GTN Spray should be taken at the first sign of chest pain. It should be used in the dose and duration as advised by your doctor. Seek medical help immediately if your chest pain continues for more than 15 minutes. Some people may be advised to use this medicine prior to any exertional activity or exercise, which may precipitate angina.
The most common side effect of this medicine is a headache which may be severe. This can sometimes be helped by drinking plenty of fluids and avoiding alcohol. You may also experience lightheadedness, which could increase your risk of having a fall.
Do not use this medicine if you are taking medicines to treat high blood pressure in your lungs (pulmonary hypertension), or erectile dysfunction or if you have anemia or glaucoma (increased pressure inside the eye).