How quickly does nitroglycerin act when used to treat a myocardial infarction, i.e. when given in tablet form?

Does not treat: Nitroglycerin does not 'treat' a myocardial infarction. We use nitroglycerine IV in hospital for patients with chest pain. In my opinion sublingual nitroglycerine can at times delay diagnosis of a heart attack or severe heart problems because patients may not seek medical attention if suffering from recurrent chest pain relieved by nitroglycerine. Its like putting gel on a tooth with an abscess.

Almost immediately : Nitroglycerin given under the tongue is very rapidly absorbed into the blood stream. It can begin to work within 30 - 60 seconds to relieve chest pain and increase blood flow to the heart. Taking Nitroglycerin during a suspected heart attack should not delay calling 911 however.