Nitrates

What are nitrates used for?

Nitrates are medicines that are used to prevent and relieve chest pain (angina) due to coronary artery disease. They belong to a class of medications called vasodilators that cause blood vessels to widen. The most common types of nitrates are nitroglycerin (glyceryl trinitrate or GTN), isosorbide dinitrate, and isosorbide mononitrate. Nitrates can be used to treat angina in three ways:

  • Short-term nitrates are taken to relieve angina on an as-needed basis
  • Short-term nitrates are also taken right before activities known to cause an attack to prevent angina
  • Long-term nitrates are taken daily to decrease the number of angina attacks

How do nitrates work?

Heart-related chest pain occurs when the heart muscle doesn’t get as much oxygen as it needs. This is usually due to narrowing of the arteries that supply blood to the heart, which is caused by atherosclerosis – the buildup of fatty plaque on the lining of the arteries. Nitrates work by relaxing and widening the blood vessels in the body, allowing more blood and oxygen to flow to the heart. Since the arteries are wider, it is easier for the heart to pump blood, so it does not require as much blood and oxygen.

What is nitrate tolerance?

If you have nitrate in your bloodstream all the time, your body grows accustomed to it and the medicine will lose its ability to dilate your blood vessels and therefore its ability to prevent or relieve angina. This loss of effectiveness is called nitrate tolerance. Nitrate tolerance is not a problem for patients taking short-acting nitrates, which are only in your bloodstream for a short time. However, patients taking long-acting nitrates need to have periods during each day where there are no nitrates in the body, and this is why your medicine may be prescribed to be taken at irregular intervals throughout the day.

How are nitrates taken?

Nitrate medications come in many forms. Short-term nitrates that are used on an as-needed basis for chest pain mainly come in sublingual (under the tongue) tablets, chewable tablets, and sprays. Long-term nitrates that are taken every day to prevent chest pain come as a pill, skin patch, or ointment. Different kinds may be combined to give you the best possible relief. If you are hospitalized for chest pain or a heart procedure, you may also receive liquid nitrates through an IV.

Nitroglycerin tablets, a form of short-term nitrates, are absorbed quickly into the bloodstream when they dissolve under the tongue, and should ease chest pain within 1 to 5 minutes. If you are taking short-term nitrates to prevent an anticipated attack, placing a tablet under the tongue 10 minutes before the activity will prevent angina for about an hour. If you are taking long-term nitrates, you may need to take them at uneven intervals throughout the day to prevent nitrate tolerance.

How should I store my nitrate medication?

Nitrates, particularly sublingual nitroglycerin tablets, may not work as well as they should if they are exposed to heat, moisture, or air for long periods of time. You can’t tell if a tablet is working based on a tingling or burning sensation under your tongue or flushing or warmth in your face and neck – not everyone feels these effects and some newer types of tablets don’t cause them at all. The only way to be sure your pills are working is to keep them dry in a closed bottle and be sure to throw out medication that has expired.

Nitroglycerin tablets are the least stable form of nitrates and typically need to be replaced every 3 to 6 months. Other types of nitrates such as spray nitroglycerin are not as easily ruined and can last longer. Be sure to check the expiration date on the bottle and refill your prescription before the medication expires.

Nitrates for Chronic Stable Angina

Chronic stable angina is chest pain that occurs in a predictable pattern, usually triggered by physical exertion or emotional stress. All men and women with chronic stable angina should receive nitroglycerin (sublingual tablet or spray) to relieve chest pain when it occurs, and to be taken before activities known to cause chest pain. If you have attacks of chest pain very often, you may be prescribed a long-term nitrate.

Nitrates may also be given to people with chronic stable angina to reduce the risk of death and heart attack, but these benefits have not been fully proven. In patients with high blood pressure or who have had a heart attack, nitrates should not be used to prevent heart attack and death because other types of medications have been proven to work better. In these patients, nitrates may still be taken to relieve chest pain if needed.

Nitrates are often combined with beta blockers or calcium channel blockers in patients who continue to have chest pain despite taking long-term nitrates or who get chest pain during the daily nitrate-free interval.

