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 ointment is 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 attacks: Not enough information exists on the safety of using nitroglycerin ointment during the early phase of a heart attack. If you suspect you are having a heart attack, call 9-1-1.
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 stop the use of nitroglycerin. People who might be negatively affected by low blood pressure should use nitroglycerin ointment with caution. People who take diuretics or have preexisting low blood pressure may be at more risk of being negatively affected.
PDE-5 inhibitors: PDE-5 inhibitors (e.g. sildenafil, tadalafil, vardenafil) should never be taken with nitroglycerin. Blood pressure may suddenly drop to life-threatening levels if these medications are combined. They may cause dizziness, fainting spells, heart attack, or stroke.
Tolerance: People taking nitroglycerin may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also develop, especially if a medication-free period is not observed each day.
Withdrawal: Dependence may occur with chronic use. To avoid possible withdrawal effects, reduce nitroglycerin ointment use gradually over 4 to 6 weeks.
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.
Breast-feeding: It is not known if this medication passes into breast milk. Be sure to discuss with your doctor the risks and benefits of using this medication before breast-feeding.
Children: The safety and effectiveness of this medication for children have not been established.