Pharmacology · single question
Which of the following drugs has the highest potency based on the dose-response curve?
Show answer and explanation
Correct answer: B. Drug B
Potency refers to the amount (concentration/dose) of a drug required to produce a given effect. On a dose-response curve, the MORE POTENT drug produces the same effect at a LOWER concentration — its curve is shifted to the LEFT. Drug B's curve is to the left of Drug A's, meaning Drug B achieves the same response at a lower concentration. Both drugs reach the same maximum effect (efficacy is equal), but Drug B is more potent.
- A. INCORRECT. Drug A requires a HIGHER concentration to achieve the same response as Drug B — therefore Drug A has LOWER potency. Drug A and Drug B have equal efficacy (both reach the same maximum response).
- B. CORRECT. Drug B produces the same effect at a LOWER concentration than Drug A — its curve is shifted left, indicating HIGHER potency. Potency = how much drug is needed to produce a given effect; less drug needed = more potent.