Aprepitant is added to ondansetron and dexamethasone for highly emetogenic chemotherapy. Its antiemetic mechanism is blockade of which receptor?
- A 5-HT3 receptor
- B Neurokinin-1 (NK1) receptor ✓
- C Muscarinic M1 receptor
- D Dopamine D2 receptor
Correct answer: B. Neurokinin-1 (NK1) receptor
Explanation
Aprepitant is a selective neurokinin-1 (NK1) receptor antagonist that blocks substance P in the vomiting center. It is specifically effective for delayed-phase chemotherapy-induced nausea and vomiting, where substance P plays the dominant role. 5-HT3 blockade is ondansetron's mechanism. Dopamine D2 blockade is metoclopramide/prochlorperazine.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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