Glycerin (Oral)

Jul 24, 2022

Commonly used brand name(s)

In the U.S.

  • Osmoglyn

In Canada

  • Glycerin

Available Dosage Forms:

  • Spray

Therapeutic Class: Protectant, Dental

Pharmacologic Class: Diuretic, Osmotic

Uses for glycerin

Glycerin , when taken by mouth, is used to treat certain conditions in which there is increased eye pressure, such as glaucoma. It may also be used before eye surgery to reduce pressure in the eye.

Glycerin may also be used for other conditions as determined by your doctor.

Glycerin is available only with your doctor’s prescription.

Before using glycerin

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 glycerin, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to glycerin 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.


Although there is no specific information comparing use of glycerin in children with use in other age groups, glycerin is not expected to cause different side effects or problems in children than it does in adults.


Glycerin reduces water in the body, and there may be an increased risk that elderly patients taking it could become dehydrated.


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 glycerin, 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 glycerin 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.

  • Arsenic Trioxide

Using glycerin 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.

  • Licorice

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. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of glycerin. Make sure you tell your doctor if you have any other medical problems, especially:

  • Type 2 diabetes mellitus—Use of glycerin may increase the chance of dehydration (loss of too much body water)
  • Confused mental states or
  • Heart disease or
  • Kidney disease—Glycerin may make these conditions worse

Proper use of glycerin

It is very important that you take glycerin only as directed. Do not take more of it and do not take it more often than your doctor ordered.

To improve the taste of glycerin, mix it with a small amount of unsweetened lemon, lime, or orange juice, pour over cracked ice, and sip through a straw.


The dose of glycerin 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 glycerin. 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 oral dosage form (oral solution):
    • To lower pressure in the eye:
      • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 1 to 2 grams per kilogram (kg) (0.45 to 0.91 grams per pound) of body weight taken one time. Then, additional doses of 500 milligrams (mg) per kg (227 mg per pound) of body weight every six hours may be taken if needed.
      • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 1 to 1.5 grams per kg (0.45 to 0.68 grams per pound) of body weight taken one time. The dose may be repeated in four to eight hours if needed.

Missed dose

If you miss a dose of glycerin, take 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. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Precautions while using glycerin

Your doctor should check your progress at regular visits to make sure that glycerin is working properly.

In some patients, headaches may occur when glycerin is taken. To help prevent or relieve the headache, lie down while you are taking glycerin and for a short time after taking it. If headaches become severe or continue, check with your doctor.

Glycerin 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 as soon as possible if any of the following side effects occur:

Less common

  • Confusion


  • Irregular heartbeat

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:

More common

  • Headache
  • nausea or vomiting

Less common

  • Diarrhea
  • dizziness
  • dryness of mouth or increased thirst

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.

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