Imdur (isosorbide mononitrate) is in a group of drugs called nitrates. It dilates (widens) blood vessels, making it easier for blood to flow through them and easier for the heart to pump.
Take Imdur exactly as prescribed by your doctor.
Take this medication with at least 4 ounces of water or other liquid. Do not crush, chew, or break an extended-release tablet. Swallow the pill whole.
If possible, try to rest or stay seated when you use this medication. Imdur can cause dizziness or fainting. Use Imdur regularly to prevent an angina attack.
Do not stop taking Imdur suddenly. Stopping suddenly could cause a severe angina attack.
The usual adult dose of Imdur is 30-60 mg orally once a day. Follow your doctor's dosing instructions very carefully.
Store this medicine at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.
Do not use Imdur if you are taking sildenafil (Viagra, Revatio). A dangerous drug interaction could occur, leading to serious side effects. You should not use Imdur if you are allergic to isosorbide mononitrate, isosorbide dinitrate, (Isordil, Dilatrate, Isochron), or nitroglycerin, or if you have early signs of a heart attack (chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling).
To make sure you can safely take Imdur, tell your doctor if you have any of these other conditions:
congestive heart failure;
low blood pressure; or
Tell your doctor about all other medications you use, especially:
blood pressure medication;
dihydroergotamine (D.H.E. 45, Migranal) or ergotamine (Ergomar, Cafergot, and others);
an erectile dysfunction medication such as tadalafil (Cialis) or vardenafil (Levitra);
a beta blocker such as atenolol (Tenormin, Tenoretic), carvedilol (Coreg), labetalol (Normodyne, Trandate), metoprolol (Dutoprol, Lopressor, Toprol), nadolol (Corgard), propranolol (Inderal, InnoPran), sotalol (Betapace), and others;
heart or blood pressure medicine such as amlodipine (Norvasc, Caduet, Exforge, Lotrel, Tekamlo, Tribenzor, Twynsta, Amturnide), diltiazem (Cartia, Cardizem), nifedipine (Nifedical, Procardia), verapamil (Calan, Covera, Isoptin, Verelan), and others.
It is not known whether Imdur will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. It is not known whether isosorbide mononitrate passes into breast milk or if it could harm a nursing baby. Do not use Imdur without telling your doctor if you are breast-feeding a baby.
Call your doctor at once if you have a serious side effect such as:
fast, slow, pounding, or uneven heart rate;
feeling like you might pass out;
trouble breathing, blue-colored skin, tired feeling; or
worsening angina pain.
Less serious Imdur side effects may include:
headache, mild dizziness;
warmth, redness, or tingling under your skin;
nausea, vomiting, constipation, diarrhea;
pain or stiffness in joints or muscles;
hot flashes; or