Drug Synergy – Mechanisms and Methods of Analysis

Abstract

The term synergy is derived from the Greek syn-ergos, "working together". Synergies have been described in many settings and situations of life, including mechanics, technical systems, human social life, and many more. In all cases, synergy describes the fact that a system, i.e. the combination and interaction of two or more agents or forces is such that the combined effect is greater than the sum of their individual effects. This definition implies that there are three possible ways of such an “interaction of agents or forces”: these forces could simply add up, not affecting each other (no interaction), their combination could produce a greater than expected result (synergy), or the combination could lead to a result that is less than the sum of the individual effects. This “negative” summation is called antagonism. Interactions of biologically active agents are an important aspect of pharmacology and biomedicine. In this context, interaction describes the biological activity that results from the presence of several drugs at the same time. Such situations occur in numerous clinical situations: