A comparison of 2% and 1% formulations of propofol for the induction and maintenance of anaesthesia in surgery of moderate duration

This study, conducted in 110 patients undergoing surgery of moderate duration, compared the pharmacodynamic equivalence, efficacy and safety of 1% and 2% formulations of propofol. Anaesthesia was induced with propofol 2 mg.kg-1 given over 40 s and supplementary bolus injections of propofol were given if needed. There were no significant differences between the groups in mean induction times, total induction doses of propofol, frequency and mean duration of apnoea, fentanyl requirements or mean recovery times (times to eyes opening and to orientation). Isolated statistically significant group differences in systolic and diastolic blood pressures and heart rates during induction were not considered clinically significant. Discomfort on injection occurred in 40% and 52% of those given 1% (n = 55) and 2% (n = 55) propofol, respectively; there was no statistically significant group difference in severity. No major adverse effects were reported. This study showed that the 2% formulation has a similar safety and pharmacodynamic profile to the 1% formulation.