A patient with angina is prescribed nitroglycerin (NTG). Which of the following is the most common side effect?

Correct option is A

Vasodilation caused by nitroglycerin leads to pulsatile headache due to meningeal vessel dilation; this is the most common side effect.
Explanation of options: (a) ✔ Correct; headache is the hallmark side effect. (b) ✘ Reflex tachycardia, not bradycardia, is more likely. (c) ✘ Constipation is seen with opioids, not NTG. (d) ✘ Tinnitus is unrelated to NTG therapy.