Which term describes the point where the drug starts to exert its therapeutic effect?

The correct choice is the term that captures the moment when a drug begins to deliver its intended therapeutic impact, which is referred to as the "onset of action." This term is critical in pharmacology and clinical practice, as it helps healthcare professionals understand how quickly they can expect a drug to begin working after administration. Knowing the onset of action informs dosing schedules and helps anticipate how quickly a patient may experience relief from symptoms or therapeutic benefits.

In comparison, terms such as "time of action" might be used colloquially but do not specifically define the moment the drug starts to work. "Peak effect" refers to the maximum therapeutic effect that a drug achieves, which occurs after the onset but not at the beginning. "Duration of action" relates to how long a drug's effects last, rather than when the effects start. Understanding these distinctions is essential for effective patient care and medication management.