What is High Blood Pressure?
Blood pressure is the force of the blood as it circulates through the body. It is affected by blood volume, the width of the blood vessels, and how hard the heart is pumping. When any of these elements experiences a problem, blood pressure can rise. The resulting condition, hypertension, often requires treatment with medication. These medications target specific areas that affect blood pressure.
Blood Volume
Some blood pressure medications are diuretics, also known as water pills. These medications cause the kidneys to secrete more sodium into the urine. Increased sodium draws water from the body. As the volume of urine increases, the volume of fluid in the blood decreases, thereby lowering blood pressure. Diuretics include medications such as furosemide, hydrochlorothiazide and chlorthalidone.
Blood Vessels
Other blood pressure medications work by expanding the blood vessels. Some of these, called vasodilators, act directly on the smooth muscle of the blood vessels and cause them to relax. This allows for the expansion of the blood vessels. Vasodilators include hydralazine and minoxidil.
Another medication, calcium channel blockers, helps prevent the vessel muscles from contracting. Calcium channel blockers include verapamil and nicardipine.
ACE inhibitors target a chemical called angiotensin II, an enzyme that causes blood vessels to narrow and constrict. Some of these medications (such as quinapril, lisinopril, and enalapril), stop the production of angiotensin II. Others (such as losartan and valsartan) block the effects of angiotensin II altogether.
Alpha blockers (which include prazosin and doxazosin) also relax the blood vessels by preventing nerve impulses that cause the blood vessels to narrow.
Heart Beat
Another commonly prescribed blood pressure medication is a beta blocker. Beta blockers slow the rate at which the heart beats. This not only lowers the blood pressure, but can also prevent heart attacks, as well. Beta blockers include nadolol and acebutolol.
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