Karnataka PGET 2007 Pharmacology MCQ Answer 03

The correct answer is A

Type A Reactions: Adverse drug reactions are generally classified as type A or type B, but some drug reactions do not fit well into either category. Type A (augmented) reactions are normal pharmacologic effects of the drug exaggerated to the point of being undesirable or intolerable for patients.

These ADRs are often dose-dependent, and the percentage of patients who might experience these effects is generally predictable. Examples of drugs indicated as causing type A reactions include warfarin or heparin, which cause bruising; or diphenhydramine, which causes drowsiness. Another form of type A reaction involves a drug’s recognized pharmacologic property other than the primary desired one. For example, b-adrenergic blocking agents exert their effect on receptors other than those targeted in the heart and vasculature, leading to the potential of bronchospasm due to b-blockade of certain receptors in the pulmonary tree.

Type B Reactions: Type B (bizarre) reactions are often more severe adverse effects unrelated to the known pharmacologic action of the drug and include most immunologic reactions. Unless patients are tested for antibody markers, these reactions are unpredictable and may or may not be dose-dependent. An example of a type B reaction is an anaphylactic reaction to penicillin. The term “idiosyncratic reactions” has also been used in place of type B adverse reactions.

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Category: Karnataka PGET 2007 MCQs