Isosorbide Mononitrate (Oral)


Isosorbide mononitrate is a drug used in the prevention of angina which is caused by coronary artery disease. It doesn't work quick enough to relieve the pain of an angina attack that has already begun.

This drug belongs to the group of medications known as nitrates. They work by relaxing the blood vessels and increasing the supply of oxygen and blood to the heart whilst reducing its overall workload. If it is used on a regular basis for a long period of time, it can help prevent angina attacks. You cannot obtain this drug on your own. It is only available via a prescription from your doctor. It is available in the dosage forms of extended-release tablet and tablet.

Conditions treated

  • Prevent bleeding varicose vein in the esophagus

Type of medication

  • Nitrate

Side effects

Alongside treating angina attacks, this medication can cause some unwanted side effects. However, not all of these side effects may occur but if they do, you may need to seek medical attention.

You should contact your doctor right away if you suffer from any of the following side effects whilst taking Isosorbide Mononitrate:

Less common


  • Dark urine

Seek emergency help immediately right away if you suffer from any of the following symptoms of overdose:

Symptoms of overdose

  • Change in consciousness

Some of the side effects that occur don't typically require medical attention. You usually find that these side effects begin to reduce once your body starts adjusting to the medication. If, however, they are giving you bother, you can seek advice from your doctor or healthcare professional for advice on ways to reduce or prevent the intensity of these side effects. Check with your doctor if any of the following side effects are persistent or become bothersome.

Less common

Listening with a stethoscope

  • Increased appetite

You may suffer from other side effects that are not listed above. You should contact your doctor or healthcare professional if you notice anything unusual. You can report side effects to the FDA on 1-800-FDA-1088 regardless of severity.


The final dose of any medication will depend on different factors. Your doctor will take into account your age, weight, and height, other medical conditions you may suffer from, alongside any treatment you take for that medical condition. Your doctor will also consider how long you are taking treatment for, the strength of the medication and your reaction to the first dose. Do not change your dose without advice from your doctor, as to do so could increase your risk of overdose or severe interactions. If you take too little of this medication you could reduce its effectiveness in treatment. Do not share this medication with anyone else.

Extended-release tablets - For the prevention of angina with oral dosage form:

Adults: An initial dose of thirty or sixty milligrams once a day. Take the dose in the morning as soon as you want up. Your doctor can increase your dose as necessary.

Children: The dose and use will be determined by your doctor.

For oral dosage form (tablets):

Adults: twenty milligrams twice a day. Take the first dose in the morning as soon as you wake up and the second dose seven hours later.

Children: The dose and use will be determined by your doctor.

Missed Dose

If you miss a dose of this medication you should take it as soon as you remember, unless it is time for your next dose. In this instance, you should skip the missed dose and return to your original dosing scheduled. Don't double your doses.

Proper Use

This variation of nitrate is used in reducing the amount of angina attacks that occur over a long period of time. It cannot relieve the pain of an attack that has already begun as it's a slow-release medication. The extended-release form gradually releases mediation to provide its effect for eight to ten hours. You should consult with your doctor about whether you require a fast-acting medication to receive the pain associated with an angina attack.

You should take this medication in the morning when you wake up and follow the same schedule every day. This medication will work best if you have a "drug-free" period of time daily when you don't take it. Your healthcare professional will schedule a "drug-free" period into your day alongside your other doses. You should follow this schedule carefully so the medication can work properly.

Ensure that you swallow the extended-release tablet whole alongside a half glass of water. Don't crush, chew or split it.


This drug can interact with a number of other medications. These interactions can produce severe side effects and/or reduce the effectiveness of either drug in its treatment. To help prevent these interactions from occurring, it's important to give your healthcare team a complete list of all the medications you are currently taking and other medical conditions you may suffer from. This list should include all herbal products, vitamin supplements, and prescription/nonprescription drugs. In most cases, your doctor will avoid interactions by avoiding the use of this drug, but in some cases, it may be still be required.

This use of this medication alongside any of the following medicines is not typically recommended. Your doctor may avoid treating you with this drug altogether to change some of the other medications you are currently taking.

