Common uses

Isosorbide mononitrate is in a class of drugs called nitrates. Isosorbide mononitrate dilates (widens or relaxes) blood vessels (arteries and veins). When blood vessels are dilated, it is easier for the heart to pump. Also, more blood, which is rich in oxygen, can flow to the heart.
Isosorbide is used to prevent angina attacks (chest pain).
Isosorbide mononitrate may also be used for purposes other than those listed in this medication guide.

Before using

Before taking this medication, tell your doctor if you
• have had a heart attack
• have congestive heart failure
• have low blood pressure;
• have had a stroke, a transient ischemic attack (TIA, or mini-stroke), or a serious head injury;
• have anemia;
• have an allergy to nitrates;
• have closed-angle glaucoma;
• suffer from migraines;
• have kidney disease; or
• have liver disease.
The conditions listed above may prevent you from taking isosorbide or you may need a dosage adjustment or special monitoring during your therapy.
Isosorbide mononitrate is in the FDA pregnancy category C. This means that it is not known whether it will harm an unborn baby. Do not take isosorbide mononitrate without first talking to your doctor if you are pregnant. It is also not known whether isosorbide passes into breast milk. Do not take isosorbide mononitrate without first talking to your doctor if you are breast-feeding a baby.
Directions

Take isosorbide mononitrate exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water.
Isosorbide is usually taken first thing in the morning before breakfast. Follow your doctor's instructions.
Swallow the extended-release forms of isosorbide mononitrate whole. Do not crush or chew them. They are specially formulated to release medication slowly into your body. Do not stop taking isosorbide mononitrate suddenly. Stopping suddenly could cause a severe angina attack. Store the tablets at room temperature away from moisture and heat. Isosorbide mononitrate tablets must be stored in the container that your pharmacist gives them to you in. Throw away any leftover isosorbide mononitrate on the expiration date. Expired isosorbide will not treat your condition.

Cautions

Use isosorbide mononitrate exactly as directed. Follow your doctor's instructions, especially about the timing of your doses. Your blood needs to be free of isosorbide mononitrate for a certain period every day.
You may develop a headache because of this medicine, but do not stop taking it. Take aspirin or acetaminophen to treat the headache. Ask your doctor which is best for you. This side effect usually goes away as treatment with isosorbide mononitrate continues.
Do not stop taking isosorbide mononitrate suddenly. Stopping suddenly could cause a severe angina (chest pain) attack.
Do not drink alcohol while taking this medication.

Possible side effects

Side effects that you should report to your prescriber or health care professional as soon as possible:
•bluish discoloration of lips, fingernails, or palms of hands
•dizziness or fainting
•dry mouth
•irregular heartbeat, palpitations
•low blood pressure
•skin rash
•sweating
•the feeling of extreme pressure in the head
•unusual tiredness or weakness

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
•flushing of the face or neck
•headache
•nausea, vomiting

If you take too much

Seek emergency medical attention.
Symptoms of an isosorbide mononitrate overdose include a severe throbbing headache, difficult or slow breathing, muscle cramps, nausea, vomiting, diarrhea, fever, dizziness, fainting, an irregular heartbeat, changes in vision, flushing, and seizures.

Additional information

Use caution when driving, operating machinery, or performing other hazardous activities. Also, stand up slowly from a sitting or lying position. Isosorbide mononitrate may cause dizziness. If you experience dizziness, avoid hazardous activities. Avoid alcohol. It also widens your blood vessels and it can cause very low blood pressure, dizziness and drowsiness and you could endanger yourself or others.
Do not stop taking isosorbide mononitrate suddenly.

Drug interactions

Since isosorbide mononitrate can cause hypotension (low blood pressure), other medications which can reduce blood pressure may produce additive effects causing serious drops in blood pressure. Such drugs might include those used to treat high blood pressure, some antidepressants; some anti-psychotics, quinidine, procainamide, benzodiazepines such as diazepam (Valium) or opiates (e.g. morphine).
Since ethanol also may intensify the blood pressure lowering effect of isosorbide mononitrate, patients receiving isosorbide mononitrate should be advised to use ethanol with caution.