Which of the following is a common adverse effect of nitroglycerin?

Nitroglycerin, commonly used in the management of angina and other cardiac conditions, often leads to the development of headaches in patients. This is primarily due to its mechanism of action as a vasodilator; it relaxes and dilates blood vessels, which can increase blood flow to the brain and trigger headaches. These headaches are generally considered a common and expected side effect, typically occurring when the medication is first initiated or when doses are increased.

While other options may have their own significance in pharmacology, they are not commonly associated with nitroglycerin use. Bradycardia, for example, is more often linked to other cardiac medications rather than nitroglycerin. Insomnia and hyperglycemia also do not have direct associations with nitroglycerin therapy, further highlighting the specificity of headache as a pertinent adverse effect in this context.