Headache, dizziness, lightheadedness, nausea, and flushing may occur as your body adjusts to the 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). 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. This medication may rarely cause nerve problems. Tell your doctor promptly if you experience numbness or tingling. Your doctor may recommend a vitamin B6 supplement (pyridoxine). Tell your doctor right away if you have any serious side effects, including: severe tiredness, aching/swollen joints, rash on nose and cheeks, swollen glands, signs of kidney problems (such as change in the amount of urine, bloody/pink urine), signs of infection (such as sore throat that doesn't go away, fever, chills), easy bruising/bleeding, fainting, fast/irregular/pounding heartbeat. Get medical help right away if you have any very serious side effects, including: chest/jaw/left arm pain. 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.

Some products that may interact with this drug include: certain drugs to treat migraine headaches (ergot alkaloids such as ergotamine), drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, tadalafil), MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine), 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.