Glyceryl Trinitrate (GTN) belongs to a group of medicines known as nitrates. GTN patches are used to prevent angina (chest pain).
This medicine may be used to treat other conditions as decided by your doctor.
Apply GTN patch on your skin exactly as directed by your doctor or according to the instructions on the label. Do not use more or less than instructed by your doctor.
Do not apply patch on broken skin. Do not cut the patch. The release pattern of the medicine will be affected if you cut the patch. Do not use it for a longer period of time than instructed by your doctor.
Instructions for application:
- Remove the patch from the protective foil pouch and peel away half of the liner. Do not touch the sticky side with your fingers.
- Apply the patch to a clean, dry and hairless area. Apply the patch on your chest, upper stomach area, upper arm, shoulder or thigh. Make sure that the area of skin is not oily, cut, blistered or irritated. The skin should be free of any powder, creams or lotions. If the area of skin is hairy, you should shave the area at least 3 days before you apply the patch. Do not put the patch near the waistline or where your belt or clothes may rub against it.
- Peel away the other half of the liner. Press firmly on the skin for a few seconds to ensure that the patch stays on the skin.
- Apply the patch at around the same time every day.
- Replace the patch every 24 hours. Change the site of application every day to avoid skin irritation. For example, if you put the patch on your right hip on the first day, put it on your left hip on the second day, and so on. Do not apply the patch to the same area of skin more than once in 3-4 days.
- If this patch falls off, apply a new patch to a new area of skin and change the patch at the usual scheduled time. If the sides of the patch lift up, use a plaster or bandage to secure it to your skin.
- Throw away the used patch by folding the sticky sides together, put back in the empty pouch, and place it in a rubbish bin. Do not throw it into the toilet bowl. Wash your hands after disposing of the used patch.
GTN patches must be used regularly for it to be effective. Continue using GTN patches even when you feel better. Do not stop using it unless instructed by the doctor.
Apply the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to apply your medicine, let your doctor and pharmacist know.
Alert your doctor if you have the following conditions:
- history of heart problems e.g. pericarditis (inflammation of the heart), valve stenosis (narrowing of the heart valves), aortic stenosis (obstruction of arteries resulting to inability of heart to pump enough blood around the body), pericardial tamponade (fluid around the heart)
- increased pressure in the skull due to bleeding in the brain or head injury
- severe anaemia (low red blood cell count)
- low blood pressure
- glaucoma (increased pressure in the eye)
- cardiogenic shock (a serious heart condition caused by very low blood pressure)
as GTN patches may not be suitable for you.
DO NOT use GTN patches with medicines used to treat impotence and pulmonary arterial hypertension (high blood pressure in the blood vessels leading to the lungs). Please see the section “Can I take this with other medicines?” below for more information.
Inform your doctor if you have the following conditions:
- liver disease
- thyroid disease
- kidney disease
- lung disease
- a recent heart attack
Inform your doctor that you are using GTN patch if you are going for any of these procedures:
- magnetic resonance imaging (MRI)
- cardio conversion or cardioversion (a procedure to normalise the heart rhythm)
- diathermy (a procedure that involves high frequencies of electric current to generate heat)
GTN patch that contains metal components should be removed before you go for the procedure.
Let your doctor know if you are pregnant or breastfeeding.
This medicine may cause dizziness. If affected, do not drive or take part in any activity in which you need to be alert.
This medicine may cause your blood pressure to fall suddenly when you get up from a sitting or lying down position and you may feel giddy. To minimise this problem, stand up slowly.
Other side effects include any of the following: headache, nausea, vomiting and application site irritation.
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not use GTN with the following medicines:
- medicines used to treat impotence e.g. sildenafil, tadalafil, vardenafil
- riociguat (medicines used to manage high blood pressure in the arteries of the lungs)
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for high blood pressure e.g. enalapril, metoprolol, amlodipine
- medicines to treat mood disorder e.g. thioridazine, chlorpromazine
- dihydroergotamine (medicine for migraine)
- NSAIDs (medicine for pain and inflammation) e.g. aspirin ketoprofen, ibuprofen
This list does not include all medicines that may interact with GTN.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicine, supplements and medicines that you buy without a prescription.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.