Nitroglycerin is used to prevent and treat angina (chest pain). Nitroglycerin is a vasodilator, which relaxes the muscles of the blood vessels, causing an increase in the oxygen supply to the heart.

The sublingual tablets and oral spray act quickly and can be used to relieve chest pain after it has started. The sustained-release tablets and capsules do not act quickly; they are used to prevent chest pain.

Nitroglycerin Facts
Brand names (manufacturers):
Nitrogard (Forest); nitroglycerin (various manufacturers); Nitroglyn (Kenwood); Nitrolingual (Horizon); Nitrong (Wharton); NitroQuick (Ethex); Nitrostat (Parke-Davis)

Type of drug: Antianginal

Ingredient: Nitroglycerin

Dosage forms: Sustained-release tablets (2.6 mg, 6.5 mg, and 9 mg); sustained-release capsules (2.5 mg, 6.5 mg, 9 mg, and 13 mg); sublingual tablets (0.3 mg, 0.4 mg, and 0.6 mg); buccal tablets, controlled release (1 mg, 2 mg, 2.5 mg, 3 mg, and 5 mg); oral spray (0.4 mg per dose)

Storage: Store the sustained-release tablets and capsules, the controlled-release buccal tablets, and the oral spray in tightly capped bottles in a cool, dry place. Keep the sublingual tablets in their original glass container. A small, temporary supply of tablets can also be stored in a stainless-steel container that is now available. The pendant-type container, which can be worn around your neck, is a convenient storage place for an emergency supply. Never store them in the refrigerator or the bathroom medicine cabinet, because the drug may lose its potency.

Treatment

Be sure to ask your doctor or pharmacist for complete instructions on how and when to use the specific type of nitroglycerin prescribed for you.

The sublingual form of nitroglycerin should never be chewed or swallowed. Place the sublingual tablet under the tongue and allow it to dissolve; the medicine is absorbed through the lining of the mouth.

The oral spray form of nitroglycerin is absorbed directly through the lining of the mouth. To use the spray, remove the plastic cover on the container. Then, without shaking the container, spray the medication onto or under the tongue. Try not to inhale the spray. Close your mouth after each spray, and try to avoid swallowing right away. Nitroglycerin spray loses its effectiveness if it is swallowed.

Take one sublingual tablet or one or two sprays at the first sign of chest pain. Sit down while you are waiting for the medicine to take effect. Do not eat, drink, or smoke while nitroglycerin is in your mouth. Try not to swallow while nitroglycerin is dissolving, and do not rinse your mouth afterward.

Sublingual nitroglycerin or nitroglycerin spray should start working in one to three minutes. If there
is no relief, take another tablet or spray dose in five minutes. IF YOU TAKE THREE TABLETS OR THREE SEPARATE SPRAY DOSES WITHOUT ANY SIGN OF IMPROVEMENT, CALL A DOCTOR IMMEDIATELY OR GO TO A HOSPITAL EMERGENCY ROOM. As a preventive measure, take a nitroglycerin sublingual tablet or a spray dose five or ten minutes before heavy exercise, exposure to high altitudes or extreme cold, or any other potentially stressful situation. Be sure to carry some nitroglycerin sublingual tablets or oral spray with you at ALL times.

The controlled-release buccal tablet form of nitroglycerin is absorbed directly through the lining of the mouth. NEVER chew or swallow the sublingual or buccal tablets. Place the buccal tablet between the upper lip and the gum on either side of the front teeth or between the cheek and the gum. The buccal tablet is held in place by a sticky gel seal that develops once the tablet is in contact with saliva. If you wear dentures, the buccal tablet can be placed anywhere between the cheek and the gum. Avoid drinking hot liquids or touching the buccal tablet with your tongue; this can cause the tablet to dissolve faster and could increase the risk of side effects. If the buccal tablet is swallowed by mistake, replace it with another tablet. Nitroglycerin buccal tablets lose their effectiveness when swallowed. Try not to take the buccal tablet at bedtime in order to avoid inadvertently swallowing and choking on the tablet while you are sleeping.

Take the sustained-release tablets or capsules with a full glass of water on an empty stomach one hour before or two hours after a meal. Swallow the sustained-release tablets and capsules whole. Chewing, crushing, or breaking them destroys their sustained-release activity and possibly increases the side effects. If you miss a dose of the sustained-release tablets or capsules, take the missed dose as soon as possible. However, if it is more than halfway through the interval between doses, do not take the missed dose at all; just return to your regular dosing schedule. Do not double the next dose of the sustained-release medication.

Side Effects

Minor: Dizziness, flushing of the face, headache, light-headedness, nausea, vomiting, or weakness. These side effects should diminish or disappear as your body adjusts to the medication.

If you feel dizzy or light-headed, sit or lie down for a while; get up slowly from a sitting or reclining position; and be careful on stairs. To avoid dizziness or light-headedness when you stand, contract and relax the muscles of your legs for a few moments before rising. Do this by pushing one foot against the floor while raising the other foot slightly, alternating feet so that you are "pumping" your legs in a pedaling motion.

Acetaminophen may help to relieve headaches caused by this medication.

Major: Tell your doctor about any side effects that are persistent or particularly bothersome. IT IS ESPECIALLY IMPORTANT TO TELL YOUR DOCTOR about diarrhea, fainting, palpitations, rash, or sweating.

Interactions

Nitroglycerin can interact with other types of medications:
  • The combination of alcohol and nitroglycerin can lead to dizziness and fainting.

  • Nitroglycerin can increase the side effects of the tricyclic antidepressants.

  • Do not use sildenafil (Viagra) with nitroglycerin. The use of this combination may cause serious side effects, even death.
Before starting to take nitroglycerin, BE SURE TO TELL YOUR DOCTOR about any medications you are currently taking, especially tricyclic antidepressants (such as imipramine, desipramine, amitriptyline, and doxepin).

Warnings
  • Tell your doctor about unusual or allergic reactions you have had to any medications, especially to nitroglycerin or isosorbide dinitrate.

  • Before starting to take this medication, be sure to tell your doctor if you now have or ever had anemia, glaucoma, a head injury, low blood pressure, or thyroid disease or if you have recently had a heart attack.

  • If this drug makes you dizzy or light-headed, do not take part in any activity that requires alertness, such as driving a car or operating potentially dangerous machinery.

  • Before surgery or other medical or dental treatment, tell your doctor or dentist you are taking this drug.

  • Tolerance may develop to this medication within one to three months. If it seems to lose its effectiveness, contact your doctor.

  • You should not discontinue use of nitroglycerin (if you have been taking it on a regular basis) unless you first consult your doctor. Stopping it abruptly may lead to further chest pain. Your doctor may therefore want to decrease your dosage gradually.

  • If you have frequent diarrhea, you may not be absorbing the sustained-release form of this medication. Discuss this with your doctor.

  • While taking this medication, do not take any over-the-counter (nonprescription) asthma, allergy, sinus, cough, cold, or diet preparations unless you first check with your doctor or pharmacist. Some of these decrease the effectiveness of nitroglycerin.

  • The cotton plug should be removed when the bottle is first opened; it should not be replaced. The cotton plug absorbs some of the medication, decreasing its potency.

  • Nitroglycerin is highly flammable. Do not use it in places where it might be ignited.

  • Be sure to tell your doctor if you are pregnant. Although the systemic form of nitroglycerin appears to be safe, extensive studies in pregnant women have not been conducted. Also tell your doctor if you are breast-feeding an infant. It is not known whether nitroglycerin passes into breast milk.