High blood pressure is a common precursor to cardiac events such as heart attack or stroke. Along with dietary measures, exercise, weight management and smoking cessation, the use of prescription drugs is widely accepted as a method of regulating blood pressure. The Merck Manual lists eight primary categories of blood pressure medication.
Diuretics
Diuretics reduce blood volume, thus decreasing the amount of pressure exerted by the blood on the heart and blood vessels. This result is achieved through the diuretic's abiity to increase the excretion of excess water and sodium from the body. Diuretics are often a physician's first pharmaceutical recommendation in attempting to reduce blood pressure, according to the Mayo Clinic.
Beta-blockers
Beta-blockers work by reducing nerve signals to the heart and blood vessels, thus relaxing the muscular force exerted by the heart, slowing its rate, and opening up the blood vessels, according to the University of Maryland Medical Center. The cumulative effect of these factors produces more space for the blood to flow through, thus reducing the amount of pressure it exerts on the heart and blood vessels.
Calcium Channel Blockers
Calcium channel blockers are vasodilators, meaning that they cause the blood vessels to widen and open up. They do this by blocking calcium from entering the heart and blood vessel cells. As a result the cells relax and blood pressure drops, according to the Mayo Clinic.
Angiotensin-converting Enzyme Inhibitors
Angiotensin-converting enzyme inhibitors, or ACE inhibitors, function by blocking the conversion of the inactive hormone angiotensin I to its active vasoconstricting form, angiotensin II. By blocking the conversion of this hormone, ACE inhibitors allow the blood vessels to relax, thus decreasing blood pressure.
Angiotensin II Receptor Blockers
Angiotensin II receptor blockers prevent the angiotensin II hormone from affecting the blood vessels. In this way, they exert the same blood pressuring lowering result as ACE inhibitors.
Adrenergic Modifiers
Adrenergic modifiers are no longer frequently prescribed due to their negative side effects such as drowsiness and depression, according to the Merck Manual. They function by reducing the activity of nerves that increase blood pressure.
Direct Vasodilators
These drugs act directly on the walls of blood vessels, preventing constriction and widening the vessel so that the blood has more room to flow. Because they are powerful drugs with numerous side effects, direct vasodilators are prescribed as a drug of last resort when other medications have failed.
