From the Guidelines
Nitroglycerin should be used with extreme caution in patients with inferior ST-elevation myocardial infarction (STEMI) and is generally not recommended as first-line therapy. When treating inferior STEMI, clinicians should first assess for right ventricular involvement, as these patients are particularly vulnerable to hypotension with nitroglycerin 1. If nitroglycerin is deemed necessary for ongoing chest pain or hypertension, it should be administered at low doses (starting at 0.4 mg sublingual or 5-10 mcg/min IV) with careful blood pressure monitoring. Prior to administration, establish IV access, ensure systolic blood pressure is above 100 mmHg, and avoid use in patients who have recently taken phosphodiesterase-5 inhibitors 1. The caution with nitroglycerin in inferior STEMI stems from its vasodilatory effect, which reduces preload—a mechanism that can precipitate severe hypotension in patients with right ventricular infarction, who are dependent on adequate preload to maintain cardiac output.
Some key considerations when using nitroglycerin in this context include:
- Monitoring for potential adverse effects, particularly profound hypotension, which can exacerbate ischemia 1
- Avoiding use in patients with right ventricular infarction, as nitrates can worsen outcomes in these patients 1
- Using alternative therapies, such as morphine, for pain control, and prioritizing antiplatelet therapy and rapid reperfusion strategies 1
- Being aware of the potential for nitrate tolerance, even within the first 24 hours, and taking steps to minimize this by reducing intravenous doses and implementing intermittent dosing by nonintravenous routes once the patient is stable from an ischemic standpoint 1
From the FDA Drug Label
CONTRAINDICATIONS Nitroglycerin sublingual tablets are contraindicated in patients who are allergic to it. Sublingual nitroglycerin therapy is contraindicated in patients with early myocardial infarction, severe anemia, increased intracranial pressure, and those with a known hypersensitivity to nitroglycerin. WARNINGS The benefits of sublingual nitroglycerin in patients with acute myocardial infarction or congestive heart failure have not been established. If one elects to use nitroglycerin in these conditions, careful clinical or hemodynamic monitoring must be used because of the possibility of hypotension and tachycardia.
Nitroglycerin is contraindicated in patients with early myocardial infarction. Therefore, it should not be given for an inferior ST-elevation myocardial infarction (STEMI) due to the risk of hypotension and tachycardia. Key considerations include:
From the Research
Nitroglycerin Administration in Inferior STEMI
- Nitroglycerin can be given for an inferior ST-elevation myocardial infarction (STEMI), but its administration should be done with caution, especially in patients with right ventricular involvement 3.
- A study published in 1989 found that up to 60% of patients with inferior wall acute myocardial infarction (AMI) develop hypotension, and in many cases, profound hypotension is precipitated by the administration of nitroglycerin 3.
- However, a more recent study published in 2016 found that nitroglycerin administration to patients with chest pain and inferior STEMI on their computer-interpreted electrocardiogram is not associated with a higher rate of hypotension compared to patients with STEMI in other territories 4.
- Another study published in 2019 found that field nitroglycerin did not result in a clinically significant decrease in blood pressure when compared with patients who did not receive nitroglycerin, but it did cause a clinically significant reduction in pain 5.
- The decision to administer nitroglycerin in inferior STEMI should be based on individual patient assessment, taking into account the potential benefits and risks, including the risk of hypotension and right ventricular involvement 3, 4, 5.
- It is also important to note that the localization of the culprit artery in inferior STEMI can be predicted by comparing ST elevation in leads II and III on the ECG, which can guide intervention 6.
- Intravenous nitroglycerin has been shown to be effective and safe for the treatment of cardiac failure in patients with acute myocardial infarction, including those with inferior infarction 7.