Pharmacology · patient case question
Two drugs are compared on a dose-response curve. The more potent drug is the one that:
Patient case: Choosing and stopping drugs
demo: Series of prescribing decisions
chief: Several patients seen in one session raise questions about antibiotic choice, analgesia and anticoagulation.
history: One patient has a spreading odontogenic infection unresponsive to five days of empirical antibiotics. Another takes rivaroxaban for atrial fibrillation. A third developed a widespread blistering rash and mucosal ulceration a week after starting a new medication.
meds: Varies by patient.
findings: Not applicable.
Show answer and explanation
Correct answer: A. Achieves the same effect at a lower dose, appearing as a leftward-shifted curve
- A. Correct. Potency is a statement about dose. The drug whose curve sits to the left produces a given effect at a lower dose, so it has a lower EC50 and is more potent. Potency alone says nothing about how good a drug is, since it can be adjusted by changing the dose.
- B. That describes efficacy, the maximum achievable effect, which is the clinically more important property. A drug can be highly potent yet have low efficacy.
- C. Duration is a pharmacokinetic property determined by metabolism and elimination, unrelated to potency.
- D. Slope reflects the number of receptors that must be occupied and cooperativity, not potency.