In this drug factsheet:
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 lying or sitting position
- fast heartbeat
- flushing of the face and neck
- nausea or vomiting
- runny nose
- sore throat or mouth
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- blurred vision
- dryness of mouth
- headache (severe or prolonged)
- signs of low blood pressure (e.g., dizziness, lightheadedness, fainting)
- swelling of the ankles
- tingling or pins and needles of the arms or legs
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 head
- shortness of breath
- unusual tiredness or weakness
- weak and fast heartbeat
Stop taking the medication and seek immediate medical attention if any of the following occur:
- signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- continued chest pain
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.
Dizziness: This treatment may cause temporary dizziness. Do not drive, operate machinery, or perform other hazardous tasks until you have determined how this medication affects you.
Low blood pressure: Headaches or symptoms of low blood pressure, such as weakness or dizziness, particularly when getting up suddenly from a lying or sitting position, may result from taking too much nitroglycerin. If these symptoms occur, your doctor may reduce the dose or stop the use of nitroglycerin. People who might be negatively affected by low blood pressure should use nitroglycerin spray with caution. People who take diuretics or have pre-existing low blood pressure may be at more risk of experiencing low blood pressure. Discuss any concerns you might have with your doctor.
Medical conditions: The benefits and safety of nitroglycerin spray for people who have an acute heart attack or congestive heart failure have not been established.
Tolerance: Nitroglycerin users may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also happen, especially if long-acting nitrates are being used at the same time. As tolerance to nitroglycerin develops, the effect of fast-acting sublingual (under the tongue) nitroglycerin is somewhat reduced.
Pregnancy: This medication has not been studied for use by pregnant women. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: It is not known whether this medication 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:
- barbiturates (e.g., butalbital, phenobarbital)
- ergot alkaloids (e.g., dihydroergotamine, ergotamine, methylergonavine)
- medications that reduce blood pressure (e.g., vasodilators, calcium channel blockers, ACE inhibitors, beta-blockers, diuretics)
- phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
- tricyclic antidepressants (e.g., amitriptyline, imipramine, nortriptyline)
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.