Effects of gender on pharmacokinetics of propofol

Abstract

Objective To evaluate the effects of gender on the pharmacokinetics of propofol in patients.Methods Twenty ASA physical status Ⅰ or Ⅱ patients of both sexes (10 male,10 female),aged 42-59 yr,weighing 46-76 kg,scheduled for elective surgery for gastrointestinal cancer,were randomly divided into 2 gender groups (n =10 each):male group and female group.Combined intravenous-inhalational anesthesia was performed during surgery.Anesthesia was induced with iv injection of 2％ propofol 2 mg/kg,remifentanil 1.5 μg/kg,and suxamethonium chloride 1.5 mg/kg.The patients were tracheally intubated and mechanically ventilated.Anesthesia was maintained with inhalation of the mixture of 1％-2 ％ isoflurane and nitrous oxide (N2 O ∶ O2 =1 ∶ 1.),iv infusion of remifentanil 0.2-0.3 μg/kg and intermittent iv boluses of atracurium.Blood samples were taken from the central vein before propofol administration,and at 1,2,3,4,6,10,15,30,45,60,90,120,180,240,360 and 720 min after propofol administration for determination of the plasma concentration of propofol by high-performance liquid chromatography.The blood concentration-time curve of propofol was drawn and the pharmacokinetic parameters were calculated.Results The blood concentrations of propofol were significantly lower at each time points within 10 rmin after administration of the single bolus of propofol in female group than in male group (P ＜0.05).The blood concentration-time curves of propofol were fitted to a three-compartment open model in the 2 groups.The central volume of distribution and clearance rate were significantly larger in female patients than in male patients (P ＜ 0.05).Conclusion After iv injection of propofol,the blood concentration of propofol is lower,and the central volume of distribution and clearance rate are larger in female than in male,suggesting that gender has significant effect on pharmacokinetics of propofol. Key words: Sex factor; Propofol; Pharmacokinetics