Before taking isosorbide,
tell your doctor and pharmacist if you are allergic to isosorbide; nitroglycerin tablets, patches, or ointment; any other medications, or any of the ingredients in isosorbide tablets, extended-release tablets, or extended-release capsules. Ask your pharmacist for a list of the ingredients.
tell your doctor if you are taking or have recently taken riociguat (Adempas) or a phosphodiesterase inhibitor (PDE-5) such as avanafil (Stendra), sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis), and vardenafil (Levitra, Staxyn). Your doctor will probably tell you not to take isosorbide if you are taking one of these medications.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: aspirin; beta blockers such as atenolol (Tenormin, Tenoretic), carteolol , labetalol (Trandate), metoprolol (Lopressor, Toprol-XL, in Dutoprol, in Lopressor HCT), nadolol (Corgard, in Corzide), propranolol (Hemangeol, Inderal, Innopran), sotalol (Betapace, Sorine, Sotylize), and timolol; calcium channel blockers such as amlodipine (Norvasc, in Amturnide, in Tekamlo), diltiazem (Cardizem, Cartia, Dilt-CD, others), felodipine (Plendil), isradipine, nifedipine (Adalat CC, Afeditab, Procardia), and verapamil (Calan, Covera, Verelan); ergot-type medications such as bromocriptine (Cycloset, Parlodel), cabergoline, dihydroergotamine (D.H.E. 45, Migranal), ergoloid mesylates (Hydergine), ergotamine (in Cafergot, in Migergot), methylergonovine (Methergine), methysergide (Sansert; no longer available in the U.S.), and pergolide (Permax; no longer available in the U.S.); medications for high blood pressure, heart failure, or an irregular heartbeat. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you may be dehydrated, if you have recently had a heart attack, or if you have or have ever had heart failure, low blood pressure, or hypertrophic cardiomyopathy (thickening of the heart muscles).
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking isosorbide, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking isosorbide.
ask your doctor about the safe use of alcoholic beverages while you are taking isosorbide. Alcohol can make the side effects from isosorbide worse.
you should know that isosorbide may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position, or at any time, especially if you have been drinking alcoholic beverages. To avoid this problem, get up slowly, resting your feet on the floor for a few minutes before standing up. Take extra precautions to avoid falling during your treatment with isosorbide.
you should know that you may experience headaches every day during your treatment with isosorbide. These headaches may be a sign that the medication is working as it should. Do not try to change the times or the way that you take isosorbide in order to avoid headaches because then the medication may not work as well. Your doctor may tell you to take a pain reliever to treat your headaches.