After administering his third nitroglycerin tablet, a patient complains of dizziness and sweating. What should you suspect?

The correct answer highlights the physiological effects of nitroglycerin, which is primarily a vasodilator. When nitroglycerin is administered, it acts to dilate blood vessels, notably in the coronary arteries, thereby reducing the workload on the heart and alleviating angina. However, excessive vasodilation can lead to a significant decrease in blood pressure, resulting in symptoms such as dizziness and sweating.

In this case, the patient's complaints of dizziness and sweating indicate that there may be an insufficient blood flow or perfusion to the brain and other vital organs due to the lowering of systemic vascular resistance and blood pressure from the nitroglycerin. Therefore, it is crucial to recognize that the administration of nitroglycerin can have profound effects on blood circulation, and these symptoms are likely due to its vasodilatory effects leading to decreased perfusion rather than indicating an alternate diagnosis like an overdose or dehydration.

Understanding that vasodilation from nitroglycerin can lead to hypotension is key in distinguishing the physiological basis of the patient's symptoms and optimizing further patient management.