Polyethylene Glycol (PEG) for Constipation: Safety and Efficacy
Polyethylene glycol (PEG) is a safe and effective treatment for constipation and is strongly recommended as a first-line osmotic laxative. 1
Safety Profile
- PEG has an excellent safety profile with minimal systemic absorption, making it suitable for most patients 1
- PEG works as an osmotic laxative that draws water into the intestine to soften stool and increase bowel movements 1
- Unlike other laxatives, PEG causes virtually no net gain or loss of sodium and potassium, making it safer for long-term use 1
- The only absolute contraindication is allergy to polyethylene glycol 2
- Common side effects are generally mild and include bloating, abdominal discomfort, and cramping 1
Efficacy
- PEG is strongly endorsed in systematic reviews of chronic constipation 1
- The American Gastroenterological Association strongly recommends PEG over management without PEG for chronic idiopathic constipation (strong recommendation, moderate certainty of evidence) 1
- Response to PEG has been shown to be durable over 6 months with no evidence of tachyphylaxis (diminished response over time) 3
- Long-term studies have demonstrated safety and efficacy for up to 12 months of continuous use 3
Dosing Considerations
- Standard initial dose is 17g daily, which can be titrated based on symptom response 1
- There is no clear maximum dose, allowing for flexibility in treatment 1
- For acute constipation relief within 24 hours, higher doses (e.g., 68g) may be used safely for short-term treatment 4
- PEG is relatively inexpensive ($10-$45 monthly) compared to prescription constipation medications 1
Special Populations
- PEG is considered safe in elderly patients with no significant changes in electrolytes even with prolonged use 3
- PEG has been shown to be safe and effective in children, including infants under 18 months of age 5, 6
- PEG is preferred over lactulose for chronic constipation in both adults and children, showing better outcomes in stool frequency, stool form, and relief of abdominal pain 7
Clinical Advantages Over Other Laxatives
- PEG is more effective than lactulose, which has a latency of 2-3 days before onset of effect and commonly causes nausea and abdominal discomfort 1, 7
- Unlike magnesium salts, PEG doesn't pose a risk of hypermagnesemia, even with prolonged use 1
- PEG is preferred over bulk laxatives in opioid-induced constipation 1
- PEG is more effective and has fewer side effects than liquid paraffin, which can cause lipoid pneumonia, anal seepage, and skin excoriation 1
Implementation in Practice
- PEG can be used as first-line therapy or after a trial of fiber supplementation for mild constipation 1
- Ensure adequate hydration when using PEG, as with all osmotic laxatives 1
- For chronic constipation, daily maintenance therapy may be required rather than as-needed dosing 3
- If PEG alone is insufficient, combination therapy with stimulant laxatives may be considered for refractory cases 1