Glyceryl trinitrate is an organic nitrate that donates nitric oxide

Do not rub this ointment into the skin. Use this ointment exactly as prescribed by your health care professional.

If you notice any of the symptoms listed below or any other symptoms which seem severe/persistent contact your doctor immediately.
a feeling of extreme pressure in the head
blurred vision
dry mouth
flushing of the face/neck
headache
irregular heartbeat/palpitations
nausea
skin irritation from application of the ointment
skin rash/itching/hives
sweating
swelling of the face/lips/tongue
unusual weak/tired feeling
vomiting

Inform your doctor if you are allergic to the formulation of this medication or any other medication in any other form.
alteplase
aspirin
certain migraine medicines(like ergotamine/DHE)
heparin
medication for high blood pressure
medication for mental depression
medicines for treatment of erectile dysfunction(sildenafil/tadalafil/vardenafil)
other medication used to treat angina
phenothiazines(chlorpromazine/mesoridazine/prochlorperazine/thioridazine)

If you suspect an overdose call the emergency department or your doctor immediately.

Do not double applications to make up for a missed application

Nitroglycerin ointment is an ideal treatment for anal fissure as one can avoid surgery. Nitroglycerin relaxes the anal sphincter muscle and provides immediate symptomatic relief in pain and spasm.

Store at room temperature between 59-86 degrees F (15-30 degrees C) away from heat and moisture.

Inform your doctor if you have or have ever had :
anaemia
bleeding in the brain
head injury/recent stroke
liver disease
previous heart attack