A 42-year-old man with a 3-year history of episodic severe headaches, palpitations, and profuse diaphoresis is found to have sustained hypertension (160/95 mmHg). Imaging reveals an encapsulated tan-brown adrenal mass (marked **A** in the diagram) measuring 4.5 cm with central hemorrhage. Biochemical testing confirms elevated plasma free metanephrines (3.2× upper limit of normal). The structure marked **A** in the diagram is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla. Prior to surgical resection, which of the following pharmacologic approaches is most appropriate for pre-operative management?

Explanation

## Why "Begin alpha-blockade (phenoxybenzamine) first, then add beta-blocker only after adequate blood pressure control is achieved" is right The clinical anchor directly mandates this sequence: **alpha-blockade FIRST, beta-blocker ONLY AFTER adequate alpha-blockade** (typically days 3–7). This is the cardinal rule in pheochromocytoma pre-operative management. Starting beta-blocker before alpha-blockade causes unopposed alpha-adrenergic stimulation, precipitating a hypertensive crisis. Phenoxybenzamine (non-selective irreversible alpha antagonist) is titrated to achieve sitting BP <130/80 mmHg and standing BP ≥90/45 mmHg acceptable; only then is a beta-blocker (propranolol or atenolol) added to control reflex tachycardia. This 10–14 day pre-operative blockade is mandatory before surgery to prevent intra-operative catecholamine surges and hemodynamic catastrophe (Robbins & Cotran, Ch 24; Williams Endocrinology 14e). ## Why each distractor is wrong - **Initiate beta-blocker (propranolol) immediately**: This is the classic error that causes unopposed alpha-adrenergic effect and hypertensive crisis. Beta-blockers must NEVER be started first; they unmask alpha-mediated vasoconstriction when catecholamine levels are uncontrolled. - **Start combined alpha- and beta-blockade simultaneously**: While both drugs are eventually needed, simultaneous initiation violates the mandatory sequence. Alpha-blockade must precede beta-blockade by several days to expand intravascular volume and achieve hemodynamic stability before reflex tachycardia is addressed. - **Administer metyrosine alone**: Metyrosine (tyrosine hydroxylase inhibitor) is an alternative for catecholamine synthesis inhibition but is not first-line and is rarely used as monotherapy. It is slower-acting than adrenergic blockade and does not address the acute hemodynamic threat; it may be used as adjunctive therapy in refractory cases. **High-Yield:** Alpha-blocker FIRST (phenoxybenzamine), then beta-blocker days 3–7 AFTER adequate alpha-blockade — the sequence is non-negotiable; starting beta-blocker first = unopposed alpha = hypertensive crisis. [cite: Robbins and Cotran Pathologic Basis of Disease 10e Ch 24 (Endocrine System); Williams Endocrinology 14e]