Clinical Applications of Pharmacokinetics and Adaptive Control

FOR the great majority of drugs, it is generally true that the more drug one takes per day, the greater is the total amount of drug in the body, the greater are the serum and tissue concentrations, the greater is the rate of excretion of the drug, and also the greater is the incidence of adverse reactions. In general, most of these things, except the incidence of adverse reactions, are linearly related to each other, and the kinetic behavior of these drugs can be regarded as that of linear pharmacokinetic systems. The "well-stirred tank" concepts found in introductory courses in calculus apply, and compartmental models of drug behavior are the ones commonly used. Many drugs have been studied in this way, including digitalis glycosides, aminoglycoside antibiotics, lidocaine, procainamide, quinidine, and theophylline, to name only a few.