From the Guidelines
Nitroglycerin is effective in decreasing pain in unstable angina, and patients should receive sublingual nitroglycerin (0.3 mg-0.4 mg) every 5 minutes for up to 3 doses, as recommended by the 2014 AHA/ACC guideline 1. When experiencing angina pain, patients should place one nitroglycerin tablet (0.3-0.6 mg) under the tongue and allow it to dissolve, which typically provides relief within 1-5 minutes. Some key points to consider when using nitroglycerin for unstable angina include:
- The dose can be repeated every 5 minutes for up to three doses, after which an assessment should be made about the need for intravenous nitroglycerin if not contraindicated 1.
- If chest pain continues after three doses, immediate medical attention should be sought as this may indicate a heart attack.
- Nitroglycerin works by dilating blood vessels, particularly coronary arteries, which improves blood flow to the heart muscle and reduces the oxygen demand of the heart, as explained in the 2007 ACC/AHA guidelines 1.
- This vasodilation effect helps resolve the temporary oxygen deficit that causes angina pain.
- Nitroglycerin is available in various forms including sublingual tablets, spray, and extended-release patches, with the sublingual form providing the quickest relief for acute angina episodes.
- Patients should store nitroglycerin properly in its original container, away from heat and moisture, and replace it every 6-12 months as it can lose potency over time.
From the FDA Drug Label
Nitroglycerin sublingual tablets can relieve this pain. Nitroglycerin is used to treat a type of chest pain called angina. One tablet should be dissolved under the tongue or in the oral cavity at the first sign of chest pain.
Nitroglycerin can decrease pain in unstable angina, as it is used to treat a type of chest pain called angina. The medication works by relieving the pain, and the dose may be repeated approximately every 5 minutes, until the chest pain is relieved 2, 2.
- Key points:
- Nitroglycerin is used to treat angina.
- Nitroglycerin can relieve chest pain.
- The dose may be repeated approximately every 5 minutes, until the chest pain is relieved.
From the Research
Nitroglycerin in Unstable Angina
- Nitroglycerin is used to relieve anginal pain in unstable angina, with studies showing its efficacy in this context 3, 4, 5.
- The administration of nitroglycerin can be through various routes, including intravenous and buccal, with both methods providing relief from anginal pain 3.
- The efficacy of nitroglycerin in reducing pain in unstable angina is supported by its ability to induce vasodilation and reduce ischemia 4, 5.
Mechanism and Effects
- Nitroglycerin works by forming S-nitroso-NAC, which induces vasodilation and inhibits platelet aggregation, thereby reducing the frequency of chest pain episodes 5.
- The combination of nitroglycerin with N-acetylcysteine (NAC) may augment the clinical efficacy of nitroglycerin by reducing the incidence of acute myocardial infarction 5.
- However, this combination may also increase the risk of symptomatic hypotension, suggesting the need for cautious use 5.
Clinical Use
- Nitroglycerin is a standard therapy in unstable angina, often used in conjunction with other medications such as beta-blockers, aspirin, and heparin 6, 4.
- The goal of treatment with nitroglycerin is to ameliorate symptoms, reduce ischemia, and prevent recurrent ischemia, myocardial infarction, and death 4.
- Long-term management of unstable angina may include the use of nitroglycerin, as well as other medications and lifestyle modifications to control risk factors and improve quality of life 7.