Question

A patient with moderate hypertension is to be treated with a diuretic drug. Drug A and drug B are two diuretics with the same mechanism of action. Drug A in a dose of 500 mg produces the same magnitude of diuresis as 5 mg of Drug B. Which of the following is true? Explain your reasoning. . A. Drug A is less efficacious than Drug B. B. Drug B is 100 times more potent than Drug A. C. Toxicity of Drug B is less than that of Drug A.

Answer 1

Ans-  Drug B is 100 times more potent than Drug A.

Potency is the amount of drug required to produce an effect of given intensity. Different drugs that bind to the same receptor and produce the same type of response will typically differ from each other in terms of their affinity (potency) or efficacy. The term potency is used as a comparative term for distinguishing which agonist has a higher affinity for a given receptor.  The drug which can produce an effect at lower drug concentrations is more potent.

Option A is wrong because Efficacy is the ability of a drug to produce a maximum response. Differences in drug efficacy are evaluated by comparing differences in maximal response at high drug doses or concentrations.