NitratePrescription only
Isosorbide Mononitrate
Tablet
Quick Summary
It relaxes blood vessels and reduces how hard the heart works.
Angina prevention
Medical Uses
Angina prevention: Daily use.
How it's taken
Take as prescribed; a daily nitrate-free period helps it keep working.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Headache
Common at first.
Dizziness
Sometimes.
Flushing
Sometimes.
Interactions
Sildenafil and tadalafil
Dangerous drop in blood pressure.
Critical Warnings
Erectile dysfunction medicines
Black Box Warning: Never combine.
Not for attacks
Use GTN for quick relief.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Isosorbide: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine