American Medical Association Family Medical Guide - American Medical Association [321]
• Angiotensin-receptor blockers Angiotensin-receptor blockers prevent the arteries from constricting and prevent the kidneys from retaining excess sodium and water. These drugs are usually prescribed for people who cannot use ACE inhibitors. Possible side effects include dizziness, fatigue, or stomach pain.
• Calcium channel blockers Calcium channel blockers prevent blood vessels from constricting and interfering with blood flow. Because some of these drugs can slow the heart rate, they are also used to treat some types of arrhythmias. Possible side effects include dizziness, nausea, headache, flushing of the skin, ankle swelling, or fatigue.
• Nitrate drugs Nitrate drugs such as nitroglycerin dilate (widen) the blood vessels, improving blood flow. Both short-acting and long-acting nitrates are available. A small tablet of nitroglycerin placed under the tongue usually relieves an episode of angina (chest pain) in 1 to 3 minutes. The effects of this short-acting nitrate drug last about 30 minutes. People who have chronic (long-lasting) stable angina are usually advised to carry nitroglycerin with them at all times. Some people learn to take the nitroglycerin just before they reach the level of exertion they know can induce their angina. Long-acting nitrate drugs are taken one to four times daily. They are available as skin patches and a paste, which allow the medication to be absorbed through the skin over many hours. Over time, long-acting nitrates lose their ability to provide relief. Doctors often recommend that people try to go 8- to 12-hour periods without taking the drug as a way to help maintain its effectiveness. Possible side effects include headache, flushing of the skin, or dizziness.
• Digitalis drugs Digitalis drugs strengthen the force of the heart’s contractions by increasing the supply of calcium to the heart muscle. These drugs are used to treat heart failure and arrhythmias. Possible side effects include nausea, loss of appetite, fatigue, or disturbed vision.
• Anticoagulants, antiplatelet agents, and thrombolytics Anticoagulants, antiplatelet agents, and thrombolytics are anticlotting drugs that help prevent the formation of blood clots. Aspirin and other anticlotting drugs bind to platelets (cell fragments that enable blood to clot) and keep them from clumping on blood vessel walls, significantly reducing the risk that a blocked artery will cause a second heart attack. Thrombolytics such as streptokinase or tPA (tissue plasminogen activator) are often given intravenously (through a vein) during a heart attack to dissolve an existing clot that is blocking a coronary artery. These drugs can cause bleeding in some people.
Additional classes of medications used to also treat high blood pressure include the following:
• Alpha blockers Alpha blockers help lower blood pressure by preventing the blood vessels from constricting. These drugs also interfere with the effects of hormones in the body that normally raise blood pressure. Alpha blockers are often prescribed in combination with other types of antihypertensive medications. Possible side effects include dizziness, headache, or mild fluid retention.
• Vasodilators Vasodilators widen the arteries by acting directly on the smooth muscle of the artery walls. These medications are usually given only in emergencies, when blood pressure cannot be controlled with other drugs. Possible side effects include headache, increased fluid retention, and an unusually strong, rapid heartbeat (more than 100 beats per minute).
• Centrally acting drugs Centrally acting drugs lower blood pressure by acting directly on the brain and nervous system to reduce heart rate and prevent blood vessels from constricting. These drugs may be used in combination with diuretic drugs. Possible