Isosorbide Mononitrate

What Is Isosorbide and How Does It Work?

Isosorbide mononitrate is a prescription drug indicated for the prevention of angina pectoris due to coronary artery disease.

  • The onset of action of oral isosorbide mononitrate is not sufficiently rapid for this product to be useful in aborting an acute anginal episode.
  • Isosorbide mononitrate is available under the following different brand names: Imdur, Monoket, and ISMO.

What Are Dosages of Isosorbide Mononitrate?

Dosages of Isosorbide Mononitrate:

Adult and Pediatric Dosages:


  • 10 mg
  • 20 mg

Tablets, extended-release

  • 30 mg
  • 60 mg
  • 120 mg

Dosage Considerations – Should be Given as Follows:

Angina Pectoris

Adult Dosage:

  • Prevention of angina pectoris caused by coronary artery disease
  • Immediate release: 5-10 mg orally twice daily initially (5 mg in small patients) given each dose 7 hours apart; increased to 10 mg orally every 12 hours by day 2 or 3; maintenance: 20 mg orally every 12 hours
  • Extended-release: 30-60 mg orally once daily in the morning initially; may be increased to 120 mg orally once daily; wait at least 3 days between increases; if warranted may increase up to 240 mg orally once daily (rare)
  • Geriatric:
    • Start with the lowest recommended adult dosage

Dosing considerations

  • Take on an empty stomach, 30 minutes before meals or 1 hour after a meal
  • Take on an empty stomach, 30 minutes before or 1 hour after a meal
  • Extended-release tablet should be swallowed whole; must not be chewed, crushed, or split


  • Safety and efficacy not established

What Are Side Effects Associated with Using Isosorbide?

Common side effects of isosorbide include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Isosorbide?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Isosorbide?


This medication contains isosorbide mononitrate. Do not take Imdur, Monoket, or ISMO if you are allergic to isosorbide mononitrate or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity to organic nitrates
  • PDE-5 inhibitors (avanafil, sildenafil, tadalafil, or vardenafil); concomitant use can cause severe hypotension, syncope, or myocardial ischemia
  • Concomitant administration with guanylate stimulator riociguat (may cause hypotension)

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Isosorbide?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Isosorbide?"


Pregnancy and Lactation

  • Use isosorbide mononitrate during pregnancy with caution if benefits outweigh risks. Animal studies show risk and human studies are not available, or neither animal nor human studies were done.
  • Use isosorbide mononitrate with caution when breastfeeding, as it is unknown if isosorbide mononitrate crosses into breast milk.
Medscape. Isosorbide Mononitrate.
RxList. Imdur Monograph.

Health Solutions From Our Sponsors