Patient Medication Information: uses, side effects, how to take - Isdn
What is ISDN used for?
ISDN is used in adults to prevent chest pain (angina) caused by too little blood and oxygen getting to the heart muscle.
How does ISDN work?
ISDN belongs to a group of medicines called nitrates. It relaxes and widens your blood vessels, which lets more blood and oxygen reach the heart muscle.
What are the ingredients in ISDN?
Medicinal ingredients: Isosorbide dinitrate
Non-medicinal ingredients: Colloidal silicon dioxide (5 mg and 30 mg tablets only), croscarmellose sodium, D&C Red #30 AL Lake (5 mg tablets only), lactose monohydrate, magnesium stearate and microcrystalline cellulose.
ISDN comes in the following dosage forms:
Sublingual tablets: 5 mg.
Oral tablets: 10 mg and 30 mg.
Do not use ISDN if:
- you are allergic to isosorbide dinitrate, to any other nitrate medicines or to any of the other ingredients in this medicine.
- you are taking medicines known as phosphodiesterase type 5 inhibitors. This includes erectile dysfunction medications such as VIAGRA® (sildenafil), CIALIS® (tadalafil) and vardenafil. Taking one of these medicines with ISDN may cause a dangerous fall in blood pressure and result in collapse, unconsciousness and could be fatal.
- you are taking riociguat (a medicine used to treat high blood pressure in the lungs). If you are unsure, ask your healthcare professional.
- you have cardiogenic shock (your heart is not delivering enough oxygen around your body).
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take ISDN. Talk about any health conditions or problems you may have, including if you:
- have recently had a heart attack or stroke.
- have congestive heart failure.
- have low blood pressure.
- have been taking any nitrate or nitrite medicines similar to ISDN.
- have an eye disease called glaucoma.
- have kidney problems.
- have lactose intolerance.
are pregnant, think you are pregnant, or planning to be pregnant.
- are breastfeeding.
Other warnings you should know about:
Tolerance: If you take ISDN continuously throughout the day for a certain period of time, you may build up a tolerance to it, or other nitrates and nitrites. To try and prevent tolerance, your healthcare professional may advise you not to take any ISDN for a certain number of hours (“ISDN-free period”) each day.
Driving and using machines: ISDN may cause dizziness, fatigue, or blurred vision. Give yourself time after using ISDN to see how you feel before driving a vehicle or using machinery.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
Serious Drug Interactions:
Do NOT take ISDN with:
- medicines known as phosphodiesterase type 5 inhibitors. This includes erectile dysfunction medications such as VIAGRA® (sildenafil), CIALIS® (tadalafil) and vardenafil.
- riociguat, a medicine used to treat high blood pressure in the lungs.
The following may also interact with ISDN:
- Epinephrine, used in emergencies to treat very serious allergic reactions.
- Acetylcholine, used for eye surgeries, activate skeletal muscles.
- Medications used to lower blood pressure.
Alcohol.
How to take ISDN:
- Follow the directions given to you by your healthcare professional.
Sublingual Tablets
- ISDN sublingual tablet is absorbed through the lining of your mouth.
- Place your ISDN tablet under your tongue, or in your cheek and allow to dissolve.
- Tablets will dissolve in 20 seconds in the mouth.
- Do NOT chew, crush or swallow your ISDN tablet whole, as swallowed sublingual tablets are NOT effective.
- While the tablet is dissolving, avoid eating, drinking or smoking until the tablet has completely dissolved.
Oral Tablets
- Swallow ISDN oral tablets whole with a glass of water.
- Do not chew or crush the tablets.
Usual dose:
Sublingual Tablets: 5 to 10 mg sublingually (1 to 2 sublingual 5 mg tablets), every 2 to 4 hours for the prevention of short-term chest pain; may be supplemented by a dose of 5 to 10 mg sublingually prior to stressful situations likely to provoke an attack of angina.
Oral Tablets: 20 to 120 mg daily, in divided doses as recommended by your healthcare professional.
Overdose:
If you think you, or a person you are caring for, have taken too much ISDN, contact a healthcare professional, hospital emergency department, regional poison control centre or Health Canada’s toll-free number, 1-844 POISON-X (1-844-764-7669) immediately, even if there are no signs or symptoms.
Missed Dose:
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the next dose at the regular scheduled time. Do NOT double your dose to make up the missed dose.
What are possible side effects from using ISDN?
These are not all the possible side effects you may have when taking ISDN. If you experience any side effects not listed here, tell your healthcare professional.
Side effects may include:
- headache
- light-headedness
- dizziness
- weakness
- flushing of the face
- nausea or vomiting
- restlessness
- sweating
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
| Only if severe | In all cases | ||
| UNCOMMON | |||
| Rebound hypertension (sudden increase in blood pressure when a person stops taking certain medications): headache, fast heart rate of over 100 beats per minute (bpm), nausea, flushed skin, warm feeling, tightness in the chest, tremors, anxiety, nervousness, difficulty seeing | √ | ||
| Syncope (fainting and passing out) | √ | ||
| Unstable angina (worsening chest pain) that occurs with less exertion, and lasts longer than stable angina | √ | ||
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
| Only if severe | In all cases | ||
| RARE | |||
Cerebral ischemia (not enough blood flow to the brain): sudden weakness, difficulty speaking, blurred vision, dizziness, confusions, loss of conciousness | √ | ||
| Collapse | √ | ||
| Exfoliative dermatitis (severe skin reaction): red, scaly and peeling skin | √ | ||
| Hypotension (low blood pressure): dizziness, fainting, light-headedness, blurred vision, nausea, vomiting, fatigue (may occur when you go from lying or sitting to standing up) | √ | ||
| VERY RARE | |||
| Methemoglobinemia (a type of blood disorder): headache, nausea, dizziness, fatigue, shortness of breath, blue coloured skin, fast heart rate, chocolate-coloured blood | √ | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting Side Effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
- Visiting the Web page on Adverse Reaction Reporting (canada.ca/drug-device-reporting) for information on how to report online, by mail or by fax; or
- Calling toll-free at 1-866-234-2345.
NOTE: Contact your healthcare professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.
Storage:
Store at room temperature 15°C to 30°C.
Protect from moisture.
Keep out of reach and sight of children.
If you want more information about ISDN:
- Talk to your healthcare professional
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html); the manufacturer’s website (https://www.aapharma.ca/en/), or by calling 1-877-998-9097.
Date of Authorization: 2025-05-30
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