An exaggerated reaction to a normally tolerated substance is known as...

• A. Indication
• B. Hypersensitivity
• C. Adverse Effect
• D. Cumulative Action

Answer: (B)

An exaggerated immune response to a normally tolerated substance is hypersensitivity. This means the body's immune system overreacts to something that is usually harmless, such as a drug or allergen, leading to symptoms that can range from itching or hives to life-threatening anaphylaxis. Because hypersensitivity is immune-mediated, it isn’t simply about dose or the drug’s intended effect; it’s about how the immune system recognizes the substance as a threat and mounts an amplified reaction.

In contrast, an adverse effect is any harmful or undesired effect of a drug that isn’t necessarily immune-driven and can occur even at typical doses. Cumulative action refers to increased effects from repeated dosing due to drug buildup in the body. An indication is simply the approved use or purpose for a drug.