Nitrates (NYE-trates) are used to treat the symptoms of Angina (chest pain). Depending on the type of dosage form and how it is taken, nitrates are used to treat angina in three ways:
- to relieve an attack that is occurring by using the medicine when the attack begins;
- to prevent attacks from occurring by using the medicine just before an attack is expected to occur; or
- to reduce the number of attacks that occur by using the medicine regularly on a long-term basis.
When taken orally and swallowed, nitrates are used to reduce the number of angina attacks that occur. They do not act fast enough to relieve the pain of an angina attack.
Nitrates work by relaxing blood vessels and increasing the supply of blood and oxygen to the heart while reducing its work load.
Nitrates may also be used for other conditions as determined by your doctor.
The nitrates discussed here are available only with your doctor’s prescription, in the following dosage forms:
- Oral Isosorbide dinitrate o Extended-release capsules (U.S.) o Tablets (U.S. and Canada) o Chewable tablets (U.S.) o Extended-release tablets (U.S. and Canada)
- Isosorbide mononitrate o Extended-release tablets (U.S.) o Tablets (U.S.)
- Nitroglycerin o Extended-release capsules (U.S.) o Extended-release tablets (U.S. and Canada)
Before Using This Medicine
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 nitrates, 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. However, studies in rabbits given large doses of isosorbide dinitrate have shown adverse effects on the fetus. 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 these medicines pass 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 taking nitrates, 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 nitrates 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.
Other medical problems- The presence of other medical problems may affect the use of nitrates. Make sure you tell your doctor if you have any other medical problems, especially:
- Anemia (severe)
- Glaucoma - May be worsened by nitrates
- Head injury (recent) or
- Stroke (recent)- Nitrates may increase pressure in the brain, which can make problems worse
- Heart Attack (recent)- Nitrates 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
Proper Use of This Medicine
Take this medicine exactly as directed by your doctor. It will work only if taken correctly.
This form of nitrate is used to reduce the number of angina attacks. In most cases, it will not relieve an attack that has already started because it works too slowly (the extended-release form releases medicine gradually over a 6-hour period to provide its effect for 8 to 10 hours). Check with your doctor if you need a fast-acting medicine to relieve the pain of an angina attack.
Take this medicine with a full glass (8 ounces) of water on an empty stomach. If taken either 1 hour before or 2 hours after meals, it will start working sooner.
Extended-release capsules and tablets are not to be broken, crushed, or chewed before they are swallowed. If broken up, they will not release the medicine properly.
The dose of nitrates 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.
The number of capsules or tablets that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking nitrates.
- For isosorbide dinitrate For angina (chest pain): o For regular (short-acting) oral dosage forms (capsules or tablets): + Adults-5 to 40 mg four times a day. + Children-Dose must be determined by your doctor. o For long-acting oral dosage forms (extended-release capsules or tablets): + Adults-20 to 80 mg every eight to twelve hours. + Children-Dose must be determined by your doctor.
- For isosorbide mononitrate For angina (chest pain): o For regular (short-acting) oral dosage form (tablets): + Adults-20 mg two times a day. The two doses should be taken seven hours apart. + Children-Use and dose must be determined by your doctor. o For long-acting oral dosage forms (extended-release tablets): + Adults-30 to 240 mg once a day. + Children-Use and dose must be determined by your doctor.
- For nitroglycerin For angina (chest pain): o For long-acting oral dosage forms (capsules or tablets): + Adults-2.5 to 9.0 mg every eight to twelve hours. + Children-Dose must be determined by your doctor.
If you are taking this medicine regularly and you miss a dose, take it as soon as possible. However, if the next scheduled dose is within 2 hours (or within 6 hours for extended-release capsules or tablets), skip the missed dose and go back to your regular dosing schedule. Do not double doses.
To store this medicine:
- 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.
Precautions While Using This Medicine
Do not take sildenafil (e.g., Viagra), tadalafil (e.g., Cialis), or vardenafil (e.g., Levitra) if you are taking this medicine. When sildenafil, tadalafil, or vardenafil are taken with nitrates, the combination can lower blood pressure and cause dizziness, lightheadedness, or fainting. In some cases, sildenafil, tadalafil, or vardenafil taken with nitrates has caused death . If you are taking sildenafil, tadalafil, or vardenafil and you experience an angina attack, you must go to the hospital right away.
If you have been taking this medicine regularly for several weeks or more, do not suddenly stop using it. Stopping suddenly may bring on attacks of angina. Check with your doctor for the best way to reduce gradually the amount you are taking before stopping completely.
Dizziness, lightheadedness, or faintness may occur , especially when you get up quickly from a lying or sitting position. Getting up slowly may help. If you feel dizzy, sit or lie down.
The dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking this medicine, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for long periods of time.
After taking a dose of this medicine you may get a headache that lasts for a short time. This is a common side effect, which should become less noticeable after you have taken the medicine for a while. If this effect continues, or if the headaches are severe, check with your doctor.
For patients taking the extended-release dosage forms of isosorbide dinitrate:
- Partially dissolved tablets have been found in the stools of a few patients taking the extended-release tablets. Be alert to this possibility, especially if you have frequent bowel movements, diarrhea, or digestive problems. Notify your doctor if any such tablets are discovered. The tablets must be properly digested to provide the correct dose of medicine.
Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- Rare o Blurred vision; dryness of mouth; headache (severe or prolonged); skin rash
- Signs and symptoms of overdose (in the order in which they may occur) o Bluish-colored lips, fingernails, or palms of hands; dizziness (extreme) or fainting; feeling of extreme pressure in head; shortness of breath ; unusual tiredness or weakness; weak and fast heartbeat; fever; convulsions (seizures) Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:
- More common o Dizziness or lightheadedness, especially when getting up from a lying or sitting position; fast pulse; flushing of face and neck; headache ; nausea or vomiting; restlessness
Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.
Some commonly used brand names are:
In the U.S.-
- Isordil Tembids
- Isordil Titradose
- Nitroglyn E-R
Revision date: July 3, 2011
Last revised: by Andrew G. Epstein, M.D.
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