Question

Which of the following describes the mechanism of action of metoclopramide as an antiemetic?

• A. H\textsubscript{1} and H\textsubscript{2}-receptor blocking effect
• B. M-cholino receptor stimulating effect
• C. D\textsubscript{2}-dopamine and 5-HT\textsubscript{3}-serotonin receptor blocking effect
• D. M-cholino receptor blocking effect

Hint:

Metoclopramide = D\textsubscript{2} & 5-HT\textsubscript{3} antagonist → antiemetic.

Answer 1

The Correct Option is C

Metoclopramide exerts its antiemetic effect primarily by blocking D\textsubscript{2} receptors in the chemoreceptor trigger zone (CTZ) and 5-HT\textsubscript{3} receptors in the GI tract and CNS. This dual action reduces nausea and vomiting.