Usage
Polyethylene Glycol (PEG) and Propylene Glycol (PG) are commonly used in combination ophthalmic solutions for the temporary relief of burning and irritation due to dryness of the eye. They are also available as nasal sprays. Orally administered PEG 3350 is used as a laxative.
- Pharmacological Classification:
- Ophthalmic lubricant (eye drops)
- Laxative (oral PEG 3350)
- Mechanism of Action:
- Ophthalmic: PEG and PG work similarly to natural tears, lubricating the ocular surface and providing temporary relief from dryness and irritation. The combination can form a protective gel on the eye’s surface.
- Laxative (oral PEG 3350): PEG 3350 is an osmotic laxative. It works by drawing water into the intestines, which softens the stool and increases bowel movements.
Alternate Names
How It Works
- Pharmacodynamics (Ophthalmic): PEG and PG lubricate the ocular surface, reducing friction and irritation. They can also help stabilize the tear film and prevent evaporation, thus improving overall eye moisture.
- Pharmacokinetics (Ophthalmic): Minimal systemic absorption is expected with topical ophthalmic use.
- Pharmacodynamics (Laxative/Oral PEG 3350): PEG 3350 increases the water content of the stool by osmosis. This leads to softer stools and increased bowel movements.
- Pharmacokinetics (Laxative/Oral PEG 3350): Minimally absorbed from the gastrointestinal tract. Excreted primarily in the feces.
- Mode of Action/Receptor Binding/Enzyme Inhibition: PEG and PG do not have specific receptor binding, enzyme inhibition, or neurotransmitter modulation effects in their ophthalmic or laxative uses.
Dosage
Standard Dosage
Adults:
- Ophthalmic: Instill 1 or 2 drops in the affected eye(s) as needed, typically up to four times per day.
- Laxative (PEG 3350): 17 grams (one heaping tablespoon or one packet) dissolved in 120-240 mL of liquid once daily.
Children:
- Ophthalmic: Use as directed by a physician.
- Laxative (PEG 3350): Consult a physician for appropriate dosing in children younger than 17 years.
Special Cases:
- Elderly Patients: No specific dosage adjustments are typically necessary, but monitor for dehydration with oral PEG 3350.
- Patients with Renal Impairment: Caution is advised with oral PEG 3350 due to the potential risk of electrolyte imbalance.
- Patients with Hepatic Dysfunction: No specific dosage adjustments are typically necessary.
- Patients with Comorbid Conditions: Exercise caution in patients with gastrointestinal disorders (e.g., bowel obstruction, inflammatory bowel disease).
Clinical Use Cases
- Ophthalmic: Dry eye syndrome, relief of eye irritation due to environmental factors (e.g., wind, dry air), and post-surgical eye lubrication. PEG is sometimes used as a lubricant during eye examinations.
- Laxative (PEG 3350): Occasional constipation, bowel preparation before colonoscopy or other procedures.
Dosage Adjustments
No specific dosage adjustments are typically necessary for ophthalmic PEG/PG except as directed by a physician. For oral PEG 3350, monitor renal function and adjust dosage as needed in patients with renal impairment. Reduce dosage or frequency if loose stools or diarrhea develops.
Side Effects
Common Side Effects
- Ophthalmic: Blurred vision (temporary), mild burning or stinging, eye irritation, itching.
- Laxative (PEG 3350): Abdominal bloating, cramping, gas, nausea, diarrhea.
Rare but Serious Side Effects
- Ophthalmic: Severe allergic reactions (rare).
- Laxative (PEG 3350): Severe allergic reactions (rare), severe or persistent diarrhea, rectal bleeding, stomach/abdominal pain.
Long-Term Effects
- Ophthalmic: No significant long-term effects are typically associated with proper use. Overuse can wash away natural tears and worsen symptoms.
- Laxative (PEG 3350): Electrolyte imbalances can occur with prolonged or excessive use.
