JEE Main levelSingle correct optionDifficulty 2 of 3el016
Cimetidine reduces the secretion of acid in the stomach by preventing histamine from binding to its receptors in the stomach wall. Cimetidine is therefore best described as
Aan agonist of the histamine receptor
Ba base that neutralises hydrochloric acid already present
Ca receptor antagonist (antihistamine) at the stomach receptors
Dan allosteric activator of an enzyme
Answer: C
The drug occupies the receptor and prevents histamine from binding, so no signal for acid secretion is sent. A molecule that blocks a receptor without activating it is an antagonist. It does not neutralise acid chemically.