On an efficacy curve, once the plateau is reached, what happens if you increase the dose?

On an efficacy curve, once the plateau is reached, what happens if you increase the dose?

• A. Not produce any additional effect
• B. Increase the efficacy
• C. Decrease the risk of toxicity
• D. Increase the slope of the curve

Answer: (A)

When a dose-response curve reaches the plateau, the system has achieved its maximal effect (Emax). Pushing the dose higher cannot produce more therapeutic effect because the receptors or downstream signaling pathways mediating the response are already fully engaged. In other words, the response is saturated. Increasing the dose beyond this point does not increase efficacy; it can, however, raise the risk of toxicity and adverse effects. So the statement that no additional effect is produced is the best description of what happens once the plateau is reached.

When a dose-response curve reaches the plateau, the system has achieved its maximal effect (Emax). Pushing the dose higher cannot produce more therapeutic effect because the receptors or downstream signaling pathways mediating the response are already fully engaged. In other words, the response is saturated. Increasing the dose beyond this point does not increase efficacy; it can, however, raise the risk of toxicity and adverse effects. So the statement that no additional effect is produced is the best description of what happens once the plateau is reached.