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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:

You should not use this medicine if you have had an allergic reaction to isosorbide or similar medicines (such as nitroglycerin or Isordil®). You should not use this medicine if you are also using Viagra®.

How to Use This Medicine:

Tablet, Long Acting Tablet

  • Your doctor will tell you how much of this medicine to take and how often. Do not take more medicine or take it more often than your doctor tells you to.
  • Take this medicine exactly as directed, or it will not work properly. Most people use this medicine for only part of each day.
  • It is best to take this medicine on an empty stomach with at least half a glass of water.
  • Swallow the extended-release tablet whole. Do not break, crush, or chew it.
  • Never share your medicine with anyone.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If your next regular dose is less than 2 hours away, wait until then to use the medicine and skip the missed dose.
  • Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine at room temperature in a closed container, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

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

  • Make sure your doctor knows if you are also using diuretics or "water pills" (such as furosemide, hydrochlorothiazide, Hyzaar®), or heart or blood pressure medicine (such as verapamil, Adalat®, Calan®, Cardizem®, Lotrel®, Plendil®, Procardia®, Tiazac®).
  • Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have low blood pressure, congestive heart failure (CHF), an enlarged heart, or other heart problems.
  • 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. You may take aspirin or Tylenol® to relieve the headache. If you have severe pain, talk with your doctor.
  • This medicine may make you dizzy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert. You may feel lightheaded when standing, so stand up slowly.
  • Do not stop using this medicine suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely.

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 face or hands, swelling or tingling in the mouth or throat, tightness in chest, trouble breathing
  • Blue lips or fingernails, trouble breathing
  • Severe or ongoing dizziness, lightheadedness, or fainting
  • Slow heartbeat, increased chest pain
  • Throbbing, severe, or ongoing headache, confusion, low fever, or trouble seeing

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

  • Nausea, vomiting
  • Sweating, facial flushing

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: 4/4/2014

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