Which term describes reduced response to a drug after repeated exposure?

• A. Adulteration
• B. Tolerance
• C. Potentiation
• D. Stimulant

Answer: (B)

Tolerance is a diminished response to a drug after repeated exposure. When a drug is used repeatedly, the body adapts—receptors may be downregulated or desensitized, and metabolic processes can become more efficient—so the same dose yields a smaller effect. Over time, a higher dose may be needed to achieve the same level of response. This concept helps explain why some medications seem to lose their effectiveness with continued use and why dosing sometimes needs adjustment.

Adulteration refers to contamination or impurity in a product, not the body's adapted response to a drug. Potentiation is when one drug increases the effect of another, not when the effect of a single drug diminishes with repeated use. A stimulant is a class of drugs that increases activity or alertness, not the change in response with repeated exposure.