Autonomic Pharmacology USMLE Step 1 Practice Question
A 22-year-old man is brought to the emergency department because of agitation after ingesting an unknown amount of jimson weed at a party. His temperature is 39.8°C, heart rate is 128/min, and blood pressure is 145/90 mmHg. He is flushed, febrile, and delirious. His skin is dry, pupils are dilated to 8 mm bilaterally, mucous membranes are dry, and bowel sounds are decreased. Urinary retention is noted on abdominal examination. Which of the following best explains the mechanism of the agent responsible for his findings?
Answer choices
- ACompetitive antagonism of muscarinic acetylcholine receptorsCorrect answer
- BIncreased release of norepinephrine from presynaptic vesicles
- CIrreversible inhibition of acetylcholinesterase
- DActivation of nicotinic ganglionic receptors
- EAlpha 2 agonism in the central nervous system
- FCompetitive antagonism of nicotinic acetylcholine receptors at the neuromuscular junction
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