Which statement best describes the role of alpha-1 blockers in hypertension?

Which statement best describes the role of alpha-1 blockers in hypertension?

• A. They are first-line treatments for essential hypertension.
• B. They lower peripheral vascular resistance and BP but cause orthostatic hypotension and first-dose syncope; generally not first-line, used for BPH or certain indications.
• C. They do not cause orthostatic hypotension.
• D. They cause hyperkalemia as a common adverse effect.

Answer: (B)

Alpha-1 blockers lower blood pressure by blocking alpha-1 adrenergic receptors on vascular smooth muscle, which reduces peripheral vascular resistance and systemic BP. However, they carry a high risk of orthostatic hypotension and, in particular, a first-dose syncope phenomenon, because the initial vasodilation can cause a sudden drop in BP when standing. For this reason they are not used as first-line therapy for essential hypertension; they’re mainly reserved for other indications such as benign prostatic hyperplasia, where their smooth muscle–relaxing effects in the bladder and prostatic urethra provide benefit. Hyperkalemia is not a common adverse effect of alpha-1 blockers (unlike with ACE inhibitors, ARBs, or potassium-sparing diuretics). Dizziness and tachycardia can accompany the BP drop and contribute to their limited role as antihypertensives.

Alpha-1 blockers lower blood pressure by blocking alpha-1 adrenergic receptors on vascular smooth muscle, which reduces peripheral vascular resistance and systemic BP. However, they carry a high risk of orthostatic hypotension and, in particular, a first-dose syncope phenomenon, because the initial vasodilation can cause a sudden drop in BP when standing. For this reason they are not used as first-line therapy for essential hypertension; they’re mainly reserved for other indications such as benign prostatic hyperplasia, where their smooth muscle–relaxing effects in the bladder and prostatic urethra provide benefit. Hyperkalemia is not a common adverse effect of alpha-1 blockers (unlike with ACE inhibitors, ARBs, or potassium-sparing diuretics). Dizziness and tachycardia can accompany the BP drop and contribute to their limited role as antihypertensives.