Question

Potency of a drug is inversely proportional to

• A. Dose
• B. Concentration
• C. Response
• D. Formulation

Hint:

Pharmacodynamics Fundamentals:
Potency $\propto 1/\text{Dose}$ (or $1/\text{ED}_{50}$). Lower dose needed $\implies$ Higher potency.
Efficacy = Maximal response ($E_{\max}$) achievable.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Dose-response curve pharmacology: drug potency reflects the concentration or dose required to produce 50% of the maximum biological effect ($ ext{EC}_{50} / ext{ED}_{50}$).
Key Formula or Approach:
\[ \text{Potency} \propto \frac{1}{\text{ED}_{50} \text{ (Effective Dose 50)}} \]

Step 2: Detailed Explanation:
In quantitative pharmacological pharmacodynamics:
- Potency refers to the amount (dose or concentration) of a drug required to produce a biological effect of given intensity.
- It is quantitatively expressed by the median effective dose ($\text{ED}_{50}$) on a graded log dose-response curve.
- The smaller the dose or concentration required to achieve $50\%$ of maximal response ($E_{\max}$), the more potent the drug is.
- Therefore, Potency is inversely proportional to the Dose ($\text{Potency} \propto 1/\text{Dose}$).

Step 3: Final Answer:
Hence, potency of a drug is inversely proportional to Dose, corresponding to option (A).