High blood pressure (HBP) is a condition affecting about 1 in 3 adults in the United States, according to the Centers for Disease Control and Prevention (CDC). It is defined as a blood pressure reading of 140/90 mmHg or higher. Drugs commonly prescribed for treating HBP are grouped into classes according to their mechanism of action: beta blockers, calcium channel blockers, diuretics (water pills), angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), alpha-blockers and vasodilators. Some of these drugs may be used alone; however, doctors typically prescribe drugs in combinations from two classes.
Beta-blockers
Beta-blockers lower blood pressure by decreasing the force of the heart's contractions and lowering the heart rate. A 2008 article in the "Journal of the American College of Cardiology" notes that some beta-blockers affect the heart only and some also relax blood vessels. Because they reduce the work of the heart, these drugs are especially useful in patients with a history of heart disease or heart attack.
Calcium Channel Blockers
Calcium channel blockers are an older class of drugs for treating HBP. They lower blood pressure by decreasing the force of the heart's contractions and relaxing the muscle in the walls of arteries. These drugs are used for treating migraines and certain vascular diseases, and they are the first choice in patients having HBP and one of these conditions. Side effects of these drugs include: fatigue, headache, flushing and swelling around the ankles.
Diuretics
Diuretics cause the kidneys to pull sodium and water out of the blood, thus lowering the blood volume. There are three main types of diuretics: thiazide, loop and potassium-sparing diuretics. Diuretics are especially beneficial in elderly patients, people who are overweight and people who have heart failure. The Mayo Clinic explains that diuretics are often used in combination therapy with other blood pressure medications and may be used alone to treat mild cases of high blood pressure.
Angiotensin-converting Enzyme (ACE) Inhibitors
ACE inhibitors reduce blood pressure by relaxing blood vessels. They inhibit the production of angiotensin II, a substance that causes blood vessels to constrict. ACE inhibitors are especially beneficial in patients with diabetes, kidney disease, asthma and people who have had heart attacks. These drugs typically produce few side effects, the most common being a persistent dry cough. In sensitive patients, however, the side effects can be severe.
Angiotensin Receptor Blockers
ARBs block special receptors in blood vessels that normally bind the vessel-constricting substance angiotensin II. ARB's have few side effects and are usually prescribed for patients who cannot tolerate the side effects of ACE inhibitors. However the American Heart Association warns that, like other blood pressure-lowering medicines, ARBs may cause nausea, dizziness, headaches and low blood pressure.
Alpha-blockers
Alpha-blockers work by calming the central nervous system. These drugs are typically used in combinations with drugs from other classes and are rarely used as a stand-alone treatment of HBP. Side effects include dizziness, fatigue and visual problems.
Vasodilators
Vasodilators are powerful drugs that reduce blood pressure by dilating (expanding) the blood vessels. They work by relaxing the muscle in the walls of the arteries and large veins. They are rarely used as first-line treatment except in emergency situations where immediate reduction in blood pressure is necessary. Because they reduce blood pressure so rapidly, vasodilators may cause angina (chest pain) and heart attack in patients with existing heart disease.
References
- "Journal of the American College of Cardiology"; Beta Blockers in Hypertension; Kaplan NM; 2008; 52:1490
- Mayo Clinic: High Blood Pressure (Hypertension) -- Choosing Blood Pressure Medications
- American Heart Association: Medications Commonly Used to Treat Heart Failure
