Isosorbide Mononitrate

What is Isosorbide Mononitrate?

  • Isosorbide Mononitrate is commonly prescribed to manage and prevent chest pain (angina) caused by coronary artery disease, and sometimes used in heart failure.

  • It falls under the class of drugs known as nitrates.

How Does it Work and Why is it Important to Take?

  • Isosorbide mononitrate works by relaxing and dilating blood vessels, facilitating the flow of oxygen-rich blood to the heart muscle.

  • This reduces the heart's workload, alleviating chest pain (angina) and safeguarding the heart from stress, lowering the risk of a heart attack for overall heart health.

The Dose of The Medication

  • The dose depends on your symptoms and the prescribed tablets or capsules.

  • For standard release, the starting dose is 10mg twice a day, and for modified release, it ranges from 25mg to 60mg once a day.

  • The maximum daily dose is 120mg.

How and When to Take It

  • Take Isosorbide mononitrate as prescribed by your clinician

  • You may be advised to have a “nitrate low period” to ensure it works properly. For instance, if taken twice a day, doses should be at 8 am and 2 pm, allowing a 6-hour gap.

What to Expect

  • Isosorbide mononitrate can work within an hour, but it may take a few days to prevent angina symptoms.

What to Do if You Miss a Dose

  • If you forget a dose, check the patient information leaflet for further information

Possible Side Effects

  • Weakness

  • Dizziness

  • Tired or drowsy

  • Headaches

  • Flushing

  • Swelling in the leg, ankles or feet

Management of Side Effects

  • Click here for common side effects and how to manage them.

  • Elevate your legs when resting if you experience swelling.

  • Some side effects improve as your body adjusts.

  • If severe, persistent or bothersome side effects occur, consult your GP, local pharmacy, or NHS 111.

Common Interactions

  • Inform your clinician about all medications, including over-the-counter and herbal supplements.

  • Consult your clinician before taking medications for erectile dysfunction.

  • Avoid over-the-counter ibuprofen or aspirin unless advised by a clinician.

Special Warnings

  • Limit alcohol intake, as it can increase medication side effects.

Monitoring Your Progress

  • Regular check-ups with your GP clinician are essential to monitor heart health and assess medication effectiveness.

Where to Find More Information and Who to Contact

  • Refer to the patient information leaflet and the NHS website for more details.

  • If you have questions or experience unusual symptoms, contact your GP clinician, local pharmacy, or NHS 111.