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.
Acute angina attacks: Nitroglycerin patches are not intended for immediate relief of acute attacks of angina. Sublingual (under the tongue) nitroglycerin preparations (spray or tablets) should be used for this purpose.
Dizziness/reduced alertness: People using this medication may experience faintness or dizziness and reduced reaction time when driving or operating machinery, especially at the start of treatment. Avoid these and other hazardous tasks until you have determined how this medication affects you.
Heart disease: The benefits and safety of using the nitroglycerin patch have not been established for people who have had an acute heart attack or have congestive heart failure.
Low blood pressure: Headaches or symptoms of low blood pressure such as weakness or dizziness, particularly when getting up suddenly 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 have you stop using the nitroglycerin patch. People who might be negatively affected by low blood pressure should use this medication with caution. If you take diuretics or have preexisting low blood pressure, you may be at an increased risk of experiencing this effect.
Symptom changes: If your symptoms of angina increase at any time (including during the period of the day that you aren't taking the medication), be sure to tell your doctor.
Tolerance: People who use nitroglycerin may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also happen, especially if a medication-free period is not observed each day. As tolerance to nitroglycerin patches develops, the effect of fast-acting sublingual (under the tongue) nitroglycerin is also somewhat reduced.
Pregnancy: This medication has not been studied for use by pregnant women. Be sure to tell your doctor if you are pregnant or planning to become pregnant. If you become pregnant while using this medication inform your doctor as soon as possible.
Breast-feeding: It is not known if nitroglycerin 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.
Children: The safety and effectiveness of this medication for children have not been established.