What is an indication for using nitroglycerin?

Nitroglycerin is primarily indicated for the relief of chest pain that is suggestive of angina, which is typically associated with coronary artery disease. Angina occurs when the heart muscle does not receive enough oxygen-rich blood, and nitroglycerin works as a vasodilator. This means it relaxes and widens the blood vessels, leading to improved blood flow to the heart muscle. By alleviating the pressure and discomfort associated with angina, nitroglycerin helps reduce symptoms and can prevent more severe cardiac events.

In context to other options, severe headache is not an indication for nitroglycerin; it can actually be a side effect of this medication due to its vasodilatory effects. Low blood sugar is treated with glucose rather than nitroglycerin. High blood pressure can have a complex relationship with nitroglycerin; while it may lower blood pressure due to its vasodilatory properties, it is not specifically indicated for treating hypertension. Rather, it is used in the context of managing cardiac conditions, particularly associated with chest pain.