Glycerin

Occasional Constipation (Rectal)

• Suppository: Insert one 2g or 3g suppository rectally once daily as needed. Usually, a bowel movement occurs within 15 to 60 minutes.
• Liquid Enema: One 4-mL unit rectally once daily.

Occasional Constipation (Rectal)

• Children 2 to 6 years: One 1g to 1.5g pediatric suppository rectally once daily as needed.
• Children under 2 years: Use only as directed by a pediatrician.

Renal Impairment

No specific dose adjustments are required for rectal use. For systemic (oral) use, caution is advised in patients with severe renal disease due to potential fluid shifts.

Hepatic Impairment

No dosage adjustments are typically necessary for topical or rectal administration.

Elderly Patients

Elderly patients should use laxatives with caution to avoid dehydration or electrolyte imbalances. Healthcare providers often recommend starting with the lowest effective dose.

• Rectal Suppositories: Wash hands before and after use. Remove the foil wrapper. Moisten the suppository with lukewarm water. Lie on your left side with knees bent. Gently insert the suppository pointed-end first into the rectum. Remain lying down for 15 minutes to allow the medication to work.
• Topical: Apply to the affected area as needed, usually after bathing while the skin is still damp.
• Storage: Store at room temperature away from heat and direct sunlight. Keep suppositories in a cool place to prevent melting.

Glycerin is typically used on an "as-needed" basis. If your healthcare provider has prescribed a regular schedule and you miss a dose, take it as soon as you remember. If it is almost time for the next dose, skip the missed dose. Do not double the dose.

Signs of rectal overdose may include severe rectal pain, persistent diarrhea, or dehydration. If oral glycerin is ingested accidentally in large amounts, symptoms may include headache, nausea, vomiting, or confusion. Seek emergency medical attention or contact a Poison Control Center immediately.

> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.

When used rectally, common side effects are usually localized and temporary. These may include:

• Rectal Irritation: A mild burning or stinging sensation immediately after insertion.
• Abdominal Cramping: Mild discomfort as the bowel is stimulated to move.
• Tenesmus: A frequent urge to evacuate the bowels without success.

• Diarrhea: Excessive bowel movements if used too frequently.
• Nausea: Occasional stomach upset following rectal administration.
• Skin Redness: When used topically, mild erythema (redness) may occur in sensitive individuals.

• Severe Allergic Reactions: Including rash, itching, or swelling of the face and throat.
• Dehydration: Primarily a risk with excessive oral or systemic use.

> Warning: Stop using Glycerin and call your doctor immediately if you experience any of these:

• Rectal Bleeding: Any sign of bright red blood in the stool or on the suppository.
• Severe Abdominal Pain: Sharp or persistent pain that does not resolve after a bowel movement.
• No Bowel Movement: Failure to have a bowel movement after use may indicate a more serious underlying condition like a bowel obstruction.
• Signs of Dehydration: Extreme thirst, very dark urine, dizziness, or fainting.

Prolonged use of Glycerin suppositories may lead to "laxative dependence," where the bowels require a stimulant to function normally. It may also cause chronic proctitis (inflammation of the rectal lining) in rare cases of extreme overuse.

No FDA black box warnings have been issued for Glycerin. It is generally considered a low-risk medication when used according to label instructions.

Report any unusual symptoms to your healthcare provider.

Glycerin should only be used for short-term relief. If symptoms of constipation persist for more than seven days, consult a healthcare professional. It is important to maintain adequate fluid intake while using any osmotic laxative to prevent dehydration.

No FDA black box warnings for Glycerin.

• Allergic Reactions: Patients with a known hypersensitivity to glycerin or any components of the formulation should avoid use. Anaphylaxis is extremely rare but possible.
• Pre-existing Conditions: Patients with undiagnosed abdominal pain, nausea, vomiting, or fever should not use glycerin until a doctor has ruled out serious conditions like appendicitis or bowel obstruction.
• Rectal Health: Use with caution in patients with rectal fissures, hemorrhoids, or ulcerative colitis, as the local irritant effect may cause discomfort.

Routine lab monitoring is generally not required for topical or rectal glycerin. However, in patients using systemic glycerin for pressure reduction, healthcare providers may monitor:

• Electrolyte Levels: Sodium and potassium balance.
• Renal Function: Serum creatinine and BUN.
• Hydration Status: Clinical signs of fluid volume.

Glycerin is not known to impair the ability to drive or operate machinery when used rectally or topically.

There are no known direct interactions between alcohol and rectal/topical glycerin. However, alcohol can contribute to dehydration, which may worsen constipation.

There is no requirement for tapering when discontinuing glycerin. However, if you have been using it daily for an extended period, you should discuss a plan with your doctor to restore natural bowel habits.

> Important: Discuss all your medical conditions with your healthcare provider before starting Glycerin.

There are no medications that are strictly contraindicated for use with rectal or topical Glycerin. However, Glycerin should not be used simultaneously with other rectal products unless directed by a physician, as this may interfere with absorption or cause excessive irritation.

