Question

An immunologically mediated reaction producing stereotype symptoms which are unrelated to the pharmacodynamic profile of the drug, generally occur even with much smaller doses and have a different time course of onset and duration is called as:

• A. Drug addiction
• B. Drug dependence
• C. Drug hypersensitivity
• D. Drug habituation

Hint:

Remember:
- Type A reaction = Pharmacological (predictable, e.g., bradycardia from beta-blockers).
- Type B reaction = Immunological Idiosyncratic (unpredictable, e.g., penicillin anaphylaxis) $\rightarrow$ Drug Hypersensitivity.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Adverse drug reactions (ADRs) are categorized into Type A (predictable, dose-dependent, based on the drug's pharmacology) and Type B (idiosyncratic, unpredictable, dose-independent, often immunologically mediated).

Step 2: Detailed Explanation:
Let us evaluate the listed pharmacological terms:
- Drug addiction dependence habituation: These refer to the behavioral or psychological states where an animal or human develops a compulsive need to continue taking a drug due to adaptive neuro-chemical changes, rather than an immunological reaction.
- Drug hypersensitivity (Drug allergy): This is a Type B adverse drug reaction.
It is mediated by the immune system (involving IgE antibodies, T-cells, or immune complexes).
Because it is immunologically mediated, it requires prior exposure (sensitization) to the drug, can be triggered by extremely small doses, is entirely unrelated to the drug's primary therapeutic mechanism, and produces a stereotyped allergic syndrome (like urticaria, anaphylaxis, or contact dermatitis).

Step 3: Final Answer:
The described immunological, dose-independent reaction is known as drug hypersensitivity.