Common uses

Isosorbide mononitrate is used to prevent chest pain (angina). When used regularly, isosorbide can decrease the number and severity of attacks of chest pain from angina and improve your ability to exercise. This medication is called a nitrate. It works by relaxing blood vessels and allowing more blood to flow to the heart.
This medication should not be used to treat angina when it occurs. Use other medications (e.g., sublingual nitroglycerin) to relieve an angina attack as directed by your doctor. Consult your doctor or pharmacist for details.

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.
Imdur is in the FDA pregnancy category C. This means that it is not known whether it will harm an unborn baby. Do not take Imdur without first talking to your doctor if you are pregnant. It is also not known whether isosorbide passes into breast milk. Do not take Imdur without first talking to your doctor if you are breast-feeding a baby.


Directions

Take Imdur 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 Imdur tablets whole. Do not crush or chew them. They are specially formulated to release medication slowly into your body. Do not stop taking Imdur suddenly. Stopping suddenly could cause a severe angina attack. Store the tablets at room temperature away from moisture and heat. Imdur tablets must be stored in the container that your pharmacist gives them to you in. Throw away any leftover Imdur on the expiration date. Expired isosorbide will not treat your condition.

Cautions

Use Imdur 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 Imdur continues.
Do not stop taking Imdur suddenly. Stopping suddenly could cause a severe angina (chest pain) attack.
Do not drink alcohol while taking this medication.

Possible side effects

If you experience any of the following serious side effects, stop taking Imdur and seek emergency medical attention:
• an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
• blurred vision or dry mouth; or
• irregular heartbeat;
• fainting.
Other, less serious side effects may be more likely to occur. Continue to take isosorbide and talk to your doctor if you experience
• headache or dizziness,
• flushing (redness of the face, neck, and chest),
• nausea or vomiting,
• a fast heartbeat,
• swollen ankles, or
• weakness.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

If you take too much

Any medication taken in excess can have serious consequences. Severe overdosage of Imdur can be fatal. If you suspect an overdose, seek medical help immediately.
• Symptoms of Imdur overdose may include:
Air hunger, bloody diarrhea, coma, confusion, difficulty breathing, fainting, fever, nausea, palpitations, paralysis, pressure in the head, profuse sweating, seizures, skin either cold and clammy or flushed, slow heartbeat, throbbing headache, vertigo, visual disturbances, vomiting

Additional information

Use caution when driving, operating machinery, or performing other hazardous activities. Also, stand up slowly from a sitting or lying position. Imdur 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 Imdur suddenly.

Drug interactions

Do not use sildenafil (Viagra), a drug used to treat impotence, while taking Imdur. The combination could cause severe or life-threatening low blood pressure.
Before taking Imdur, tell your doctor if you are taking any of the following medicines:
• dihydroergotamine (D.H.E. 45); or
• any other heart medicines, especially those used to treat high blood pressure or irregular heartbeats.
You may require a dosage adjustment or special monitoring during your treatment if you are taking any of the medicines listed above.
Do not drink alcohol. Like Imdur, alcohol widens your blood vessels, and it can cause very low blood pressure, dizziness, and drowsiness. If you combine Imdur and alcohol, you could endanger yourself or others.
Drugs other than those listed here may also interact with Imdur or affect your condition. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.