A method for the bedside application of first-order pharmacokinetics in therapeutic management

First-order pharmacokinetics have been shown to be useful in in-dividualizing therapy for many drugs. The application and interpretation of such analyses require complex mathematical manipulations, however, and therefore kinetics are seldom used by clinicians in the management of indi-vidual patients. This report describes a practical method based on the use of a conventional, hand-held programmable calculator to derive first-order kinetic constants from serum drug level data obtained after intermittent intravenous doses of the agent and explains how to apply these data to design more optimal dosage regimens. This method will allow professionals involved in therapeutic drug monitoring to (a) apply pharmacokinetics to individualize drug therapy in selected patients and (b) conveniently test the wider applicability of first-order pharmacokinetics in drug monitoring.