Nitrates for Unstable Angina & Mild Heart Attack

Unstable angina is chest pain that is unpredictable and may occur at rest. Men and women who have unstable angina or a mild heart attack are usually given IV nitroglycerin when they get to the hospital and then switched to tablet, ointment, or skin patch nitrates when their condition is stable. These patients should receive sublingual nitroglycerin (tablets or spray) when they leave the hospital to be used to relieve chest pain as needed. Some patients may also receive long-term nitrates to prevent chest pain. It is not known if nitrates reduce the risk of death or heart attack in people with unstable angina or mild heart attack. Nitrates can also relieve chest pain due to Prinzmetal’s Angina and Syndrome X.

Nitrates after A Severe Heart Attack

Fast-acting nitroglycerin tablets or spray can be used as needed for relief of chest pain in patients who have had a severe heart attack. However, continuous treatment with long-term nitrates is not recommended after a severe heart attack since they may actually increase the risk of death and other heart problems. There is no evidence that women and men treated with nitrates after a heart attack fare differently, but very few studies have analyzed results specifically in women.

Are women less likely than men to receive nitrates?

In a large study of patients with unstable angina or a mild heart attack (49% women), women were less likely than men to receive IV nitroglycerin while in the hospital but were just as likely to receive nitroglycerin tablets when they left the hospital. Since women in this study were less likely to suffer a heart attack or die than men despite receiving less IV nitroglycerin, this gender difference does not seem to have hurt women’s outcomes. Women and men undergoing bypass surgery or angioplasty are equally likely to receive nitrates.

What are the possible side effects of nitrates?

The most common side effects of nitrates are a throbbing headache (in about 50% of people), warmness and flushing of the skin, and dizziness or lightheadedness. These side effects are not serious and usually become less severe with continued use of the medication. If the headache persists, ask your doctor if you can take aspirin, acetaminophen (Tylenol), or ibuprofen (Advil, Motrin). Other possible non-serious side effects include a fast pulse, restlessness, and nausea or vomiting. Nitrate skin patches may cause skin irritation, which can be avoided by putting the patch in a different place each time.

Rarely, more serious side effects can occur when taking nitrates. Let your doctor know as soon as possible if you have any of these symptoms:

  • blurred vision
  • dryness of mouth
  • severe or prolonged headache
  • skin rash
  • blue-colored lips, fingernails, or palms
  • extreme dizziness or fainting
  • shortness of breath
  • weak and fast heartbeat
  • fever
  • convulsions

Prescribed Nitrates

Vasodilators – Coronary Vasodilators Nitroglycerin
(check with manufacturer for specific information on each drug)

Brands:

Nitro-Dur

Nitrostat

Nitrolingual Pumpspray

How is it given:

  • Oral (pill or tablet) or skin patch

What is it used for:

  • Prevention of chest pain (angina) due to coronary artery disease
  • Acute relief of an attack of angina due to coronary artery disease

You should not be treated with it if:

Possible Side Effects:

  • Headache, rapid pulse, flushing, sweating

Pregnancy/Nursing:

  • The safety of nitrates during pregnancy and nursing is unknown.

 

Vasodilators – Coronary Vasodilators Isosorbide Mononitrate
(check with manufacturer for specific information on each drug)

Brands:

IMDUR

Monoket

How is it given:

  • Pill or spray

What is it used for:

  • Prevention of chest pain (angina) due to coronary artery disease
  • Acute relief of an attack of angina pectoris due to coronary artery disease

You should not be treated with it if:

Possible Side Effects:

  • Headache, dizziness, lightheadedness, nausea, vomiting

Pregnancy/Nursing:

  • The safety of nitrates during pregnancy and nursing is unknown.

 

Vasodilators – Coronary Vasodilators Isosorbide Dinitrate
(check with manufacturer for specific information on each drug)

Brands:

Dilatrate

Isordil

Sorbitrate

How is it given:

  • Pill or spray

What is it used for:

  • Prevention of chest pain (angina) due to coronary artery disease
  • Acute relief of an attack of angina pectoris due to coronary artery disease

You should not be treated with it if:

Possible Side Effects:

  • Headache, dizziness, lightheadedness, nausea, vomiting

Pregnancy/Nursing:

  • The safety of nitrates during pregnancy and nursing is unknown.

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