Polyethylene Glycol (PEG) for Constipation Management
Polyethylene glycol (PEG) is strongly recommended as a first-line treatment for constipation at a standard dose of 17g daily, which effectively increases bowel movement frequency and improves stool consistency with minimal side effects. 1
Mechanism and Efficacy
- PEG is a long-chain polymer of ethylene oxide that acts as an osmotic laxative, drawing water into the intestinal lumen to soften stool and stimulate bowel movements 1
- PEG significantly increases complete spontaneous bowel movements (CSBMs) by approximately 2.90 per week and spontaneous bowel movements (SBMs) by 2.30 per week compared to placebo 1
- Treatment response rates are significantly higher with PEG compared to placebo (312 more responders per 1,000 patients) 1
- PEG typically produces a bowel movement within 1-3 days of administration 2
Dosing Recommendations
- Standard dose: 17g of PEG 3350 once daily mixed in 8 ounces (240mL) of liquid 1, 2
- For chronic idiopathic constipation (CIC), PEG has demonstrated efficacy for up to 6 months of continuous use 1
- For more rapid relief of constipation, a higher dose of 68g has been shown to be effective and safe for producing bowel movements within 24 hours 3
- PEG is available both with and without electrolytes; both formulations are effective, though PEG without electrolytes is more commonly used in the US 1
Clinical Applications
- PEG is FDA-approved for treatment of occasional constipation 1, 2
- PEG is strongly recommended for chronic idiopathic constipation (CIC) based on moderate quality evidence 1
- PEG can be used either after a trial of fiber supplementation or in combination with fiber for enhanced efficacy 1
- For irritable bowel syndrome with constipation (IBS-C), PEG is conditionally recommended to improve bowel movement frequency, though evidence for global symptom improvement is limited 1
- PEG is also effective for constipation caused by medications with constipating side effects 4
Advantages Over Other Laxatives
- PEG has demonstrated similar or greater efficacy compared to other laxatives including tegaserod, prucalopride, and lactulose 1
- In direct comparison studies, PEG showed superior efficacy to lactulose with fewer side effects, particularly less flatulence 5
- PEG is widely available without prescription and is relatively inexpensive 1
Safety Profile
- PEG has a favorable safety profile with minimal systemic absorption 1
- Common side effects include bloating, flatulence, and diarrhea, which are generally mild to moderate 1
- No significant differences in laboratory findings or serious adverse events have been observed between PEG and placebo 4
- PEG does not cause electrolyte imbalances when used at recommended doses 3
- PEG is safe for use in both adults and children 6
Implementation Considerations
- Response to PEG treatment is typically durable over extended periods (up to 6 months in clinical trials) 1
- PEG can be used in advanced cancer patients with constipation, though caution should be exercised in debilitated patients 1
- For patients with mild constipation, a trial of fiber supplementation before or in combination with PEG may be beneficial 1
- Adequate hydration should be maintained during PEG therapy 1