How to Give Polyethylene Glycol (PEG)
For chronic constipation in adults, administer PEG 3350 at 17 g (one heaping tablespoon or one packet) dissolved in 4-8 ounces of any beverage once daily, which can be titrated up to twice daily (34 g total) based on response. 1
Standard Dosing and Administration
Adults with Chronic Constipation
- Initial dose: 17 g once daily mixed in 4-8 ounces of liquid (cold, hot, or room temperature) 1, 2
- Can be increased to 17 g twice daily (34 g total) if inadequate response after 2-3 days 1, 3
- Ensure powder is fully dissolved before drinking—do not consume if clumps remain 2
- Do not combine with starch-based thickeners used for dysphagia 2
- Response is durable over 6 months of continuous use 1, 3
Prophylaxis for Opioid-Induced Constipation
- 17 g with 8 oz water twice daily along with adequate fluid intake 1
- This is preferred over stimulant laxatives alone for prophylaxis in cancer patients on opioids 1
Pediatric Dosing (Children ≥17 years)
- Same as adults: 17 g once daily 2
- For children 16 years and under, consult a physician before use 2
- In clinical practice for younger children, effective maintenance dose averages 0.78-0.84 g/kg/day 4, 5
Dose Titration Algorithm
If constipation persists after 2-3 days: 1, 3
- Increase to 17 g twice daily (morning and evening)
- Continue to monitor for goal of one non-forced bowel movement every 1-2 days 1
If still inadequate after 1 week at maximum dose:
- Rule out fecal impaction (digital rectal exam) and bowel obstruction (physical exam, consider abdominal X-ray) 1
- Consider adding stimulant laxative (bisacodyl 10-15 mg daily) or other osmotic agents 1
- Evaluate for medication-induced constipation (anticholinergics, calcium channel blockers, iron) 6
Severe Constipation/Fecal Impaction
- For disimpaction: Up to 68-85 g per day (divided into multiple doses over 4-6 hours, maximum 1 L/day) for up to 3 days 7, 8
- This higher dosing provides relief within 14-24 hours in severe cases 7, 8
Important Clinical Considerations
Side Effects to Monitor
- Common: Abdominal distension, loose stools, flatulence, nausea 1
- Transient diarrhea may occur—adjust dose downward if this develops 4
- No significant electrolyte disturbances in patients with normal renal function 9, 8
Special Populations Requiring Monitoring
- Patients predisposed to electrolyte imbalances (renal dysfunction, heart failure, elderly on diuretics) should have serum electrolytes monitored 9
- Avoid in patients with known or suspected bowel obstruction 7
Duration of Use
- FDA labeling states "do not use more than 7 days" for over-the-counter use without physician guidance 2
- However, clinical guidelines support long-term use beyond 7 days with physician supervision, with proven durability up to 6 months 1, 3
Key Pitfalls to Avoid
- Do not recommend docusate (stool softener) as it has no proven benefit and is less effective than PEG or stimulant laxatives alone 1
- Do not recommend supplemental fiber (psyllium) for established constipation—it is ineffective and may worsen symptoms 1
- Do not use sodium phosphate enemas more than once daily in patients at risk for renal dysfunction; PEG is safer 1
- Ensure adequate hydration while on PEG therapy, particularly in patients with low baseline fluid intake 1, 3