Figure 3. Simulations showing variability in peak electroencephalographic effect after an intravenous bolus dose. Two populations of 500 individuals ages 20 and 80 yr with lean body masses of 55 kg were simulated based on the NONMEM estimates of the interindividual variability in pharmacokinetic and pharmacodynamic parameters. A bolus dose that would cause 50% of the maximum EEG effect in a typical 50-yr-old was administered to all simulated individuals (upper). An age-adjusted bolus dose that would cause 50% of the maximum EEG effect in typical 20- and 80-yr-olds was administered to the two populations (lower). The bold line represents time course of the EEG effect for the typical person in each simulated population.