A patient with pheochromocytoma crisis is inadvertently given IV propranolol without prior alpha-blockade. The expected outcome is:

• A Successful blood pressure reduction via cardiac β1-blockade
• B Paradoxical hypertensive surge due to unopposed α1-receptor stimulation ✓
• C Bradycardia followed by reflex vasodilation and hypotension
• D Hypertensive crisis prevention through β2 blockade in peripheral vessels

Explanation

In pheochromocytoma, catecholamines stimulate both α and β receptors. By blocking β2 receptors (which mediate vasodilation) without blocking α1 receptors, propranolol leaves α1-mediated vasoconstriction unopposed, causing a dangerous hypertensive surge. This is why α-blockade (phenoxybenzamine) must precede any β-blocker use in pheochromocytoma management.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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