Drugs treating angina

• Nitroglycerin is used to treat angina and to prevent angina. When given intravenously, it also is used to reduce hypertension. • Nitroglycerin relaxes vascular smooth muscle and dilates both arterial and venous beds. Dilation of veins is more predominant than dilation of arteries, resulting in peripheral pooling of blood and decreased preload. • Blood pressure decreases as a result of venous dilation. Refl ex tachycardia may follow the drop in blood pressure. Thus, the patient's blood pressure is assessed before each dose and during drug therapy with nitroglycerin, and the pulse should be assessed during therapy. • Arteriolar dilation reduces systemic vascular resistance and arterial pressure, thus reducing afterload. Reduced afterload decreases the work the heart must perform to eject blood from the left ventricle and thereby decreases the oxygen needs of the heart. • The most common adverse effect of nitroglycerin is headache. • When nitroglycerin is given intravenously because of elevated blood pressure, the patient must be continually monitored in an intensive care setting. For safety, the drug should be administered by pump.