Nitroglycerin can be taken as prescribed by a physician in cases of coronary angina and congestive heart failure. Nitroglycerin is used for the treatment and prevention of coronary angina, and may also be used to lower blood pressure or to treat congestive heart failure; therefore, nitroglycerin may be taken under the direction of a physician in the presence of the foregoing. ADVERSE REACTIONS: Vasodilatory headache may occur, and occasionally vertigo, weakness, palpitations, and other postural hypotension may occur, especially in upright and braked patients. Contraindications: It is contraindicated in patients with acute circulatory failure, severe hypotension, acute myocardial infarction with low filling pressures, hypertrophic obstructive cardiomyopathy, constrictive pericarditis, severe anemia, glaucoma, elevated intracranial pressure, and nitrocompound hypersensitivity. Precautions: the smallest dose that is effective in relieving acute angina should be used; overdose may lead to tolerance; severe hypotension may occur with small doses, especially in the upright position, and when taking the drug sublingually, the patient should be seated as much as possible to avoid falling due to dizziness. The specific circumstances of the use of the drug must be consulted with a medical professional, under the guidance of the doctor to use the drug.