Question

Which of the following statements are not true about Type B adverse drug reactions?
(A). Qualitatively abnormal responses to the drug
(B). Predictable from the drug's known pharmacological or toxicological effects
(C). Generally dose-dependent
(D). Usually common
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (C) and (D) only.
• C. (B), (C) and (D) only.
• D. (A) and (D) only.

Hint:

Remember the classification:
Type A = Augmented (Dose-dependent, Predictable, Common)
Type B = Bizarre (Dose-independent, Unpredictable, Rare)

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Adverse drug reactions (ADRs) are broadly classified into:
- Type A (Augmented): Predictable, dose-dependent, common, and related to the known pharmacology of the drug.
- Type B (Bizarre): Unpredictable, dose-independent, uncommon, and unrelated to the primary pharmacological action of the drug.
Detailed Explanation:
Let us evaluate each statement in the context of Type B reactions:
- Statement (A): Type B reactions represent qualitatively abnormal, idiosyncratic, or immunologically mediated (hypersensitivity) responses that differ from the drug's intended effect. This statement is TRUE.
- Statement (B): Type B reactions are completely unpredictable based on the known pharmacological or toxicological properties of the drug. This statement is FALSE.
- Statement (C): These reactions are independent of the dose administered; even a microscopic amount of the drug can trigger a severe allergic or anaphylactic response. This statement is FALSE.
- Statement (D): Type B reactions are rare and uncommon in the general population, though they are often severe and associated with high mortality. This statement is FALSE.

Step 2: Final Answer:
Since statements (B), (C), and (D) are NOT true regarding Type B reactions, the correct option is (C).