Why can't you take nitroglycerin orally?

Answer 1

Nitroglycerin cannot be taken orally because it undergoes significant first-pass metabolism in the liver, where much of the drug is broken down before it can enter the bloodstream and exert its effects. This results in a very low bioavailability when taken by mouth, making it ineffective for treating conditions like angina. Instead, nitroglycerin is typically administered sublingually, transdermally, or intravenously to bypass this metabolic process and ensure rapid action.