Harvard Heart Letter

Take nitroglycerin to ease-and avoid-a common heart disease symptom

Take nitroglycerin to ease—and avoid—a common heart disease symptom

Discovered more than 150 years ago, this drug comes in a variety of formulations. Does one make sense for you?

If your heart's arteries are choked with cholesterol-filled plaque, a sudden increase in the heart's demand for oxygen-rich blood from physical exertion or emotional stress can trigger the chest pain known as angina. But a tiny tablet of nitroglycerin often relieves the pain within minutes.

Nitroglycerin is underused

Nitroglycerin and related drugs, known as nitrates, widen the arteries that nourish the heart and reduce the heart's workload. Under-the-tongue (sublingual) nitroglycerin tablets are perhaps the best-known version of this common medication. But nitrates come in a variety of different formulations (see "Nitrates for angina: Many choices").

"My personal view is that these medications are seriously underused. Nitrates have substantial benefits both for chronic stable coronary disease and for heart failure," says Dr. James Januzzi, professor of medicine at Harvard Medical School and director of the cardiac intensive care unit at Massachusetts General Hospital. Nitrates can help treat and prevent bouts of angina and reduce the overall number of attacks, he says. And people with heart failure may reap additional benefits. For instance, by expanding large veins in the legs and lungs, nitrates lower the amount of blood returning to the heart, easing fluid buildup in the lungs and combating shortness of breath.

Short-acting tablets and sprays

Short-acting nitroglycerin also comes in a spray version that you spritz under your tongue. If you have arthritis in your hands or a dry mouth, it may be easier to use than pills. Both the pill and spray versions are equally effective and cause a sweet, tingling sensation—a sign the drug is working.

Be sure to carry the medication with you at all times. Some people use a metal vial on a necklace to carry their pills. The tablets are sensitive to air, light, and heat, so recap your bottle quickly and store it in a cool, dry place like a drawer. Once you open a bottle, the tablets are good for only a month or two, says Dr. Januzzi. The spray has a shelf life of two to three years.

If you have one or fewer angina episodes per week, short-acting nitroglycerin makes the most sense. You can also take a dose right before activity that could cause angina, such as mowing the lawn, playing sports, or walking up a hill (especially in the cold).

Nitroglycerin comes in a spray as well as a pill form.

Long-acting pills or patches

If you have two or more angina episodes per week, a long-acting nitrate is a better bet. Long-acting nitrates are taken as capsules or tablets or delivered through a skin patch.

The body can develop tolerance to these drugs, so you need a nitrate-free period that lasts several hours at least once a day, says Dr. Januzzi. "I usually tell people with frequent angina to take extended-release tablets twice a day, then stay off the drug at night," he says. In contrast, a person with heart failure who is short of breath overnight may do better taking the drug at night.

Headaches are a common side effect of nitrates, but they usually don't last long. If you take long-acting nitrates, the headaches usually stop within a week or so, after your body adapts. Dizziness can also occur, which is why doctors always recommend sitting down when taking a dose and for a few minutes afterward. Men who take erectile dysfunction drugs such as Viagra, Levitra, Cialis, and Stendra must never take any form of nitrate, unless they are in a medical setting where they can be watched closely. That's because the combination can lead to a severe and possibly fatal drop in blood pressure. 

Nitrates for angina: Many choices

SHORT- ACTING

Formulation (examples of brands)

How taken

How often

How fast

How long

nitroglycerin tablet (Nitrolingual, Nitrostat)

Dissolved under the tongue

As needed for angina,

up to three doses, one

every five minutes *

2 to 5 minutes

15 to 30

minutes

nitroglycerin spray

(Nitrolingual Pumpspray, Nitromist)

Sprayed under the tongue

LONG-LASTING

buccal nitroglycerin

(Nitrogard)

Placed under the upper lip or

between the cheek and gum

Before an event likely

to cause angina

5 to 10

minutes

3 to 5 hours

isosorbide dinitrate (ISDN) tablet

(Isordil)

Swallowed whole

Two to three times per day

15 to 30

minutes

3 to 6 hours

isosorbide-5 mononitrate (ISMN) tablet

(Imdur, Ismo)

Once a day

30

minutes

6 to 8 hours

nitroglycerin patch

(Minitran, Nitro-Dur, Transderm-Nitro)

Placed on the upper body or upper arm

8 to 14 hours

* If chest pain persists after three doses, call 911. You may be having a heart attack.