• Diuretics (Water Pills): When Glycerin is used systemically (orally), it can have additive effects with diuretics like furosemide, potentially leading to significant dehydration or electrolyte imbalances. This is less of a concern with rectal use.

• Other Laxatives: Using multiple laxatives simultaneously increases the risk of diarrhea and electrolyte depletion. Use only one type of laxative at a time unless otherwise instructed by a healthcare provider.

There are no known significant food interactions with Glycerin. For patients treating constipation, a high-fiber diet and increased water intake are recommended to complement the medication's effects.

• Aloe/Senna/Cascara: Use caution when combining Glycerin with herbal stimulant laxatives, as this may cause excessive cramping and bowel urgency.

• Blood Glucose: In diabetic patients, large systemic doses of Glycerin may theoretically affect blood glucose readings, as Glycerin is metabolized into glucose. This is not expected with rectal or topical use.

For each major interaction, the primary mechanism is often pharmacodynamic (additive effects on the bowel or fluid balance). The clinical consequence is usually an increased risk of side effects like diarrhea or dehydration. Management involves using the lowest effective dose and monitoring clinical response.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.

• Hypersensitivity: Known allergy to Glycerin or any inactive ingredients in the product.
• Bowel Obstruction: Glycerin must never be used if a mechanical bowel obstruction is suspected, as stimulating the bowel against an obstruction can lead to perforation.
• Undiagnosed Abdominal Pain: Use is contraindicated when the cause of abdominal pain, nausea, or vomiting is unknown, as these may be signs of a condition requiring surgery (e.g., appendicitis).

• Severe Dehydration: Systemic use should be avoided in patients who are already severely dehydrated.
• Cardiac Disease: Patients with congestive heart failure should use systemic glycerin with caution due to potential fluid shifts.
• Diabetes: Use with caution in diabetic patients if administered orally, due to the metabolic conversion to glucose.

There is no significant evidence of cross-sensitivity between Glycerin and other classes of laxatives or emollients. However, patients sensitive to other polyols (like sorbitol) should monitor for similar local irritation.

> Important: Your healthcare provider will evaluate your complete medical history before prescribing Glycerin.

FDA Pregnancy Category: C (Rectal/Topical). Glycerin is generally considered safe for occasional use during pregnancy when administered rectally or topically, as systemic absorption is minimal. However, it should only be used if clearly needed and under the advice of a healthcare provider. There is no evidence of teratogenicity (birth defects) associated with standard use.

Glycerin is not expected to pass into breast milk in significant quantities following rectal or topical application. It is generally considered compatible with breastfeeding. Always consult a healthcare provider before use while nursing.

Glycerin suppositories are frequently used in children as young as 2 years old for occasional constipation. For children under 2, a healthcare provider must be consulted. It is important to use the specific "pediatric" or "infant" sized suppositories to ensure the correct dose.

Older adults may be more sensitive to the effects of laxatives. There is an increased risk of electrolyte imbalance if used excessively. Clinical guidelines suggest that lifestyle modifications (fiber, fluid, exercise) should be the first line of treatment in the elderly, with glycerin used as a secondary, short-term option.

No dose adjustment is needed for rectal use. Patients with chronic kidney disease (CKD) should avoid frequent use of any laxative without medical supervision to prevent fluid-electrolyte disturbances.

No specific adjustments are required for patients with liver disease for the standard rectal or topical routes of administration.

> Important: Special populations require individualized medical assessment.

Glycerin acts as a Hyperosmotic Agent. In the rectum, it exerts an osmotic effect that draws water into the lumen. This increases the osmotic pressure and volume of the stool, which mechanically stimulates the rectal stretch receptors and initiates the defecation reflex. Topically, it acts as a humectant by forming hydrogen bonds with water molecules, drawing them into the skin's layers.

The onset of action for rectal Glycerin is rapid, typically occurring within 15 to 60 minutes. It does not have a significant systemic dose-response relationship when used rectally because its action is local. Tolerance is generally not a concern with occasional use, but the body may become dependent on the stimulus for bowel movements with chronic use.

| Parameter | Value |

|---|---|

| Bioavailability | High (Oral); Minimal (Rectal/Topical) |

| Protein Binding | Negligible |

| Half-life | 30–45 minutes |

| Tmax | 1–1.5 hours (Oral) |

| Metabolism | Hepatic (to glucose/glycogen) |

| Excretion | Renal (7-14% unchanged) |

• Molecular Formula: C3H8O3
• Molecular Weight: 92.09 g/mol
• Solubility: Miscible with water and alcohol; insoluble in oils.
• Structure: A trihydroxy sugar alcohol consisting of a propane chain with a hydroxyl group on each carbon.

Glycerin belongs to the Osmotic Laxative and Emollient therapeutic classes. Related medications in the osmotic laxative class include Sorbitol, Polyethylene Glycol (Miralax), and Lactulose.