What it is used for
- Relieving a sudden attack of angina chest pain
- Preventing angina before activity that usually triggers it
How it works
Glyceryl trinitrate quickly relaxes and widens blood vessels, easing the heart's workload and improving blood flow to the heart muscle. This relieves the chest pain of an angina attack within minutes.
How it is taken
Comes as a tablet or spray placed under the tongue, and also as skin patches or ointment for longer-acting use. The under-the-tongue forms act fast and are used at the start of an attack or just before triggering activity. Take it exactly as your doctor or pharmacist directs and follow the label; sit down when using it, as it can cause dizziness.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Headache
- Dizziness or light-headedness
- Flushing
- Fast heartbeat
- A brief tingling where the tablet or spray is placed
Serious effects — get help
- Fainting or severe dizziness
- Chest pain that does not improve after using it as directed (this may be a heart attack — seek emergency care)
- A very fast or irregular heartbeat
- Signs of a serious allergic reaction
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Erectile-dysfunction medicines such as sildenafil, tadalafil, and vardenafil (dangerous drop in blood pressure — do not combine)
- Other blood pressure medicines
- Riociguat
- Alcohol (added drop in blood pressure)
Who should take care
- Never use with erectile-dysfunction medicines such as sildenafil — the combination can cause a dangerous fall in blood pressure
- Sit down before using it to avoid falling from dizziness
- Know your clinician's advice on when to call emergency services if the pain does not ease
- Store the medicine as directed, as some forms lose strength over time
- Tell your clinician about very low blood pressure or recent heart attack