Which of the following medications is an example of an alpha-adrenergic antagonist?

Which of the following medications is an example of an alpha-adrenergic antagonist?

• A. Doxazosin
• B. Oxybutynin
• C. Imipramine
• D. Pseudoephedrine

Answer: (A)

Alpha-adrenergic antagonists block alpha-1 receptors, which reduces smooth muscle tone in vascular beds and in the urinary tract, helping both blood pressure control and urinary flow. Doxazosin is a classic example because it selectively blocks alpha-1 receptors, leading to vasodilation and relief of urinary obstruction in benign prostatic hyperplasia. The other drugs act through different mechanisms: oxybutynin is an antimuscarinic that decreases bladder contractions; imipramine alters norepinephrine reuptake and has anticholinergic effects but does not block alpha-1 receptors; pseudoephedrine is an alpha-adrenergic agonist that causes vasoconstriction, not blockade.

Alpha-adrenergic antagonists block alpha-1 receptors, which reduces smooth muscle tone in vascular beds and in the urinary tract, helping both blood pressure control and urinary flow. Doxazosin is a classic example because it selectively blocks alpha-1 receptors, leading to vasodilation and relief of urinary obstruction in benign prostatic hyperplasia. The other drugs act through different mechanisms: oxybutynin is an antimuscarinic that decreases bladder contractions; imipramine alters norepinephrine reuptake and has anticholinergic effects but does not block alpha-1 receptors; pseudoephedrine is an alpha-adrenergic agonist that causes vasoconstriction, not blockade.