Use of pharmacokinetic concepts to predict anesthetic drug concentrations has not had extensive use in clinical anesthetic practice to date. The multiple exponent equations needed to describe iv drug disposition have required computer capability not practical for the operating room. An algorithm is presented that allows the clinician to use information from the pharmacokinetic literature to improve accuracy of drug dosing in the operating room. Implemented on a pocket calculator, this approach does not involve complex mathematics or lengthy computations and allows the clinician to obtain a continuous prediction of the plasma anesthetic concentration during the course of the anesthetic from iv bolus or continuous infusion of anesthetic drugs.