Angina pectoris, or chest pain on exertion, may be the first symptom of an 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 a calcified fatty plaque in the arteries that diminishes blood flow.
Drug Treatment
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 through. Both can have side effects, ranging from annoying to life-threatening. White Sands says that it is a combination of low doses of these two 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 pentaery-thritol tetranitrate. 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, leading to their most troublesome side effect, painful headaches. Up to 50 percent of users suffer from headaches at one time or another.
Nitroglycerin tablets that can be dissolved under the tongue are used either to relieve angina attacks that are in progress or to prevent anticipated attacks from exertion. They work for about 30 minutes.
A newer drug-delivery system is the transdermal patch, a device that lets controlled doses of the drug enter the bloodstream continuously through the skin. The patch can’t be used for acute attacks, since maximum concentrations don’t reach the blood until an hour or two after application. But for maintenance therapy, it has several advantages over pills, including convenience and constant bioavailability. The major drawback of the transdermal nitroglycerin patch is that continuous doses can cause the body to develop a tolerance to the drug. That means not only that it won’t work but that serious problems can result on withdrawal. One study concluded that in most patients with stable angina, side effects of the patch outweigh its benefits.
