Microcomputer program for interactions in drug elimination in the rat.

In modern medicine patients often require multiple drug therapy. Such therapy can be modeled by a physiological flow model using interlinked differential equations to represent the differential rates of delivery and uptake of a drug by organs. Included in the model are the sites of action, toxicity, elimination and drug binding. A menu-driven computer program for this model was developed in FORTRAN 77 for execution on a microcomputer. The program computes the rate of uptake and concentration of drug in key tissues as a function of time. Drug administration can be modeled for bolus injection with up to 10 repeats and/or for continuous infusion of the drug. The drugs warfarin and adriamycin are used as illustrative examples. The program can handle multifactorial problems such as acute and chronic competitive elimination interactions, liver damage, and features of aging such as reduced drug binding and organ function. The computed results can be printed numerically or displayed graphically, either on a screen terminal or as hard copy. The results of several simulations may be cross-plotted for studies involving parametric changes such as would occur in multiple pathology and aging.