Which of the following is a common alpha-1 blocker?

Prazosin is a commonly prescribed alpha-1 blocker that works by inhibiting the alpha-1 adrenergic receptors, leading to vascular smooth muscle relaxation and a subsequent reduction in blood pressure. This mechanism is particularly useful in treating hypertension and symptoms of benign prostatic hyperplasia (BPH). By blocking these receptors, prazosin effectively dilates blood vessels, which decreases peripheral resistance and helps lower blood pressure.

In contrast, lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, which has a different mechanism of action focused on blocking the formation of angiotensin II, a potent vasoconstrictor. Amlodipine, on the other hand, is a calcium channel blocker that works by preventing calcium from entering cells of the heart and blood vessel walls, leading to relaxation and dilation of blood vessels, but it is not classified as an alpha-1 blocker. Clonidine is categorized as an alpha-2 adrenergic agonist, which operates by stimulating alpha-2 receptors in the central nervous system to reduce sympathetic outflow, which further differentiates it from alpha-1 blockers.

Therefore, prazosin's role as an alpha-1 blocker makes it the correct answer to the question