PHARMACOKINETICS OF PROPOFOL IN WOMEN UNDERGOING ELECTIVE CAESAREAN SECTION

We have compared the pharmacokinetics of a bolus induction dose of propofol 2 mg kg⁻¹ in 10 Chinese women undergoing elective Caesarean section with those in six non-pregnant Chinese women having laparoscopic sterilization. Blood propofol concentrations were measured using high pressure liquid chromatography with fluorimetric detection. Pharmacokinetic data were analysed by a model independent method based on statistical moment theory. Data from the laparoscopy group also underwent compartmental analysis, which produced similar kinetic results. Non-compartmental analysis estimated that the women undergoing Caesarean section had a similar elimination half-life (mean 81.27 (SD 18.87) min) and apparent volume of distribution at steady state (2.66 (0.63) litre kg⁻¹) as non-obstetric patients (99.45 (29.40) min and 3.36 (1.87) litre kg⁻¹). Clearance was more rapid in the Caesarean section group (39.32 (8.07) ml min⁻¹ kg⁻¹ vs 29.40 (8.72) ml min⁻¹ kg⁻¹) (P < 0.05). The increased total body clearance may result from blood loss and delivery of the fetus and placenta at operation, although an increase in extrahepatic clearance is also possible