Prazosin, terazosin, and doxazosin reduce arteriolar resistance and increase venous capacitance as a consequence of alpha1 adrenergic receptor blockade. The short-term increase in heart rate and plasma renin levels do not persist although the vasodilation continues.

Renal blood flow is maintained.

Retention of salt and water occurs.

Alpha1-adrenergic receptor blockers reduce plasma triglycerides, total and LDL-cholesterol, and increase HDL-cholesterol.

Adverse Effect:

• Inital-dose marked orthostatic hypotension is seen in about 50% of cases.