When nitroglycerin is administered for angina, what physiological changes can be anticipated?

When nitroglycerin is administered for angina, one can anticipate several physiological changes primarily related to its vasodilatory effects. Nitroglycerin works by relaxing the smooth muscle in blood vessels, leading to vasodilation.

One significant effect of this vasodilation is the decrease in preload, which is the volume of blood in the ventricles at the end of diastole. Since nitroglycerin dilates the veins, it reduces the amount of blood returning to the heart, thereby decreasing preload. Lowering preload is beneficial in angina management as it reduces the workload on the heart, thereby alleviating angina symptoms.

Additionally, due to vasodilation, blood pressure tends to decrease. This drop in blood pressure occurs because dilating the veins decreases vascular resistance, allowing blood to flow more easily. Lower blood pressure can further help in reducing cardiac workload and oxygen demand, which is crucial in managing angina.

Consequently, the most accurate physiological changes to anticipate when administering nitroglycerin are a decrease in blood pressure and a decrease in preload. Thus, the correct choice encompasses both anticipated effects, specifically indicating that blood pressure will decrease while preload will also decrease.