Chronic Stable Angina
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 chronic stable angina. 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 (MI), 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.
Non-ST-Segment-Elevation Acute Coronary Syndromes
Nitroglycerin is used in the management of non-ST-segment-elevation acute coronary syndromes (NSTE ACS). Patients with NSTE ACS have either unstable angina or non-ST-segment-elevation MI (NSTEMI); because these conditions are part of a continuum of acute myocardial ischemia and have indistinguishable clinical features upon presentation, the same initial treatment strategies are recommended. The American Heart Association/American College of Cardiology (AHA/ACC) guideline for the management of patients with NSTE ACS recommends sublingual nitroglycerin (0.3-0.4 mg every 5 minutes for up to 3 doses) for the relief of ongoing ischemic pain in patients with NSTE ACS; IV nitroglycerin may be used in patients with persistent ischemia who do not respond to sublingual therapy and administration of a β-blocker or those with heart failure or hypertension.
Acute Myocardial Infarction
Nitroglycerin is used in the management of acute MI, generally in patients with hypertension or heart failure. Sublingual nitroglycerin has been administered for the initial relief of ischemic discomfort in patients with acute MI. However, the manufacturer states that the benefits of sublingual nitroglycerin in patients with acute MI have not been established; if the drug is used in this setting, careful hemodynamic and clinical monitoring is essential because of the possibility of hypotension and tachycardia. IV nitroglycerin may be used in patients with acute MI who have ongoing chest pain, hypertension, or heart failure. In addition to potentially alleviating ischemic myocardial pain, beneficial hemodynamic effects of nitroglycerin include vasodilation of the coronary arteries (especially at or near the site of recent plaque disruption), peripheral arteries, and venous capacitance vessels; however, the drug generally does not reduce myocardial injury associated with epicardial coronary artery occlusion unless there is substantial vasospasm. Although studies conducted prior to the routine use of reperfusion therapy suggested a mortality benefit with nitrates in patients with acute MI, this benefit was not confirmed in 2 large randomized controlled studies.
The American College of Cardiology Foundation/American Heart Association (ACCF/AHA) guideline for the management of STEMI states that IV nitroglycerin may be beneficial in patients with STEMI and heart failure or hypertension. These experts state that there is no role for the routine use of oral nitrates during the convalescent phase of STEMI.
For recommendations on the management of NSTEMI, see Uses: Non-ST-Segment-Elevation Acute Coronary Syndromes.For precautions associated with the use of nitroglycerin in patients with acute MI, 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 MI. 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,