Which term is used to describe a therapeutic range where drug concentration is effective but not toxic?

The term "therapeutic window" refers to the range of drug concentrations in the body that produces the desired therapeutic effect without causing toxicity. This concept is crucial in pharmacotherapy, as it helps guide clinicians in determining dosages that maximize effectiveness while minimizing the risk of adverse effects.

A therapeutic window represents the space between the minimum effective concentration (the lowest concentration of the drug needed to achieve the desired therapeutic effect) and the minimum toxic concentration (the lowest concentration at which the drug begins to produce toxic effects). Recognizing this range is essential for safe and effective medication management, particularly for drugs that have narrow therapeutic windows, where a slight increase in dosage can lead to toxicity.

In contrast, minimum effective concentration refers solely to the lowest dose required for efficacy, and minimum toxic concentration focuses only on the dose level where toxicity starts, neither of which encompass the overall range of safe and effective dosage. Onset of action describes the time it takes for a drug to start producing its therapeutic effects, not specifically addressing the effectiveness and safety balance. Therefore, "therapeutic window" accurately captures the essential relationship between therapeutic efficacy and toxicity.