  • Avanafil

Over 280 drugs can interact with this medication. You should let your doctor know if you are taking any of the following drugs as interactions could occur.

  • Methysergide maleate

This list is not complete.

Other medical conditions

If you suffer from other medical conditions, this too could affect your use of this medication. Let your doctor know if you have other medical conditions, especially:

  • Hypotension (low blood pressure). This drug should not be used in those who suffer from this condition.



You should let your doctor know if you have ever suffered from an allergic reaction to this medication or similar medications. You should also make your health team aware of any other allergic reactions you may suffer from including to animals, food, dyes or preservatives.

Pediatric population

No appropriate studies have been conducted on the relationship of age to the effects of isosorbide mononitrate in the pediatric population. Therefore, efficacy and safety have not yet been established.

Geriatric population

Appropriate studies conducted to date have not indicated a geriatric-specific problem that could limit the effectiveness of isosorbide mononitrate in the older population. However, older patients are more likely to suffer from severely low blood pressure and age-related kidney, liver or heart conditions. Therefore, a degree of caution should be exercised and an adjustment in the dose for those who are receiving this drug.

Use in pregnancy and breastfeeding

This drug is under FDA pregnancy category B. It's unknown whether Isosorbide Mononitrate could harm an unborn child. Let your doctor know if you are pregnant or intend to become pregnant.

It's unknown whether this drug can pass into breast milk or if it could harm a nursing infant. Let your doctor or healthcare professional know if you are currently breastfeeding.

If you are taking this medication for a long period of time, it's important that your doctor monitors your progress at regular appointments to ensure that this medication is working correctly. Your doctor may take urine or blood tests to test for unwanted side effects.

Do not take sildenafil (Viagra®), riociguat (Adempas®), tadalafil (Cialis®), or vardenafil (Levitra®) whilst you are using this medication. The use of these medications in combination can lower your blood pressure and cause dizziness, blurred vision, fainting or lightheadedness. If you're taking this medication and you experience an angina attack, you must go to the hospital immediately.

This medication can cause headaches. This is normal as these are a sign that the drug is working. Don't stop using the medication or change the schedule in order to avoid the headaches. You should speak with your doctor if you are offering from severe pain.

Faintness, lightheadedness or dizziness may occur, especially when you get up quickly from a sitting or lying position. You should arise slowly to help alieve these symptoms.

Fainting, lightheadedness or dizziness is also more likely to occur if you stand for long periods of times, engage in exercise or drink alcohol, or the weather is hot. You should limit your intake of alcohol whilst using this drug. Also, care should be taken when exercising or in hot weather and if you are standing for a long period of time.

Don't stop using this medication without consulting with your doctor beforehand. They may want to reduce the amount of medication you are taking before you stop it completely.

Ensure that any dentist or doctor who treats you knows about this drug. You may need to stop using this medication several days before you take medical tests as it could interfere with the results.


Isosorbide Mononitrate should be stored in a closed container and keep at room temperature. It needs to be safe from direct light, heat, and moisture also. Do not let this medication freeze. Keep out of the reach of children. Don't keep medication you no longer need or that has passed its expiry date. You should seek advice from a local pharmacist for the best method of disposal for a medication you no longer need.


When used correctly, Isosorbide Mononitrate is successful in the prevention of angina attacks. However, due to the number of interactions possible, it's important that your healthcare team know about any other medical conditions and corresponding medications you are taking.

This drug cannot treat an angina attack that is already occurring as it does not work quick enough. You may be required to take a fast-acting medication alongside this drug to treat the pain and discomfort associated with angina attacks.

It's important to take this medication as has been directed by your medical team. This is because if you take too much medication you could increase your risk of an overdose and if you take too little you could reduce your treatment.

The safety and efficacy of this drug have not been established in children. You should let your doctor know if you are currently pregnant or intend on becoming pregnant whilst using this drug. You should also inform your healthcare team if you are currently breastfeeding.

Take caution when exercising, standing for long periods of time, in hot weather when using this medication and reduce your intake of alcohol. This medication can make you feel dizzy, faint and lightheaded. If you require any further information about the practical uses of Isosorbide Mononitrate or you have any other questions or queries, you should contact your local healthcare professional or doctor for further advice.