The method of relative drug accumulation: a simple method for illustrating the effects of different drug dosing regimens and variability in drug elimination on time courses of drug concentrations.

A simple method is presented for graphically illustrating time courses of relative drug concentrations and accumulation during multiple dosing. This method is based on the drug amount ratio and requires knowledge of only the elimination half-life and the dosing interval. It involves the use of relative drug concentrations, where a concentration of unity is assigned to the time-averaged concentration at steady state in a reference subject for the dosing regimen(s) being evaluated. Examples of application of the method of relative drug accumulation involve simulations of the effects of different multiple-dose regimens and variability in drug elimination on time courses of drug concentrations and drug accumulation.