glycerin

Therapeutic Classification: antiglaucoma agents, laxatives

Pharmacologic Classification: osmotics

Indications ⬆ ⬇

REMS

Treatment of constipation.
Reduction of corneal edema.

Action ⬆ ⬇

Draws water into the lumen of the colon.
Osmotically draws water from extravascular spaces, including the eye, into intravascular compartment.

Therapeutic effects:

Relief of constipation.
Reduction of corneal edema.

Pharmacokinetics ⬆ ⬇

Absorption: Not significantly absorbed from colonic mucosa.

Distribution: Remains in the intravascular space.

Metabolism/Excretion: 80% metabolized by the liver, 10–20% metabolized by the kidneys.

Half-Life: 30–45 min.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
Rect (laxative effect)	unknown	15–30 min	unknown

Ophth (reduced corneal swelling)	unknown	unknown	3–4 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity.

Use Cautiously in:

Severe dehydration;
Geriatric patients (increased risk of dehydration).

Adv. Reactions/Side Effects ⬆ ⬇

F and E: dehydration

GI: diarrhea, nausea, cramping, vomiting

Neuro: headache, confusion

Misc: thirst

Interactions ⬆ ⬇

Drug-drug:

None known.

Route/Dosage ⬆ ⬇

Laxative

Reduction of Corneal Edema

(Adults and Children >6 yr): 1 adult suppository 1–2 times/day as needed or 5–15 mL as an enema.
(Children <6 yr): 1 infant suppository 1–2 times/day as needed or 2–5 mL as an enema.
(Adults and Children ): 1–2 drops in eye(s) prior to examination or 1–2 drops in eye(s) every 3–4 hr for lubricant effect.

Availability ⬆ ⬇

(Generic available)

Suppositories: Adult^OTC; pediatric^OTC
Liquid for rectal pediatric use: 4-mL applicators^OTC
Ophthalmic solution: 15-mL containers^OTC

Assessment ⬆ ⬇

Laxative: Assess patient for abdominal distention, presence of bowel sounds, and normal pattern of bowel function.
- Assess color, consistency, and amount of stool produced.

Lab Test Considerations:

May cause slightly elevated serum and urine glucose concentrations.

Implementation ⬆ ⬇

Glycerin suppository or enema usually causes evacuation of the colon in 15–30 min.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take glycerin as directed. Do not take more than the amount prescribed.
Laxative: Advise patient that laxatives should be used only for short-term therapy. Long-term therapy may cause electrolyte imbalance and dependence.
- Caution patients not to use laxatives when abdominal pain, nausea, vomiting, or fever is present.

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Pronunciation ⬇

Classifications ⬆ ⬇