Alphamethyldopa, clonidine, and guanfacine act on the brain to lower blood pressure. Doxazosin, guanadrel, guanethedine, mecamylamine,phenoxybenzaline, prazosin, and terazosin act on the nerves that innervate smooth muscle in the walls of the blood vessels so that the vessels dilate and blood pressure drops. Hydralazine and minoxidil directly act on the smooth muscle in the walls of blood vessels to dilate them and lower blood pressure.
Reserpine reduces the level of adrenalin-like substances in the body.
Terazosin is also commonly used to treat voiding problems in men with enlarged prostate glands. Minoxidil has the side effect of causing hair growth and is now most commonly used as a treatment for baldness. High blood pressure may also respond to lifestyle changes. See High Blood Pressure .