmunoassay. Calculation of pharmacokinetic variables from the derived compartmental models demonstrated an increased volume of distribution of sufentanil in the obese (9098 +/- 2793 mL/kg ideal body weight, mean +/- SD) when compared with a control group (5073 +/- 1673 mL/kg ideal body weight) (P less than 0.01) and a prolonged elimination half-life (208 +/- 82 min vs 135 +/- 42 min, P less than 0.05). The total volume of distribution correlated linearly with the degree of obesity, as expressed in percent ideal body weight (r = 0.67). In contrast, plasma clearance was similar in both obese and control groups (32.9 +/- 12.5 vs 26.4 +/- 5.7 mL/kg ideal body weight). The high lipid solubility of sufentanil probably explains the altered pharmacokinetics of this opioid in obese patients.
Schwartz
A E
AE
Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
Matteo
R S
RS
Ornstein
E
E
Young
W L
WL
Myers
K J
KJ
D000328:Adult; D000700:Analgesics / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D006207:Half-Life; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D011863:Radioimmunoassay; D017409:Sufentanil
D000700:Analgesics; D017409:Sufentanil; D005283:Fentanyl