Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Dizziness: Nitroglycerin may cause dizziness or a spinning sensation (vertigo), affecting your ability to drive or operate machinery. Avoid these and other hazardous tasks until you have determined how this medication affects you.
Low blood pressure: Headaches or symptoms of low blood pressure such as weakness or dizziness, particularly when getting up from a sitting or lying down position, may result from taking too much nitroglycerin. If these symptoms occur, your doctor may reduce the dose or stop the use of nitroglycerin. People who might be negatively affected by low blood pressure should use nitroglycerin sublingual tablets with caution. People who take diuretics or have preexisting low blood pressure may be at a greater risk of experiencing low blood pressure.
Medical conditions: The benefits and safety of nitroglycerin sublingual tablets for people who have an acute heart attack or congestive heart failure have not been established.
Tolerance: Nitroglycerin users may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also happen, especially if long-acting nitrates are used at the same time. As tolerance to nitroglycerin develops, the effect of fast-acting sublingual (under the tongue) nitroglycerin is somewhat reduced.
Pregnancy: This medication has not been studied for use by pregnant women and should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: It is not known if nitroglycerin sublingual passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
The safety and effectiveness of this medication for children have not been established.