Efficacy and Potency of Dose-Response Curve. Drug A is more potent than Drug B,but both show Drug C shows same efficacy. lower potency and lower efficacy than Drug A or B. 100 50 Drug A Drug B Drug C Log drug concentration ↑ 1 foB8 O A fOr Di积gB Figure 2.7 Typical dose response curve for drugs showing differences in potency and efficacy.EDso drug dose that shows 50%of maximal response.Efficacy and Potency of Dose-Response Curve