Autonomic Pharmacology USMLE Step 1 Practice Question

A 43-year-old woman presents with episodic headaches, diaphoresis, and palpitations. During an acute episode, vital signs show BP 198/112 mm Hg, HR 118/min, RR 20/min, and temp 37.2°C. Plasma metanephrines are markedly elevated at 850 pg/mL (normal <90). CT imaging reveals a 3-cm left adrenal mass. She denies chest pain. She takes no current medications. Which drug should be initiated preoperatively to prevent hypertensive crises during surgical resection?