Glyceryl trinitrate (spray)

Commonly called GTN spray

Easy-to-read medicine information about glyceryl trinitrate spray – what is it, how to use it safely and possible side effects. Glyceryl trinitrate spray is commonly called GTN spray.

Type of medicine Also called
  • Belongs to a group of medicines called nitrates
  • Used to treat chest pain (angina)
  • Glytrin®
  • Nitrolingual®
  • GTN spray

What is GTN spray?

GTN spray is used to relieve angina. Angina is chest pain which may spread to your throat, jaw, neck, shoulders or arms. Angina happens when the blood supply to the muscles of your heart are restricted, due to narrowing of the blood vessels supplying the heart.

GTN spray works by widening blood vessels, letting more blood and oxygen reach the heart which reduces strain on your heart, making it easier for the heart to pump blood. Read more about angina

GTN spray is sprayed under the tongue for quick onset. In this way, it provides rapid relief from angina symptoms. It can also be used for when angina pain is expected to happen, such as before exercise that is likely to cause chest pain (for example, before climbing stairs).

In New Zealand, GTN spray is available on prescription from your doctor. You can also buy GTN spray from your pharmacy without a prescription, after consultation with your pharmacist. 


If you experience chest pain (angina), chest ache or chest discomfort, you should:

  • Stop what you are doing sit down and rest. Use one spray under your tongue and wait 5 minutes.
  • If your angina is relieved by rest or your spray, you can resume your activities gently.
  • If the pain is still present, use another spray and wait 5 minutes.
  • If the pain is still present, call 111 and ask for an ambulance.   


To avoid chest pain before doing some activities (like exercise): 1 spray under the tongue 5–10 minutes before the activity.

How to use GTN spray

  • If possible, it is recommended that you sit down when using GTN spray.
  • Remove the cap. Hold the canister upright with the forefinger on top of the white button. There is no need to shake the canister.
  • Open your mouth and bring the spray nozzle as close as possible, aiming it under the tongue. Press the button firmly, directing the spray under the tongue while holding your breath.
  • Keep the button held down until all the dose has been released. Close your mouth immediately but do not inhale the spray.
  • If necessary, repeat for a second time following the steps above.
  • No more than two doses are recommended at one time.
  • Always replace the cap after use.
  • You may feel a slight tingling in your mouth when you use GTN spray. This is harmless.

Other handy tips

  • Keep your GTN spray with you at all times: make sure you have your GTN spray with you at all times so you know where it is when you need it and don't hesitate to use it.
  • Keep a spare GTN spray handy: make sure you get a new one before the old one runs out.
  • Sit down before using GTN spray because it can make you feel light-headed and dizzy.
  • Check the expiry date written on the canister. After this date the spray may not work, so you will need to get a new
  • Storage: you can carry the spray in your pocket but it needs to be stored below 25ºC, so don't keep it in your car during summer.

Precautions – before using GTN spray

  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have low blood pressure?
  • Have you recently had a heart attack?
  • Are you are taking or using any other medicines? This includes any medicines you are using that are available to buy from a pharmacy, supermarket or natural health store without a prescription.  If so, it’s important that you tell your doctor or pharmacist before getting a GTN spray. Sometimes a medicine isn’t suitable for a person with certain conditions or it can only be used with extra careIt is particularly important that you tell your doctor or pharmacist if you are using any medicines to help treat erectile dysfunction.

Do not use GTN spray if you are taking medicines used to treat erection problems, such as:

  • sildenafil (Viagra, Avigra, Vedafil, Silvasta)
  • tadalafil (Cialis)
  • vardenafil (Levitra).

Using erectile dysfunction medicine with GTN spray can cause a sudden decrease in blood pressure, which can be life-threatening.

Possible side effects

Like all medicines, GTN spray can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Headache
  • This is quite common when you use GTN spray and should settle after a few days.
  • Tell your doctor if it is ongoing 
  • Dizziness
  • Feeling lightheaded
  • Feeling faint when you stand up
  • This is quite common when you use GTN spray and usually goes away with time.
  • Sit down when using the spray.
  • Avoid alcohol.
  • Tell your doctor if this continues.
  • Changes in your heartbeat (either fast, slow or irregular)
  • Tell your doctor.
  • An allergic reaction such as skin rash, itching, swelling of your lips, face and mouth or difficulty breathing, such as chest tightness or wheezing
  • Tell your doctor immediately or ring HealthLine 0800 611 116.


GTN spray can interact with a few medications and herbal supplements so check with your doctor or pharmacist before starting GTN spray or before starting any new medicines. GTN spray interacts with medicines to treat erectile problems such as sildenafil (Viagra, Avigra, Vedafil, Silvasta), tadalafil (Cialis) and vardenafil (Levitra).

Learn more

The following links have more information on GTN spray.

Glyceryl trinitrate (spray) New Zealand Formulary Patient Information


  1. Glyceryl trinitrate (systemic) New Zealand Formulary
Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 03 Jun 2019