Estimation of kinetic parameters from a two-point determination of the drug cumulation factor.

A method is described which allows the calculation of kinetic parameters of drugs from two data points, involving a set of simple algebraic equations. This method is based on cumulation characteristics of drugs during multiple dosing. The necessary two blood samples are collected at the end of the first dosing interval and before a succeeding dose after steady state has been reached. The method is applicable for drugs which exhibit linear kinetic characteristics not subject to concentration or time-dependent phenomena. The estimates of the kinetic parameters are associated with different ranges of possible errors, with total clearance being the most reliable estimate. The potential clinical utility of this method is discussed.