Expert advice for GTN Spray
Headache (‘nitrate headache’) may occur but should go away after a few days of continued treatment. You may develop tolerance to Gtn with time, meaning that the same dose may be less effective next time. Follow the prescribed dosing schedule to avoid this. Eat healthy (low-fat, high-fibre, low-sodium diet), quit smoking, limit alcohol intake, increase your physical activity, watch your weight, and reduce stress. Notify your doctor about other medicines (eg. sildenafil, tadalafil or vardenafil) that you are taking as Gtn may interact with them and cause a serious fall in blood pressure. This may lead to collapse, unconsciousness and could be fatal.

Q. How is glyceryl trinitrate topical taken/ what is glyceryl trinitrate ointment?
Glyceryl trinitrate topical can be taken in a number of ways- skin/rectal ointments, transdermal patches. Glyceryl trinitrate ointment is used in prevention of angina (chest pain due to reduced blood supply to heart) attack. It can also be used to treat anal fissure.