NitrateAngina relief
Glyceryl Trinitrate (GTN)
Spray or tablet under the tongue
Quick Summary
GTN widens blood vessels, reducing the heart's workload within minutes.
Angina attacks
Before exertion
Medical Uses
Angina attacks: Quick relief.
Before exertion: To prevent angina.
How it's taken
Sit down before using it. If pain isn't better 5 minutes after the second use, call 112.
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
Very common.
Dizziness
Sit down.
Flushing
Sometimes.
Interactions
Sildenafil and tadalafil
Can cause a dangerous drop in blood pressure; never combine.
Critical Warnings
Chest pain not relieved
Black Box Warning: Call 112.
Erectile dysfunction medicines
Black Box Warning: Never take together.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Nitroglycerin Sublingual: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine