Isosorbide dinitrate is used to prevent chest pain (angina) in patients with a certain heart condition (coronary artery disease). This medication belongs to a class of drugs known as nitrates. It works by relaxing and widening blood vessels so blood can flow more easily to the heart.

This medication will not relieve chest pain once it occurs. It is also not intended to be taken just before physical activities (such as exercise, sexual activity) to prevent chest pain. Other medications may be needed in these situations. Consult your doctor for more details.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This medication may also be used with other drugs to improve the symptoms of heart failure (such as trouble breathing).

Take this medication by mouth as directed by your doctor, usually 2 to 3 times daily. It is important to take the drug at the same times each day. Do not change the dosing times unless directed by your doctor.

Use this medication regularly to get the most benefit from it. Do not suddenly stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.

Although unlikely, when this medication is used for a long time, it may not work as well and may require different dosing. Tell your doctor if this medication stops working well (for example, you have worsening chest pain or it occurs more often).

Headache, dizziness, lightheadedness, nausea, and flushing may occur as your body adjusts to this medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Headache is often a sign that this medication is working. Your doctor may recommend treating headaches with an over-the-counter pain reliever (such as acetaminophen, aspirin). If the headaches continue or become severe, tell your doctor promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• fainting
• fast/irregular/pounding heartbeat

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or to similar drugs (such as isosorbide mononitrate, nitroglycerin); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• recent head injury
• anemia
• low blood pressure
• dehydration
• other heart problems (such as recent heart attack)

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this medication, especially dizziness and lightheadedness, which could increase the risk of falls.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, tadalafil)
• certain drugs to treat migraine headaches (ergot alkaloids such as ergotamine)
• riociguat
• vericiguat

Some products have ingredients that could worsen your heart failure. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen).

Isosorbide dinitrate is very similar to isosorbide mononitrate. Do not use medications containing isosorbide mononitrate while using isosorbide dinitrate.

This medication may interfere with certain lab tests (such as blood cholesterol levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: slow heartbeat, vision changes, severe nausea/vomiting, sweating, cold/clammy skin, bluish fingers/toes/lips.

Do not share this medication with others.

Lab and/or medical tests (such as blood pressure monitoring) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Lifestyle changes such as dietary changes, exercise, and stopping smoking may help this drug work better. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.

If you miss a dose, take it as soon as you remember. If it is within 2 hours of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).