Which statement best defines a paradoxical reaction?

Which statement best defines a paradoxical reaction?

• A. A drug causes the opposite effect of what is expected
• B. A drug causes no effect
• C. A drug increases tolerance
• D. A drug only causes local irritation

Answer: (A)

A paradoxical reaction means the drug produces the opposite of the intended or expected effect. This happens when a medication that is supposed to calm or sedate instead causes agitation, excitement, or other counterproductive responses in some people. That’s why the statement describing a drug causing the opposite of what is expected best defines a paradoxical reaction. Other possibilities don’t fit this concept: a drug that has no effect is simply no effect, not the opposite of the intended effect; a drug that increases tolerance refers to needing more of the drug to achieve the same effect, not an opposite response; and a drug that only causes local irritation is a local adverse effect, not a systemic opposite reaction.

A paradoxical reaction means the drug produces the opposite of the intended or expected effect. This happens when a medication that is supposed to calm or sedate instead causes agitation, excitement, or other counterproductive responses in some people. That’s why the statement describing a drug causing the opposite of what is expected best defines a paradoxical reaction.

Other possibilities don’t fit this concept: a drug that has no effect is simply no effect, not the opposite of the intended effect; a drug that increases tolerance refers to needing more of the drug to achieve the same effect, not an opposite response; and a drug that only causes local irritation is a local adverse effect, not a systemic opposite reaction.