Carvedilol provides additional benefit in chronic heart failure beyond what metoprolol offers in terms of antioxidant activity. Which structural-pharmacological feature accounts for both its broader adrenergic blockade and its antioxidant effect?

• A Selective beta-2 agonist activity with intrinsic sympathomimetic action
• B Calcium channel blockade through dihydropyridine structure
• C Selective alpha-2 agonism suppressing central sympathetic outflow
• D Nonselective beta blockade plus alpha-1 blockade, with a carbazole moiety that scavenges free radicals ✓

Explanation

Carvedilol blocks beta-1, beta-2, and alpha-1 receptors, producing vasodilation in addition to negative chronotropy, and it has no intrinsic sympathomimetic activity, which is desirable in heart failure. Its carbazole core confers antioxidant and antiproliferative actions, inhibiting oxygen radical generation and vascular smooth muscle proliferation. Option A is wrong because carvedilol is an antagonist, not an agonist, and partial agonists like xamoterol were harmful in heart failure.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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