The aim of this simulation study was to present a system-approach method for adjustment of continuous drug infusions at time-varying rates, aimed at achieving and then maintaining required drug concentration–time profiles in patients. The method presented can be used for safe and cost-effective individualization of drug dosing by computer-controlled infusion pumps. Utilization of this method is exemplified by simulation experiments, aimed at adjusting continuous infusions of Factor VIII (FVIII) at time-varying rates, which would theoretically yield required concentration–time profiles of FVIII in hemophilia A patients over several days.