What are the indications for nitroglycerin (glyceryl trinitrate) for managing hypertension?

From the Guidelines

Nitroglycerin is indicated for the management of acute hypertension or ischemic pain in patients with acute coronary syndromes (ACS), particularly in those with ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation ACS, as it can help relieve symptoms of ischemia and pulmonary congestion, although it does not have a significant effect on outcomes 1. The primary use of nitroglycerin in the context of blood pressure management is for the relief of ischemic pain or acute hypertension in patients with ACS, as well as for managing pulmonary congestion.

• The medication is typically administered via the sublingual route initially, which can be followed by intravenous or topical administration of nitroglycerin or oral administration of longer-acting nitrate preparations 1.
• It is essential to monitor patients treated with nitrates for potential adverse effects, particularly profound hypotension, which can exacerbate ischemia, and to be cautious in patients at increased risk, such as the elderly, those who are volume depleted, or those who have used sildenafil within 24 hours or tadalafil within 48 hours 1.
• Nitrate tolerance is a concern even within the first 24 hours, and efforts should be made to minimize this by reducing intravenous doses and implementing intermittent dosing by nonintravenous routes once the patient is stable from an ischemic standpoint 1. The ACC/AHA guidelines recommend the use of nitroglycerin to relieve ischemic pain or acute hypertension, or to manage pulmonary congestion, at a Level of Evidence C, but caution against using it at the expense of agents with proven benefits on outcomes, such as β-blockers or ACE inhibitors, particularly in the convalescent stage 1.
• The guidelines also note that nitrates should be used with caution in patients with inferior STEMI and are contraindicated if right ventricular infarction is present due to their effects on lowering preload 1.

From the FDA Drug Label

INDICATIONS & USAGE Nitroglycerin Injection is indicated for treatment of peri-operative hypertension; for control of congestive heart failure in the setting of acute myocardial infarction; for treatment of angina pectoris in patients who have not responded to sublingual nitroglycerin and β-blockers; and for induction of intraoperative hypotension. The indications for nitroglycerine for blood pressure are:

• Peri-operative hypertension
• Induction of intraoperative hypotension 2

From the Research

Indications for Nitroglycerine

• Nitroglycerine is used to manage hypertensive emergencies and urgencies, particularly in patients with acute target-organ damage 3.
• It is also used to treat angina, acute coronary syndromes, acute heart failure, pulmonary edema, and aortic dissection 4.
• Topical nitroglycerin ointment can be used to treat acute hypertension in hospitalized inpatients, although it is not approved by the Food and Drug Administration for this condition 5.
• Intravenous nitroglycerin is used in the management of acute decompensated heart failure, reducing LV and RV filling pressures and afterload 6.

Mechanism of Action and Effects

• Nitroglycerine is converted to nitric oxide in the body, leading to venodilation at lower dosages and arteriodilation at higher dosages, resulting in both preload and afterload reduction 4.
• It has a rapid onset of action and short half-life, making it a useful treatment for acute conditions 6.
• Nitroglycerine can reduce mortality and heart failure hospitalizations in patients with heart failure due to left ventricular systolic dysfunction, particularly when combined with hydralazine, beta-blockers, and angiotensin-converting enzyme (ACE) inhibitors 7.

Contraindications and Side Effects

• Common side effects of nitroglycerine include headache, hypotension, and dizziness 7.
• Severe headaches and/or symptomatic hypotension may necessitate discontinuation of nitrate therapy 7.
• Nitroglycerine should be used with caution in patients with acute inferior myocardial infarction associated with right ventricular dysfunction or infarction, or with concomitant use of phosphodiesterase-5 inhibitors or N-acetylcysteine 7.