Generic Name: nitroglycerin (nye-troe-GLIS-er-in)
Medically reviewed by Drugs.com. Last updated on Jan 26, 2021.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Colorectal Agent
Chemical Class: Nitrate
Uses for nitroglycerin
Nitroglycerin rectal ointment is used to relieve moderate to severe pain caused by chronic anal fissures. An anal fissure is a tear in the skin around the opening for bowel movements, also known as the anus or rectal area. Nitroglycerin belongs to the group of medicines called nitrates. It works to relax the muscles around the anus so there is less pressure in the area.
Nitroglycerin is available only with your doctor's prescription.
Before using nitroglycerin
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For nitroglycerin, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to nitroglycerin or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of nitroglycerin in the pediatric population. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of nitroglycerin in the elderly. However, elderly patients are more likely to have unwanted effects such as lightheadedness, dizziness, or fainting, which may require caution and an adjustment in the dose for patients receiving nitroglycerin.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking nitroglycerin, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using nitroglycerin with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using nitroglycerin with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Alteplase, Recombinant
Using nitroglycerin with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Other medical problems
The presence of other medical problems may affect the use of nitroglycerin. Make sure you tell your doctor if you have any other medical problems, especially:
- Anemia, severe or
- Increased pressure in the head from an injury or bleeding—Should not be used in patients with these conditions.
- Congestive heart failure or
- Heart attack, recent or
- Heart or blood vessel disease (eg, cardiomyopathy) or
- Hypotension (low blood pressure) or
- Hypovolemia (low amount of blood)—Use with caution. May cause side effects to become worse.
Proper use of nitroglycerin
Use nitroglycerin only as directed by your doctor. Do not use more of it, do not use it more often, and do not use it for a longer time than your doctor ordered.
Nitroglycerin is for rectal use only. Do not get it in your eyes, nose, mouth, or vagina. If it does get in these areas, rinse it off right away.
To apply the ointment:
- Wash your hands before using the medicine.
- Cover your finger with a plastic wrap, disposable surgical glove, or finger cot.
- Lay the covered finger next to the dosing line on the side of the medicine box. The tip of your finger should be at one end of the dosing line.
- Squeeze the ointment onto your finger. The amount of medicine should be the same length as the dosing line.
- Gently insert your finger with the ointment into the anal canal. Do not push your finger past the first finger joint.
- Carefully apply the ointment around the inner sides of the anal canal.
- If you have too much pain in the anal canal, apply the ointment directly to the skin on the outside.
- Throw the finger covering in the garbage and wash your hands.
The dose of nitroglycerin will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of nitroglycerin. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For rectal dosage form (ointment):
- For pain caused by anal fissures:
- Adult—Apply 1 inch into the anus every 12 hours.
- Children—Use and dose must be determined by your doctor.
- For pain caused by anal fissures:
If you miss a dose of nitroglycerin, apply it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep the tube tightly closed after you use the medicine. Throw away any unused medicine 8 weeks after opening the tube for the first time.
Precautions while using nitroglycerin
It is very important that your doctor check your progress at regular visits to make sure nitroglycerin is working properly and to check for unwanted effects.
Do not take sildenafil (Viagra®), tadalafil (Cialis®), or vardenafil (Levitra®) while you are using nitroglycerin. Using these medicines together may cause blurred vision, dizziness, lightheadedness, low blood pressure, or fainting.
Nitroglycerin may cause headaches. The headaches are a sign that the medicine is working. Do not stop using the medicine or change how you use it to avoid the headaches. If you have questions about this, talk with your doctor.
Dizziness, lightheadedness, or fainting may occur, especially when you get up quickly from a lying or sitting position. Getting up slowly will help. You should also limit the amount of alcohol you drink to prevent more dizziness. If you have questions about this, talk with your doctor.
Nitroglycerin may make you dizzy or lightheaded. Avoid driving, using machines, or doing anything else that could be dangerous if you are dizzy.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Nitroglycerin side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Bluish-colored lips, fingernails, or palms
- dark urine
- difficulty with breathing
- difficulty with swallowing
- fast heartbeat
- feeling of warmth
- pale skin
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- redness of the face, neck, arms, and occasionally, upper chest
- shortness of breath
- skin rash
- tightness in the chest
- unusual bleeding or bruising
- unusual tiredness or weakness
Incidence not known
- Blurred vision
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Dizziness or lightheadedness
Incidence not known
- Cracks in the skin
- loss of heat from the body
- red, swollen skin
- scaly skin
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
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