CNS Pharmacology USMLE Step 1 Practice Question
A 24-year-old woman with a history of severe motion sickness is planning a transatlantic cruise lasting seven days. Her physician prescribes a transdermal patch applied behind the ear, delivering 1 mg of medication over 72 hours. Vitals: HR 72, BP 118/76, RR 14, Temp 37°C. Physical examination reveals bilateral pupils that are equal and reactive to light. She denies visual disturbances or headaches. Which of the following drugs most likely prevents nausea by blocking muscarinic receptors in the vestibular system and produces anticholinergic side effects including dry mouth and mydriasis?
Answer choices
- AMeclizine
- BMetoclopramide
- CAprepitant
- DOndansetron
- EScopolamineCorrect answer
- FPromethazine
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.