GTN (glyceryl trinitrate) | Medicines A–Z

Also sold asGlytrin, Coro-Nitro, Nitrolingual

Type of medicineNitrate

Available asSublingual spray, sublingual tablets, patches, ointment

How you get itPrescription only

GTN widens blood vessels and relieves angina within minutes. Knowing exactly what to do during an attack — and at what point to stop waiting and call an ambulance — is the most useful thing on this page.

Using it during an attack

Sit down first — GTN can make you dizzy or faint. Then:

Use one or two sprays under the tongue, or dissolve a tablet under the tongue. Do not swallow.
Wait five minutes.
If the pain is still there, take a second dose.
Wait another five minutes.

If the pain has not gone five minutes after the second dose — call 999. Do not wait longer, do not drive yourself, and tell the ambulance crew you have taken GTN, because they must avoid certain other treatments. Chew an aspirin 300mg while waiting unless you are allergic or have been told not to.

GTN can also be used a few minutes before something you know brings on angina, such as walking uphill.

The interaction that matters

Never use GTN with sildenafil, tadalafil or vardenafil (Viagra, Cialis, Levitra) or with recreational “poppers”. The combination causes a catastrophic drop in blood pressure and can be fatal. If you have taken one of those, tell any medical team treating you.

Practical points

Headache, flushing and dizziness after a dose are common and expected — the headache often eases with continued use, and paracetamol helps.

Sublingual tablets have a short shelf life once opened, usually eight weeks — write the opening date on the bottle. Sprays last longer; check the expiry.

Carry it with you at all times. If you find you are using it more often than usual, or it is working less well, tell your GP — that can signal worsening angina.

Patches and ointment are used differently, with a nitrate-free period each day to prevent tolerance; follow your specific instructions.

Always read the label. This page is general information, not advice for your situation. Doses, warnings and interactions differ between products and between people. Check the leaflet inside your medicine, and ask our pharmacist if anything is unclear — that conversation is free and takes two minutes.

Questions about GTN (glyceryl trinitrate)?

1 Lyng Lane, West Bromwich B70 7RW · Mon–Fri 8:30am–6pm, Sat 9am–1pm · 0121 500 5756

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Frequently asked questions

When should I call 999 during an angina attack?

If pain persists five minutes after a second GTN dose. Do not wait longer or drive yourself, and tell the crew you have taken GTN.

What must I never take with GTN?

Sildenafil, tadalafil, vardenafil or recreational poppers. The combination causes a dangerous drop in blood pressure and can be fatal.

Why does GTN give me a headache?

It widens blood vessels, which commonly causes headache and flushing. It often eases with continued use, and paracetamol helps.

How long do GTN tablets last once opened?

Usually about eight weeks. Write the opening date on the bottle. Sprays last longer — check the expiry.

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GTN Spray and Tablets