Nitroglycerin comes as a sublingual tablet to take under the tongue. The tablets is usually taken as needed, either 5 to 10 minutes before activities that may cause attacks of angina or at the first sign of an attack. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take nitroglycerin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Nitroglycerin may not work as well after you have used it for some time or if you have taken many doses. Take the fewest tablets needed to relieve the pain of your attacks. If your angina attacks happen more often, last longer, or become more severe at any time during your treatment, call your doctor.

Talk to your doctor about how to use nitroglycerin tablets to treat angina attacks. Your doctor will probably tell you to sit down and take one dose of nitroglycerin when an attack begins. If your symptoms do not improve very much or if they worsen after you take this dose you may be told to call for emergency medical help right away. If your symptoms do not go away completely after you take the first dose, your doctor may tell you to take a second dose after 5 minutes have passed and a third dose 5 minutes after the second dose. Call for emergency medical help right away if your chest pain has not gone away completely 5 minutes after you take the third dose.

Do not chew, crush, or swallow nitroglycerin sublingual tablets. Instead, place the tablet under your tongue or between your cheek and gum and wait for it to dissolve. You may feel burning or tingling in your mouth as the tablet dissolves. This is normal but is not a sign that the tablet is working. Do not be concerned that the tablet is not working if you do not feel the burning or tingling.