Which condition is a severe, life-threatening hypersensitivity to a drug usually occurring within minutes?

• A. Hypersensitivity
• B. Adverse drug effect
• C. Antagonism
• D. Anaphylaxis

Answer: (D)

Anaphylaxis is a rapid, life-threatening hypersensitivity reaction to a drug that typically appears within minutes after exposure. It happens when immune mediators released from mast cells and basophils trigger widespread effects—airway swelling and bronchospasm, a sudden drop in blood pressure, hives or angioedema, and potentially loss of consciousness. Because it can quickly compromise breathing and circulation, it requires urgent emergency treatment with epinephrine, airway support, and rapid medical care.

Other terms don’t fit this description as precisely: hypersensitivity is a broad term for an immune reaction to a drug that can be delayed or less severe; an adverse drug effect is any harmful reaction to a drug, not necessarily rapid or life-threatening; antagonism is when one drug reduces the effect of another, not an immune-mediated reaction.