Glyceryl Trinitrate (GTN) 400mcg spray is a medication used to relieve symptoms of chest pain (angina). Here?s how you use it:
At the onset of an attack, one or two 400 microgram metered doses (sprays) should be sprayed under the tongue.

If symptoms do not resolve, this dose may be repeated at five-minute intervals for a total of three doses (sprays).
If symptoms have not resolved after a total of three doses (sprays), the patient should seek prompt medical attention.
It?s important to sit down before using GTN, as you may experience headaches, flushing, or dizziness soon after use. Always keep your GTN spray with you and keep a spare one handy.

Please note that this information is a general guide, and you should always follow the instructions provided by your doctor or pharmacist. If you have any concerns or questions about your medication, please consult with a healthcare professional.