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Polyethylene Glycol

GenericPolyethylene Glycol 3350

Brand namesMiraLAX

Polyethylene Glycol is used to treat constipation. It is available as MiraLAX and is commonly prescribed in the gastrointestinal category.

Reviewed by Zimmer Medical GroupUpdated 8 min read
GastrointestinalLaxativesConstipation

About Polyethylene Glycol

Polyethylene Glycol is an osmotic laxative (polymer) (generic name: Polyethylene Glycol 3350) also known by the brand name MiraLAX. It is primarily used to is prescribed to treat: • Constipation • Various related conditions in the gastrointestinal category • Associated symptoms and complications It is an important medication that helps manage these conditions effectively. Polyethylene Glycol is available in oral powder for solution (17 g packet or scoop), oral powder bulk container (238 g, 510 g, 765 g), and oral solution for bowel preparation (peg with electrolytes — golytely, nulytely, moviprep) form. Healthcare providers commonly prescribe Polyethylene Glycol for conditions including Attention Deficit Hyperactivity Disorder (ADHD), Lupus Anticoagulant, and Vertigo.

Polyethylene Glycol at a Glance

Generic name
Polyethylene Glycol 3350
Brand names
MiraLAX
Drug class
Osmotic Laxative (Polymer)
Pregnancy category
FDA Category Category C — Polyethylene glycol 3350 is minimally absorbed from the gastrointestinal tract, and systemic exposure during pregnancy is negligible. It is widely considered safe during pregnancy and breastfeeding, and is often a first-line option for constipation in pregnancy when dietary measures are insufficient.
Available forms
Oral powder for solution (17 g packet or scoop), Oral powder bulk container (238 g, 510 g, 765 g), Oral solution for bowel preparation (PEG with electrolytes — GoLYTELY, NuLYTELY, MoviPrep)
Therapeutic categories
Gastrointestinal, Laxatives, Constipation
Conditions treated
3 related conditions on this site

What Polyethylene Glycol Is Used For

is prescribed to treat:

• Constipation • Various related conditions in the gastrointestinal category • Associated symptoms and complications

It is an important medication that helps manage these conditions effectively.

Dosage Quick Reference

These are general dosage guidelines for Polyethylene Glycol. Your doctor will determine the appropriate dose for your specific situation.

ConditionStarting DoseMaintenance Dose
Occasional constipation (adults and children ≥ 17 years)17 g (1 capful) dissolved in 4–8 oz of liquid once dailySame; use no longer than 7 days without medical guidance
Chronic constipation (adults, off-label long-term)17 g once dailyAdjust to 8.5–34 g/day to achieve 1 soft bowel movement per day
Pediatric chronic constipation (off-label, ages 6 months–16 years)0.4–0.8 g/kg/day (max 17 g/day)Titrate to effect under pediatric guidance
Bowel preparation for colonoscopy (PEG-electrolyte)4 L PEG-electrolyte solution evening before procedureOr split-dose: 2 L evening before, 2 L morning of

Side Effects

Common side effects may include:

• Nausea or stomach upset • Headache • Dizziness or lightheadedness • Fatigue or tiredness • Mild rash or itching

Serious side effects (seek immediate medical attention):

• Severe allergic reactions (rash, hives, swelling, difficulty breathing) • Unusual bleeding or bruising • Severe stomach pain • Signs of liver problems (yellowing of skin/eyes, dark urine) • Chest pain or irregular heartbeat • Severe dizziness or fainting • Signs of serious adverse effects

See also: Drug Interactions ↓

Drug Interactions

Polyethylene glycol 3350 is minimally absorbed and has very few systemic interactions. The clinically important issues relate to gut transit and absorption of co-administered oral medications.

  • Oral medications taken concurrently: PEG accelerates intestinal transit during bowel preparation regimens, potentially reducing absorption of other oral drugs. Take essential oral medications (including birth control pills, anticonvulsants, and immunosuppressants) at least 1 hour before starting a PEG bowel prep, and consult your prescriber about timing for the day of the procedure.
  • Sodium phosphate bowel preparations: Should not be combined with PEG — additive risks of electrolyte disturbances and acute phosphate nephropathy.
  • Diuretics: When PEG is used for bowel prep, the volume of fluid required can interact with diuretics in patients with heart failure or kidney disease. Hold or adjust diuretics on the day of preparation per your prescriber.
  • Lithium and digoxin: Both have narrow therapeutic windows. Bowel-prep doses of PEG can transiently alter their absorption; recheck levels after the procedure if clinically indicated.
  • Anticoagulants: Although PEG itself does not interact, bowel preparation often coincides with periprocedural anticoagulant management, which requires coordination with the prescribing clinician.

