How does this medication work? What will it do for me?
Nitroglycerin belongs to the class of medications called antianginals. Nitroglycerin patches are used alone or in combination with other medications to prevent angina attacks (chest pain). Nitroglycerin reduces the number of angina attacks by relaxing blood vessels and increasing the oxygen and blood supply to the heart. The nitroglycerin patch is not intended for immediate relief of angina.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Each 10 cm2 patch contains 40 mg of nitroglycerin released at 0.2 mg per hour.
Each 20 cm2 patch contains 80 mg of nitroglycerin released at 0.4 mg per hour.
Each 30 cm2 patch contains 120 mg of nitroglycerin released at0.6 mg per hour.
Each 40 cm2 patch contains 160 mg of nitroglycerin released at 0.8 mg per hour.
How should I use this medication?
The usual dose of nitroglycerin patches varies according to need. The patch is usually applied in the morning and taken off 12 to 14 hours later (leaving 10 to 12 hours overnight without the patch).
The patch may be applied to any convenient skin area – recommended sites include the upper arm, back, shoulders, or chest. Use a different application site each time. A suitable area may be shaved if necessary. Do not apply the patch to the ends of the arms or legs. Wash your hands thoroughly after application. Following use, discard the patch in a manner that prevents accidental application or ingestion by curious pets or children.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.
It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, apply a patch as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not apply a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.
Store this medication at room temperature and keep it out of the reach of children.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not use this medication if you:
- are allergic to nitroglycerin or any ingredients of the medication
- are allergic to the adhesive used in nitroglycerin patches
- are allergic to other nitrates or nitrites
- have acute circulatory failure associated with severe lowering of blood pressure (states of collapse or shock)
- have extremely low blood pressure
- have increased eye pressure (glaucoma)
- have increased pressure within the head (e.g., after an accident)
- have reduced heart function due to obstruction (e.g., narrowing of the heart valves)
- have severe anemia
- have severe dizziness when getting up from a sitting or lying down position
- are using the erectile dysfunction medications called PDE-5 inhibitors (e.g., sildenafil, tadalafil or vardenafil)
- are taking the medication riociguat
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- dizziness or lightheadedness, especially when getting up from a sitting or lying down position
- fast, slow, or irregular heartbeat
- flushing of the face and neck
- sore, reddened skin where the patch was applied
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- blurred vision
- dry mouth
- headache (severe or prolonged)
Stop taking the medication and seek immediate medical attention if any of the following occur:
- signs of signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
- signs of methemoglobinemia (e.g., shortness of breath, blue to purplish lips, fingers or toes, severe headache, fatigue, dizziness or loss of consciousness)
Contact a doctor at once if any of the following signs of overdose occur:
- bluish-coloured lips, fingernails, or palms of the hands
- convulsions (seizures)
- dizziness (extreme) or fainting
- feeling of extreme pressure in the head
- shortness of breath
- unusual tiredness or weakness
- weak and fast heartbeat
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Acute angina attacks: Nitroglycerin patches are not intended for immediate relief of acute attacks of angina. Sublingual (under the tongue) nitroglycerin preparations (spray or tablets) should be used for this purpose.
Dizziness/reduced alertness: People using this medication may experience faintness or dizziness and reduced reaction time when driving or operating machinery, especially at the start of treatment. Avoid these and other hazardous tasks until you have determined how this medication affects you.
Heart disease: The benefits and safety of using the nitroglycerin patch have not been established for people who have had an acute heart attack or have congestive heart failure.
Low blood pressure: Headaches or symptoms of low blood pressure such as weakness or dizziness, particularly when getting up suddenly from a sitting or lying down position, may result from taking too much nitroglycerin. If these symptoms occur, your doctor may reduce the dose or have you stop using the nitroglycerin patch. People who might be negatively affected by low blood pressure should use this medication with caution. If you take diuretics or have preexisting low blood pressure, you may be at an increased risk of experiencing this effect.
Symptom changes: If your symptoms of angina increase at any time (including during the period of the day that you aren't taking the medication), be sure to tell your doctor.
Tolerance: People who use nitroglycerin may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also happen, especially if a medication-free period is not observed each day. As tolerance to nitroglycerin patches develops, the effect of fast-acting sublingual (under the tongue) nitroglycerin is also somewhat reduced.
Pregnancy: This medication has not been studied for use by pregnant women. Be sure to tell your doctor if you are pregnant or planning to become pregnant. If you become pregnant while using this medication inform your doctor as soon as possible.
Breast-feeding: It is not known if nitroglycerin passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of this medication for children have not been established.
What other drugs could interact with this medication?
There may be an interaction between nitroglycerin and any of the following:
- alpha blockers (e.g., alfuzosin, doxazosin, tamsulosin)
- alpha agonists (e.g., clonidine, methyldopa)
- angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
- angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
- barbiturates (e.g., butalbital, pentobarbital phenobarbital)
- beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
- calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
- diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
- ergot alkaloids (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
- other nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
- phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
- sodium nitrite
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.