ISM

Indications

Isosorbide Mononitrate is used to prevent chest pain (angina) caused by coronary heart disease. It is taken regularly to reduce the number of angina attacks. It does not work fast enough to stop an attack that has already started.

How It Works

It is a nitrate. It relaxes and widens blood vessels, so the heart has less work to do and needs less oxygen. This helps prevent angina.

Dosage and Administration

• Standard tablets: usually 20 mg two times a day, or as the doctor advises. The second dose is usually taken about 7 hours after the first (for example 8 am and 3 pm) so that there is a nitrate-free gap overnight.
• Modified-release (once-daily) tablets or capsules: usually 30 to 60 mg once in the morning, increased by the doctor if needed.

Swallow modified-release forms whole with water; do not crush or chew them. The doctor may start with a lower dose to reduce headache.

Interactions

Never take it with Sildenafil, Tadalafil, Vardenafil or Riociguat, as blood pressure can fall to a dangerous level. Other blood pressure medicines, alcohol, and some antidepressants can add to the drop in blood pressure. Tell your doctor about all the medicines you take.

Contraindications

• Allergy to nitrates or any ingredient of the product.
• Very low blood pressure, shock, or severe anaemia.
• Some heart valve and heart muscle problems (such as severe aortic stenosis or hypertrophic obstructive cardiomyopathy).
• Use of Sildenafil or similar medicines.

Side Effects

Headache is common in the first days and usually eases with time. Others include dizziness, flushing, fast heartbeat, nausea and feeling faint when standing up quickly.

Get urgent medical help if you have chest pain that does not settle with rest or your rescue spray or tablet, fainting, severe dizziness, or signs of an allergic reaction such as swelling of the face or difficulty breathing.

Pregnancy and Lactation

There is limited information. Use only if the doctor decides the benefit is greater than the risk. Ask your doctor before using it while breastfeeding.

Precautions and Warnings

Do not stop taking it suddenly, as angina may get worse. Stand up slowly to avoid dizziness. Avoid alcohol. Take care with driving until you know how it affects you. Use with caution in people with low blood pressure, recent heart attack, glaucoma or thyroid problems.

Overdose

Too much can cause severe headache, very low blood pressure, fainting, fast heartbeat and bluish lips. Seek emergency medical help.

Therapeutic Class

Nitrate (anti-anginal medicine).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.