See also: Questions to Ask Your Doctor ↓

Key Considerations

Known drug interactions

Polyethylene Glycol has documented interactions with other medications, supplements, and certain foods. Review the Drug Interactions section below and tell your healthcare provider about every medication you take, including over-the-counter products. Jump to section →

Multiple forms available

Polyethylene Glycol comes in more than one form (Oral powder for solution (17 g packet or scoop), Oral powder bulk container (238 g, 510 g, 765 g), Oral solution for bowel preparation (PEG with electrolytes — GoLYTELY, NuLYTELY, MoviPrep)). The right form for you depends on your condition, ease of use, and your provider's recommendation.

Additional Information

What is ?

Polyethylene Glycol (generic name: Polyethylene Glycol 3350) is a medication primarily used to treat constipation. It is marketed under the brand name(s) MiraLAX and belongs to the Gastrointestinal category of medications.

How Does Polyethylene Glycol Work?

Polyethylene Glycol works through several mechanisms to provide therapeutic benefits:

  • Acts on specific receptors or pathways in the body
  • Modulates biological processes related to the treated condition
  • Provides symptom relief and improves quality of life
  • Helps manage the underlying condition effectively
  • Works best when combined with appropriate lifestyle modifications

The medication is designed to target the specific pathways involved in constipation, making it an effective treatment option.

Common Uses

Primary Indications

Polyethylene Glycol is commonly prescribed for:

  • Constipation: The main indication for this medication
  • Related Conditions: Associated symptoms and complications
  • Prevention: May help prevent progression of certain conditions
  • Symptom Management: Reduces discomfort and improves daily function

Additional Uses

In some cases, Polyethylene Glycol may also be prescribed for:

  • Off-label uses as determined by your healthcare provider
  • Combination therapy with other medications
  • Long-term management of chronic conditions
  • Short-term treatment of acute symptoms

Dosage and Administration

Polyethylene Glycol dosing varies based on the specific condition being treated and individual patient factors.

Typical Dosing:

  • Starting dose is typically determined by your healthcare provider
  • May be adjusted based on response and tolerability
  • Can be taken with or without food (follow specific instructions)
  • Usually taken once or twice daily

Administration Tips:

  • Take at the same time(s) each day for best results
  • Swallow tablets/capsules whole unless instructed otherwise
  • Don't skip doses
  • Complete full course of treatment as prescribed
  • Follow your doctor's specific instructions carefully

Important Safety Information

Who Should Not Take Polyethylene Glycol?

Do not take Polyethylene Glycol if you:

  • Are allergic to Polyethylene Glycol 3350 or any ingredients
  • Have certain medical conditions (discuss with your doctor)
  • Are taking medications that interact with Polyethylene Glycol
  • Have severe liver or kidney disease (without dose adjustment)

Drug Interactions

Inform your doctor about all medications you take, including:

  • Prescription medications
  • Over-the-counter drugs
  • Vitamins and supplements
  • Herbal products

Some medications may interact with Polyethylene Glycol, affecting its efficacy or increasing side effect risk.

Pregnancy and Breastfeeding

Pregnancy:

  • Discuss risks and benefits with your doctor if pregnant or planning pregnancy
  • May require special monitoring or dose adjustments
  • Some medications should be avoided during pregnancy

Breastfeeding:

  • Consult your doctor about safety while breastfeeding
  • May pass into breast milk
  • Benefits and risks should be carefully considered

Monitoring and Follow-Up

While taking Polyethylene Glycol, your doctor may monitor:

  • Effectiveness of treatment (symptom improvement)
  • Side effects or adverse reactions
  • Laboratory values if applicable
  • Blood pressure, heart rate, or other vital signs as appropriate
  • Overall response to therapy

Regular follow-up appointments are important to ensure the medication is working properly and to make any necessary adjustments.

