Nitroglycerin shares the actions of other nitrates and nitrites and is used for the acute relief of angina pectoris secondary to coronary artery disease, for prophylactic management in situations likely to provoke angina attacks, and for long-term prophylactic management of angina pectoris. Sublingual nitroglycerin is considered the drug of choice for the acute relief of angina pectoris, because it has a rapid onset of action, is inexpensive, and its efficacy is well established.
IV nitroglycerin is used to control blood pressure in perioperative hypertension, especially hypertension associated with cardiovascular procedures; to control blood pressure in patients with severe hypertension or in hypertensive crises for the immediate reduction of blood pressure in patients in whom such reduction is considered an emergency (hypertensive emergencies), especially those associated with coronary complications (e.g., coronary ischemia, acute coronary insufficiency, acute left ventricular failure, postoperative hypertension [especially following coronary bypass surgery]); and to produce controlled hypotension during surgical procedures.
Hypertensive emergencies are those rare situations requiring immediate blood pressure reduction, although not necessarily to normal ranges, in order to prevent or limit target organ damage. Examples of such emergency situations include hypertensive encephalopathy, intracerebral hemorrhage, unstable angina pectoris, acute myocardial infarction, acute left ventricular failure with pulmonary edema, dissecting aortic aneurysm, and eclampsia. Elevated blood pressure alone, in the absence of symptoms or new or progressive target organ damage, rarely is a hypertensive crisis requiring emergency therapy. If IV nitroglycerin is used in the management of a hypertensive emergency, the initial goal of such therapy is to reduce mean arterial blood pressure by no more than 25% within minutes to 1 hour, followed by further reduction if stable toward 160/100 to 110 mm Hg within the next 2-6 hours, avoiding excessive declines in pressure that could precipitate renal, cerebral, or coronary ischemia. If this blood pressure is well tolerated and the patient is clinically stable, further gradual reductions toward normal can be implemented in the next 24-48 hours. Patients with aortic dissection should have their systolic pressure reduced to less than 100 mm Hg if tolerated.
Acute Myocardial Infarction
The use of nitroglycerin is one of the principal initial therapies in the management of patients with acute myocardial infarction. The drug has been used to reduce myocardial ischemia, alleviate ischemia-induced pain, manage hypertension and persistent pulmonary congestion, and decrease the extent of infarction during and improve survival after acute myocardial infarction. Although sublingual or transdermal nitroglycerin can be used in the management of early acute myocardial infarction, IV therapy with the drug allows for more precise minute-to-minute control. For precautions associated with the use of nitroglycerin in patients with acute myocardial infarction, and also .
Heart Failure and Low-output Syndromes
IV nitroglycerin has been used effectively for the treatment of acutely decompensated (e.g., congestive) heart failure or other low cardiac output states, including those associated with acute myocardial infarction. The precipitating cause of acute heart failure decompensation should be carefully assessed to inform appropriate treatment, optimize outcomes, and prevent future acute events in patients with heart failure. Current guidelines for the management of heart failure in adults generally recommend inhibition of the renin-angiotensin-aldosterone system with a combination of drug therapies, including neurohormonal antagonists (e.g., angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor antagonists, angiotensin receptor-neprilysin inhibitors [ARNIs], β-adrenergic blocking agents [β-blockers], aldosterone receptor antagonists), to inhibit the detrimental compensatory mechanisms in heart failure and reduce morbidity and mortality. ( and in .) IV vasodilators have not been shown to improve outcomes in patients hospitalized for heart failure; however, in the absence of symptomatic hypotension, IV nitroglycerin may be considered as an adjunct to diuretic therapy for relief of dyspnea in patients hospitalized for acutely decompensated heart failure. IV nitroglycerin causes venodilation, which lowers preload and may help to rapidly reduce pulmonary congestion. Patients with heart failure and hypertension, coronary ischemia, or substantial mitral regurgitation are often considered ideal candidates for the use of IV nitroglycerin. However, tachyphylaxis to nitroglycerin may develop within 24 hours, and up to 20% of those with heart failure may have inadequate response to even high doses.
Chronic Anal Fissure
For topical (intra-anal) use of nitroglycerin 0.4% ointment in the treatment of chronic anal fissures,