An investigation of the pharmacokinetic profile of propofol ('Diprivan') after administration for induction and maintenance of anaesthesia by repeat bolus doses in patients having spinal anaesthetic block.

In 12 premedicated patients, spinal anaesthesia was established with 0.5% bupivacaine. General anaesthesia was then induced using 2.5 mg/kg propofol given over 20s, and maintained by the administration of repeated bolus doses of 1 mg/kg propofol given 3 min after induction and at intervals of 6 min thereafter. Anaesthesia was successfully induced and maintained by this technique and recovery from anaesthesia in most patients was rapid. Blood samples were collected 2 and 6 min after each dose and at recovery in order to determine the concentrations of propofol. Pharmacokinetic data were fully evaluated in 5 patients whose dosing and sampling regimen did not differ from the methods described above. Propofol blood concentrations declined rapidly between the 2 and 6 min samples, indicating rapid distribution of propofol from blood into tissues. In 3 of the 5 patients slight accumulation of propofol occurred although there was no consistent trend. There was a wide inter-individual variability in propofol concentrations on waking.