Nitrates.

Nitrates have been used for the last 130 years to treat and control the symptoms of angina pectoris. Within the last 15 years, nitrates also have been shown to limit infarct size and to be beneficial in the treatment of patients with severe intractable heart failure, cardiogenic shock, severe mitral and aortic regurgitation, hypertensive episodes, and portal hypertension. The adequate use of nitrates to treat these disorders requires the ability to document a hemodynamic response and to closely monitor the adverse consequences of this therapy. Nitrates work by directly relaxing smooth muscle in resistance and capacitance vessels, thereby causing generalized dilation. Nitrates reduce preload and, at higher doses, reduce systemic vascular resistance and afterload. This chapter reviews the physiologic mechanisms that underlie nitrate therapy, the appropriate indications for nitrate use, the usefulness of specific agents, and their appropriate nursing implications.