Use nitroglycerin exactly as directed by your doctor. It will work only if applied correctly.

The ointment and transdermal forms of nitroglycerin are used to reduce the number of angina attacks. They will not relieve an attack that has already started because they work too slowly. Check with your doctor if you need a fast-acting medicine to relieve the pain of an angina attack.

This medicine usually comes with patient instructions. Read them carefully before using this medicine.

For patients using the ointment form of this medicine:

• Before applying a new dose of ointment, remove any ointment remaining on the skin from a previous dose. This will allow the fresh ointment to release the nitroglycerin properly.
• This medicine comes with dose-measuring papers. Use them to measure the length of ointment squeezed from the tube and to apply the ointment to the skin. Do not rub or massage the ointment into the skin; just spread in a thin, even layer, covering an area of the same size each time it is applied.
• Apply the ointment to skin that has little or no hair.
• Apply each dose of ointment to a different area of skin to prevent irritation or other skin problems.
• If your doctor has ordered an occlusive dressing (airtight covering, such as kitchen plastic wrap) to be applied over this medicine, make sure you know how to apply it. Since occlusive dressings increase the amount of medicine absorbed through the skin and the possibility of side effects, use them only as directed. If you have any questions about this, check with your health care professional.

For patients using the transdermal (stick-on patch) system:

• Do not try to trim or cut the adhesive patch to adjust the dosage. Check with your doctor if you think the medicine is not working as it should.
• Apply the patch to a clean, dry skin area with little or no hair and free of scars, cuts, or irritation. Remove the previous patch before applying a new one.
• Apply a new patch if the first one becomes loose or falls off.
• Apply each dose to a different area of skin to prevent skin irritation or other problems.

Dosing

The dose of nitroglycerin will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of nitrates. If your dose is different, do not change it unless your doctor tells you to do so.

For nitroglycerin
• For angina (chest pain):
  • For ointment dosage form:
    • Adults 15 to 30 milligrams (mg) (about one to two inches of ointment squeezed from tube) every six to eight hours.
    • Children Use and dose must be determined by your doctor.
  • For transdermal system (skin patch) dosage form:
    • Adults Apply one transdermal dosage system (skin patch) to intact skin once a day. The patch is usually left on for 12 to 14 hours a day and then taken off. Follow your doctor's instructions for when to put on and take off the skin patch.
    • Children Use and dose must be determined by your doctor.

Missed dose

• For patients using the ointment form of this medicine: If you miss a dose of this medicine, apply it as soon as possible unless the next scheduled dose is within 2 hours. Then go back to your regular dosing schedule. Do not increase the amount used.
• For patients using the transdermal (stick-on patch) system: If you miss a dose of this medicine, apply it as soon as possible. Then go back to your regular dosing schedule.

Storage

• To store the ointment form of this medicine:
  • Keep out of the reach of children.
  • Store the tube of nitroglycerin ointment in a cool place and keep it tightly closed.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.
• To store the transdermal (stick-on patch) system :
  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For nitroglycerin applied to the skin, the following should be considered:

Allergies Tell your doctor if you have ever had any unusual or allergic reaction to nitrates or nitrites. Also tell your health care professional if you are allergic to any other substances, such as certain foods, preservatives, or dyes.

Pregnancy Nitrates have not been studied in pregnant women. Before taking these medicines, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding It is not known whether this medicine passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are taking these medicines and who wish to breast-feed should discuss this with their doctor.

Children Studies on these medicines have been done only in adult patients, and there is no specific information comparing use of nitrates in children with use in other age groups.

Older adults Dizziness or lightheadedness may be more likely to occur in the elderly, who may be more sensitive to the effects of nitrates.

Other medicines Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are using nitroglycerin, it is especially important that your health care professional know if you are taking any of the following:

• Antihypertensives (high blood pressure medicine) or
• Other heart medicine May increase the effects of nitroglycerin on blood pressure

• Sildenafil (e.g., Viagra) or
• Tadalafil (e.g., Cialis) or
• Vardenafil (e.g., Levitra) These medicines which treat sexual impotence be used together with nitrates. You should tell your doctor right away if you are taking one of these drugs.

• Anemia (severe)

• Glaucoma May be worsened by nitroglycerin

• Head injury (recent) or
• Stroke (recent) Nitroglycerin may increase pressure in the brain, which can make problems worse

• Heart attack (recent) Nitroglycerin may lower blood pressure, which can aggravate problems associated with heart attack

• Kidney disease or
• Liver disease Effects may be increased because of slower removal of nitroglycerin from the body

• Overactive thyroid