Which term describes an abnormal immune response to a drug due to antibody formation?

• A. Allergy
• B. Anaphylaxis
• C. Idiosyncrasy
• D. Systemic Effect

Answer: (A)

Abnormal immune response to a drug due to antibody formation is allergy. When the immune system becomes sensitized to a medication, it may produce antibodies that trigger an immune reaction upon subsequent exposure. This reaction involves immune cells releasing mediators like histamine, leading to symptoms such as skin rashes, itching, swelling, or respiratory symptoms. Anaphylaxis is a severe, life-threatening form of an allergic reaction, so it’s a specific extreme manifestation rather than the general term for the immune-mediated response. Idiosyncrasy refers to an unpredictable, non-immune reaction that isn’t driven by antibodies, and a systemic effect describes broad, non-specific effects of a drug. Therefore, allergy best describes the antibody-mediated abnormal immune response to a drug.