Which describes Type B adverse drug reactions?

Which describes Type B adverse drug reactions?

• A. Unpredictable due to mechanisms not understood
• B. Exaggeration of effects
• C. Persist for a long time
• D. Take time to develop

Answer: (A)

Type B adverse drug reactions are unpredictable idiosyncratic events that occur independently of dose and often arise from immune or other uncommon mechanisms that aren’t well understood. This makes the description “unpredictable due to mechanisms not understood” the best match. In contrast, Type A reactions are predictable and dose-related, reflecting the drug’s known pharmacologic effects (exaggeration of effects). While reactions can sometimes persist or have delayed onset, those features don’t define Type B as clearly as the element of unpredictability and unknown mechanism does.

Type B adverse drug reactions are unpredictable idiosyncratic events that occur independently of dose and often arise from immune or other uncommon mechanisms that aren’t well understood. This makes the description “unpredictable due to mechanisms not understood” the best match. In contrast, Type A reactions are predictable and dose-related, reflecting the drug’s known pharmacologic effects (exaggeration of effects). While reactions can sometimes persist or have delayed onset, those features don’t define Type B as clearly as the element of unpredictability and unknown mechanism does.