What is it called when two drugs work together to produce an effect greater than their individual effects?

The term that describes the phenomenon where two drugs work together to produce an effect greater than the sum of their individual effects is synergism. In this context, when two substances are administered together, their combined action enhances the therapeutic effect or increases efficacy beyond what each could achieve alone. This is particularly significant in pharmacology, as it can lead to more effective treatments with lower doses of the individual drugs needed, potentially reducing side effects.

While the other options present important concepts in pharmacology, they do not accurately define the situation described. For example, antagonism refers to a scenario where one drug opposes or diminishes the effect of another drug. Potentiation indicates that one drug increases the effect of another drug, but this does not fully encompass the broader interaction that defines synergism. Interaction is a general term that can refer to any influence that one drug has on another, including both positive and negative effects, making it less specific than the defined synergistic effect.