Take isosorbide mononitrate exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
This form of nitrate is used to reduce the number of angina attacks over a long time. It will not relieve an attack that has already started because it works too slowly. The extended-release form gradually releases medicine to provide its effect for 8 to 10 hours. Check with your doctor if you also need a fast-acting medicine to relieve the pain of an angina attack.
You should take isosorbide mononitrate first thing in the morning and follow the same schedule each day. Isosorbide mononitrate works best if you have a "drug-free" period of time every day when you do not take it. Your doctor will schedule your doses during the day to allow for a drug-free time. Follow the schedule of dosing carefully so the medicine will work properly.
Swallow the extended-release tablet whole with a half glass of water. Do not split, crush, or chew it.
Dosing
The dose of isosorbide mononitrate will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of isosorbide mononitrate. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
For prevention of angina:
For oral dosage form (extended-release tablets):
Adults—At first, 30 or 60 milligrams (mg) once a day. Take the dose in the morning right after you wake up. Your doctor may increase your dose as needed.
Children—Use and dose must be determined by your doctor.
For oral dosage form (tablets):
Adults—20 milligrams (mg) two times a day. Take the first dose in the morning right after you wake up, and the second dose 7 hours later.
Children—Use and dose must be determined by your doctor.
Missed dose
If you miss a dose of isosorbide mononitrate, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Storage
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
 Detailed Isosorbide mononitrate dosage information
