What is the effect called when taking two drugs results in greater than additive effects?

The effect that occurs when taking two drugs results in greater than additive effects is known as synergism. This phenomenon happens when the combined effect of two drugs is greater than the sum of their individual effects. For example, if drug A has an effect of 10 and drug B has an effect of 15 when taken separately, their individual effects would total 25. However, if taken together, they might produce an effect greater than 25, illustrating synergism.

Synergism highlights the importance of understanding drug interactions, as the enhanced effects can lead to heightened therapeutic benefits or increased risks of adverse effects. This principle is particularly relevant in clinical settings where multiple medications may be prescribed to achieve better health outcomes.

In contrast, tolerance refers to the body's diminished response to a drug over time, contraindication indicates a situation where a drug should not be used due to specific risks, and toxicology pertains to the study of the adverse effects of drugs and poisons. These concepts are related to drug use but do not specifically describe the enhanced effect seen in synergistic drug interactions.