👉 Efficacy is a concept in medicine, particularly in pharmacology and clinical trials. In this context, it refers to the degree of effectiveness or efficacy of a drug in treating a particular condition. It measures how much an agent can achieve its intended effects when administered over time, taking into account factors such as dose, timing, and other variables that influence the outcome of the treatment. Efficacy is typically measured by comparing the observed therapeutic effect (e.g., symptom relief) against the expected therapeutic