Addition in drug combination

While studying drug synergism, one should never add the doses of drugs in combination, unless they are of the same( or similar) chemical structure. But their effects should be added instead. Dose-reponse and response-dose conversion tables were prepared based on Michaelis-Menton equation for bimolar reactions. A modification of Burgi’s formula has been presented. Criteria indicating that two drugs are acting on the same receptor system(competitive synergism) were proposed with illustrative experimental data. The author stressed that the order of drug administration exerts a great influence upon the conclusion which might be drawn from the experiments.