Autonomic Pharmacology USMLE Step 1 Practice Question
A 55-year-old woman with a 10-year history of hypertension and angina pectoris is started on labetalol 200 mg twice daily. She also has mild persistent asthma managed with albuterol as needed. One week after initiating labetalol, she presents to clinic reporting progressive fatigue, dyspnea on exertion, and increased wheezing unresponsive to her usual albuterol inhaler. Vital signs are: BP 98/62 mmHg, HR 48 bpm, RR 22, SpO2 92% on room air. Physical examination reveals diffuse end-expiratory wheeze bilaterally. Troponin and BNP are normal. Chest X-ray is clear. Which of the following best explains her clinical deterioration?
Answer choices
- AEnalapril-induced persistent dry cough leading to dyspnea
- BDiltiazem causing excessive atrioventricular nodal blockade with reduced cardiac output
- CHydralazine-mediated reflex tachycardia exacerbating angina
- DLabetalol's non-selective beta-blockade causing bronchospasm and bradycardiaCorrect answer
- EAmlodipine-induced peripheral edema mimicking pulmonary congestion
- FAtenolol precipitation of acute decompensated heart failure
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