Adverse Drug Reactions (ADR)
- Ophthalmic: Eye pain, changes in vision, worsening or persistent redness or irritation.
- Laxative (PEG 3350): Severe abdominal pain, bloody stools, dehydration.
Contraindications
- Ophthalmic: Hypersensitivity to any component of the formulation.
- Laxative (PEG 3350): Gastrointestinal obstruction, bowel perforation, toxic colitis or megacolon, gastric retention, ileus, known hypersensitivity to PEG.
Drug Interactions
- Ophthalmic: Not typically known to interact significantly with other medications.
- Laxative (PEG 3350): May interact with other medications that affect bowel function, such as certain antidepressants, antiepileptics, and diuretics. Consult a healthcare professional to identify specific interactions.
Pregnancy and Breastfeeding
- Ophthalmic: Generally considered safe for use during pregnancy and breastfeeding.
- Laxative (PEG 3350): Consult a healthcare professional before use during pregnancy or breastfeeding. Limited systemic absorption suggests minimal risk to the fetus or infant, but individual factors should be considered.
Drug Profile Summary
- Mechanism of Action: Ophthalmic: Lubricates and moisturizes the eye surface. Laxative (PEG 3350): Osmotic laxative that increases stool water content.
- Side Effects: Ophthalmic: Temporary blurred vision, stinging, irritation. Laxative: Bloating, gas, cramping, nausea, diarrhea.
- Contraindications: Ophthalmic: Hypersensitivity. Laxative: Bowel obstruction, perforation, gastric retention.
- Drug Interactions: Ophthalmic: Minimal. Laxative: Consult a healthcare professional.
- Pregnancy & Breastfeeding: Ophthalmic: Generally safe. Laxative: Consult a healthcare professional.
- Dosage: Ophthalmic: 1-2 drops as needed. Laxative: 17 grams daily.
- Monitoring Parameters: Laxative (PEG 3350): Electrolytes with prolonged use.
Popular Combinations
PEG/PG ophthalmic solutions are often combined with other ingredients like hypromellose or carboxymethylcellulose to enhance viscosity and lubrication.
Precautions
- General Precautions: Discontinue use and consult a physician if symptoms worsen or persist.
- Specific Populations: No specific precautions are typically necessary other than those outlined in the “Dosage” section.
- Lifestyle Considerations: No specific lifestyle restrictions are typically associated with PEG/PG ophthalmic solutions or oral PEG 3350.
FAQs
Q1: What is the recommended dosage for Polyethylene Glycol + Propylene Glycol eye drops?
A: Instill 1 or 2 drops in the affected eye(s) as needed, typically up to four times per day.
Q2: What is the recommended dosage for Polyethylene Glycol 3350 for constipation?
A: 17 grams (one heaping tablespoon or one packet) dissolved in 4-8 ounces of liquid once daily.
A: Some brands may be compatible with contact lenses, while others advise removing contacts before instillation. Consult the product instructions or a healthcare professional.
Q4: What should I do if I accidentally ingest PEG/PG eye drops?
A: Small amounts are unlikely to cause harm. If a large quantity is ingested, contact a poison control center.
Q5: Can PEG 3350 be used long-term for chronic constipation?
A: It can be used long-term under the guidance of a healthcare professional. Monitoring for electrolyte imbalances is recommended.
Q6: Are there any dietary restrictions while taking PEG 3350?
A: No specific dietary restrictions are necessary, but it is important to drink plenty of fluids.
Q7: Can pregnant or breastfeeding women use PEG/PG eye drops?**
A: They are generally considered safe, but it is always best to consult a healthcare professional before using any medication during pregnancy or breastfeeding.
Q8: What should I do if I experience side effects from PEG/PG eye drops or PEG 3350?**
A: Discontinue use and consult with a healthcare professional if side effects are bothersome or persistent.
Q9: Can PEG 3350 be used in children?
A: Consult a pediatrician for appropriate dosing in children. Do not administer without consulting a pediatrician.