Managing Side Effects

Most side effects are mild and improve with time. Here are strategies for common side effects:

Gastrointestinal Upset

  • Take with food if allowed
  • Stay well hydrated
  • Eat smaller, more frequent meals
  • Report persistent nausea or vomiting

Dizziness

  • Rise slowly from sitting or lying positions
  • Avoid sudden movements
  • Stay hydrated
  • Avoid alcohol
  • Report severe or persistent dizziness

Fatigue

  • Get adequate rest
  • Maintain regular sleep schedule
  • Exercise as tolerated
  • Report excessive tiredness that interferes with daily activities

Lifestyle Considerations

To maximize the benefits of Polyethylene Glycol:

  • Follow a healthy, balanced diet
  • Exercise regularly as recommended by your doctor
  • Maintain a healthy weight
  • Avoid alcohol or limit consumption
  • Don't smoke
  • Manage stress through relaxation techniques
  • Get adequate sleep
  • Stay well hydrated
  • Keep all follow-up appointments
  • Take medication consistently as prescribed

When to Contact Your Doctor

Seek immediate medical attention if you experience:

  • Signs of severe allergic reaction (difficulty breathing, severe rash, swelling)
  • Chest pain or rapid heartbeat
  • Severe dizziness or fainting
  • Unusual bleeding or bruising
  • Signs of liver problems (yellowing of skin/eyes, dark urine, severe fatigue)
  • Severe stomach pain
  • Any symptoms that concern you

Contact your doctor for non-emergency issues:

  • Mild to moderate side effects that persist
  • Questions about your medication
  • Concerns about effectiveness
  • New medications prescribed by another doctor
  • Scheduled surgery or dental procedures
  • Planning pregnancy

Storage

Store Polyethylene Glycol at room temperature (68-77°F or 20-25°C) away from light, heat, and moisture. Keep in original container. Keep out of reach of children and pets. Do not use past expiration date.

Important Reminders

  • Take exactly as prescribed by your doctor
  • Don't stop suddenly without medical advice
  • Keep all follow-up appointments
  • Report any unusual symptoms
  • Don't share medication with others
  • Store safely away from children
  • Check expiration dates
  • Ask your pharmacist if you have questions

Clinical Benefits

When used appropriately, Polyethylene Glycol provides several benefits:

  • Effective management of constipation
  • Improvement in quality of life
  • Reduction in symptoms
  • Prevention of complications
  • Generally well-tolerated when used as directed
  • Backed by clinical research and extensive use

Disclaimer: This information is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified healthcare provider with any questions about a medical condition or medication.

Frequently Asked Questions

For chronic constipation, PEG typically produces a bowel movement within 1 to 3 days of starting. It is not a fast-acting laxative — unlike stimulant laxatives that work within hours, PEG works gradually by drawing water into the colon to soften stool. Daily consistent use produces the best results.
Yes. Although the over-the-counter label limits use to 7 days, multiple long-term studies — including in children — have demonstrated PEG's safety and effectiveness for chronic constipation when used under medical supervision. It does not cause electrolyte abnormalities, dependence, or "lazy bowel" with prolonged use.
PEG is an osmotic laxative — it draws water into the bowel to soften stool and increase volume. Stimulant laxatives directly stimulate intestinal muscle contractions. PEG is gentler, slower-acting, and considered safer for long-term use. Stimulant laxatives are best for short-term or occasional relief.
Yes. PEG dissolves easily in water, juice, coffee, tea, or any non-carbonated beverage. Many patients find the taste neutral when mixed with a flavored drink. The medication remains effective regardless of the liquid used; choose what makes consistent daily use easier.
Colonoscopy bowel prep uses 2 to 4 liters of PEG-electrolyte solution to flush the colon completely so the endoscopist can clearly see the lining and detect polyps or other abnormalities. Adequate cleansing significantly improves polyp detection. Split-dose preparation (half the evening before, half the morning of) is now the standard because it produces better visualization and is easier to tolerate.

Questions to Ask Your Doctor About Polyethylene Glycol

Consider discussing these topics at your next appointment:

  • Could my chronic constipation be caused by another medication or an underlying condition?
  • Is PEG appropriate for me long-term, or should I consider a different approach?
  • What dietary and lifestyle changes can support bowel regularity alongside PEG?
  • When should I seek evaluation for symptoms like rectal bleeding, weight loss, or new abdominal pain?
  • How should I time my other medications around a bowel preparation?
Schedule an Appointment

Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.