In the U.S.—

• Antiglaucoma agent, systemic
• Diuretic

Glycerin (GLI-ser-in) , 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.

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral
• Oral solution (U.S.)

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:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to glycerin. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies on effects in pregnancy have not been done in either humans or animals.

Breast-feeding—It is not known whether glycerin passes into breast milk. This medicine has not been reported to cause problems in nursing babies.

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

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

Other 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. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Diabetes mellitus (sugar diabetes)—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

It is very important that you take this medicine 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 this medicine, mix it with a small amount of unsweetened lemon, lime, or orange juice, pour over cracked ice, and sip through a straw.

Dosing—

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.

• 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 this medicine, 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.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

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

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

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 either of the following side effects occurs:

• Less common
  • Confusion 
  
  

• Rare
  • Irregular heartbeat 
  
  

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Headache;  nausea or vomiting 
  
  

• Less common
  • Diarrhea;  dizziness;  dryness of mouth or increased thirst 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, glycerin is used in certain patients with the following medical conditions:

• Cerebral edema (swelling of the brain)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.