Final answer:
Sublingual nitroglycerin differs from orally administered isosorbide mononitrate in its duration of action, with nitroglycerin having a shorter duration and isosorbide mononitrate having a longer-lasting effect.
Step-by-step explanation:
Sublingual nitroglycerin differs from isosorbide mononitrate given orally in duration of action. Nitroglycerin is administered sublingually and works rapidly by releasing nitric oxide, which acts as a potent vasodilator but has a short duration of action. Isosorbide mononitrate, on the other hand, has a longer duration of action when given orally, which makes it suitable for long-term management of chronic stable angina. Both drugs work by similar mechanisms to relieve angina, but their effects on heart rate and postural blood pressure are not significantly different to be the distinguishing factor between the two.