ANGINA PECTORIS, or chest pain on exertion, may be the first symptom of impending heart attack. Chest pain results when the supply of blood fails to meet demand, preventing the heart muscle cells from getting enough oxygen to pump at required levels. Insufficient oxygen delivery usually results from the buildup of calcified fatty plaque in the arteries that diminishes blood flow.
DRUG TREATMENT for angina generally involves beta blockers, calcium channel blockers, nitrates, or some combination of them. Beta-blockers reduce angina pain by preventing the nervous system from stimulating the heart to work harder. Calcium-channel blockers do it by dilating the blood vessels, making more room for blood to flow. Both can have side-effects from annoying to life-threatening. A combination of low doses of these drug types has become popular in angina treatment on the theory that the combination will cover more bases with fewer side effects. But recent data suggest that in most patients, combination therapy actually increases side-effects, without increasing benefits.
Nitrates include nitroglycerin, isosorbide dinitrate, and pentaerythritol tetra nitrate. They work by dilating the blood vessels in the heart. They don't affect peripheral blood vessels but do dilate blood vessels in the head, with headaches as a side-effect in up to 50% of users. Nitroglycerin tablets that can be dissolved under the tongue are used either to relieve attacks in progress, or to prevent anticipated attacks from exertion.
Transdermal patches let controlled doses of the drug enter the bloodstream through the skin. They are not used for acute attacks due to an hour or two delay in maximum concentration. Continuous doses can cause the body to develop a tolerance to the drug. Due to these and withdrawal problems, one study concluded risks outweigh the benefits.
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