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Isosorbide mononitrate (By mouth)

Isosorbide Mononitrate (eye-soe-SOR-bide mon-oh-NYE-trate)

Prevents angina (chest pain). This medicine is a nitrate.

Brand Name(s):

Imdur, Imdur ER, Ismo

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use if you had an allergic reaction to isosorbide or similar medicines.

How to Use This Medicine:

Tablet, Long Acting Tablet

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you. You should take this medicine first thing in the morning. Carefully follow the same schedule each day so the medicine will work properly.
  • It is best to take this medicine on an empty stomach with at least half a glass of water.
  • Do not break the 30-milligram tablet.
  • Swallow the extended-release tablet whole. Do not crush, break, or chew it.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Do not use this medicine together with sildenafil, tadalafil, or vardenafil.
  • Some foods and medicines can affect how isosorbide mononitrate works. Tell your doctor if you are using a diuretic (water pills, such as furosemide, hydrochlorothiazide) or blood pressure medicine or if you drink alcohol.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have a recent heart attack, congestive heart failure (CHF), an enlarged heart, low blood pressure, or other heart problems.
  • This medicine may cause the following problems:
    • Severe low blood pressure
    • Worsening of chest pain caused by an enlarged heart
  • Medicines that treat chest pain sometimes cause headaches. These headaches are a sign that the medicine is working. Do not stop taking the medicine or change the time you take it in order to avoid the headaches. Ask you doctor if you can take aspirin or acetaminophen to treat the headache.
  • This medicine may make you dizzy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. You may feel lightheaded when standing, so stand up slowly.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Severe or ongoing dizziness, lightheadedness, or fainting
  • Severe headache
  • Slow heartbeat, increased chest pain

If you notice these less serious side effects, talk with your doctor:

  • Mild headache

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 9/4/2014


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