Prazosin as initial antihypertensive therapy: correlates of sympathetic function

Area of Science:

• Cardiovascular Medicine
• Pharmacology
• Hypertension Research

Background:

• Abnormal sympathetic nervous system activity is implicated in essential hypertension.
• Prazosin hydrochloride, a selective alpha-blocker, offers a peripheral antisympathetic mechanism.
• This mechanism may provide an advantage over other antihypertensive drugs.

Purpose of the Study:

• To evaluate the efficacy of prazosin hydrochloride in managing hypertension.
• To assess its effects on sympathetic and baroreflex function.
• To determine if baseline sympathetic function predicts response to prazosin.

Main Methods:

• A study involving 13 hypertensive patients.
• Monitoring of blood pressure, heart rate, plasma catecholamines, and baroreflex function.
• Assessment of prazosin monotherapy and combination therapy with a thiazide diuretic.

Main Results:

• Prazosin alone significantly reduced diastolic blood pressure without altering heart rate or catecholamines.
• Combination with a thiazide diuretic successfully lowered blood pressure in non-responders.
• Increased plasma renin activity and aldosterone were observed with diuretic addition.
• No clear correlation between baseline sympathetic function and prazosin response was found, though higher norepinephrine levels trended with response.

Conclusions:

• Prazosin hydrochloride is effective in reducing blood pressure in essential hypertension.
• Combination therapy with thiazide diuretics enhances blood pressure control.
• The drug's antisympathetic action is a key mechanism in its antihypertensive effect.