## Understanding Pheochromocytoma Management ### The Correct Answer (Option B) — The EXCEPT Answer **Key Point:** The statement that phenoxybenzamine is universally "preferred over" selective alpha-1 blockers **because of irreversible blockade** is not an absolute truth — it is debatable and institution-dependent. While phenoxybenzamine (a non-selective, irreversible alpha-blocker) has historically been the drug of choice for pre-operative preparation in pheochromocytoma, **selective alpha-1 blockers (doxazosin, prazosin, terazosin) are now widely used and considered equally effective** in many centers. Current evidence and guidelines (Endocrine Society 2014) acknowledge both approaches as acceptable. Selective agents are often preferred due to: - Better tolerability (less reflex tachycardia, less post-operative hypotension) - Shorter duration of action (easier to manage intraoperatively) - Comparable efficacy in controlling blood pressure Thus, the claim that phenoxybenzamine is definitively "preferred" solely because of irreversible blockade is **not universally true**, making Option B the EXCEPT answer. ### Why the Other Options Are TRUE (and therefore NOT the answer) | Option | Statement | Verdict | |--------|-----------|---------| | **A** | Alpha-blockade before beta-blockade to prevent hypertensive crisis | ✅ TRUE — cardinal rule; beta-blockade alone causes unopposed alpha stimulation → severe hypertension | | **C** | Beta-blockers must never be used without prior alpha-blockade due to risk of unopposed alpha effects | ✅ TRUE — in a **hypertensive** pheochromocytoma patient (as in this stem), this is the standard teaching; unopposed beta-blockade → paradoxical hypertension and coronary vasospasm | | **D** | Surgical resection is definitive treatment after adequate pharmacological preparation | ✅ TRUE — adrenalectomy after 7–14 days of alpha (then beta) blockade is the gold standard | **High-Yield:** The sequence remains alpha → beta → surgery. However, the choice between phenoxybenzamine and selective alpha-1 blockers is NOT absolute — both are acceptable per current guidelines. **Clinical Pearl:** Phenoxybenzamine causes irreversible alpha-blockade and may lead to prolonged post-operative hypotension. Many modern centers prefer doxazosin for its reversibility and tolerability. This nuance is a classic exam trap. [cite: Harrison's Principles of Internal Medicine 21e, Ch. 397; Endocrine Society Clinical Practice Guideline on Pheochromocytoma/Paraganglioma, JCEM 2014]
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