Prazosin differs from phenoxybenzamine in that prazosin is a:

• A Non-selective, irreversible α-blocker
• B Selective α1, competitive (reversible) blocker ✓
• C Selective α2, competitive blocker
• D Non-selective, competitive α-blocker

Explanation

Prazosin is a selective α1-adrenoceptor antagonist that binds competitively and reversibly, making its block surmountable by increasing agonist concentration. Phenoxybenzamine is a non-selective (α1 + α2), irreversible (covalent haloalkylamine) blocker. Selective α1 blockade by prazosin avoids the reflex tachycardia seen with non-selective blockade, because presynaptic α2-mediated feedback inhibition remains intact.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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