Some nitroglycerin medications are taken to help prevent angina attacks, while others are taken at the first sign of angina attacks. While taking nitroglycerin during an angina attack, you should avoid eating, drinking, smoking, or chewing tobacco. You should also avoid chewing or crushing a tablet that should be swallowed. Similarly, a tablet you put under your tongue will be absorbed more quickly when allowed to dissolve in your mouth, so do not crush it, chew it, or swallow it. For safety purposes, avoid standing when taking nitroglycerin. Make sure you sit down just in case you feel dizzy to avoid falling. Never store other medications with nitroglycerin. Keep air away from the medication by keeping the container tightly closed.