When you begin to feel an attack of angina starting (chest pains, tightness or squeezing in the chest), sit down. The oral spray, sublingual powder, and sublingual tablets work quickly to stop an angina attack that has already started or they can be used to prevent angina if you plan to exercise or expect a stressful event. The extended-release capsules are used every day on a specific schedule to prevent angina attacks. Nitroglycerin is available as two types of products that are used for different reasons. Ask your doctor if you have any questions. Read and follow the instructions in the insert carefully. This medicine comes with a patient information insert.