High Blood Pressure Treatment (cont.)
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Beta-blockers
The sympathetic nervous system is a part of the nervous system that helps to
regulate certain involuntary (autonomic) functions in the body such as the
function of the heart and blood vessels. The nerves of the sympathetic nervous
system extend throughout the body and exert their effects by releasing chemicals
that travel to nearby cells in the body. The released
chemicals bind to receptors (molecules) on the surface of the nearby cells and
stimulate or inhibit the function of the cells. In the heart and blood vessels,
the receptors for the sympathetic nervous system that are most important are the
beta receptors. When stimulated, beta-receptors in the heart increase the heart
rate and the strength of heart contractions (pumping action).
Beta-blocking
drugs acting on the heart slow the heart rate and reduce the force
of the heart's contraction.
Stimulation of beta-receptors in the smooth muscle of the peripheral arteries and in the airways of the lung causes these muscles to relax. Beta-blockers cause contraction of the smooth muscle of the peripheral arteries and thereby decrease blood flow to body tissues. As a result, the patient may experience coolness in the hands and feet. In response to the beta-blockers, the airways are squeezed (constricted) by the contracting smooth muscle; this squeezing (impingement) on the airway causes wheezing, especially in individuals with a tendency for asthma. In short, beta-blockers reduce both the force of the heart's pumping action and the blood pressure that the heart generates in the arteries.
Beta-blockers remain useful medications in treating hypertension, especially in patients with a fast heartbeat while resting (tachycardia), cardiac chest pain (angina), or a recent heart attack (myocardial infarction). Beta-blockers appear to improve long-term survival when given to patients who have had a heart attack. Whether beta-blockers can prevent heart problems (are cardio-protective) in patients with hypertension any more than other anti-hypertensive medications is uncertain. Beta-blockers may be considered for treatment of hypertension because they also may treat co-existing medical problems; such as chronic anxiety or migraine headaches in people with hypertension. The common side effects of these drugs include depression, fatigue, nightmares, sexual impotence in males, and increased wheezing in people with asthma.
The
beta-blockers include:
Next: Diuretics »
- ACE Inhibitors - Read about ACE inhibitors like Altace, lisinopril, enalapril, ramparil, Zestril and more. Information includes side effects, drug interactions, and pregnancy safety information.
- Congestive Heart Failure - Read about congestive heart failure symptoms like fatigue, abdomen, leg and ankle swelling, shortness of breath, sleeplessness, increased urination, nausea, abdominal pain, and decreased appetite.
- Beta Blockers - Learn more about Beta Blockers, a drug that treats angina and other heart rhythm disorders, migraines, high blood pressure, panic attacks, and tremors. Generic and brand names are included in the article.
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