Is it appropriate to give Surelax (polyethylene glycol) for constipation?

Is Surelax (Polyethylene Glycol) Appropriate for Constipation?

Yes, polyethylene glycol (PEG) is highly appropriate and recommended as a first-line treatment for constipation, with strong evidence supporting its efficacy, safety, and tolerability across multiple patient populations. 1

Evidence-Based Recommendation

The American Gastroenterological Association and American College of Gastroenterology jointly recommend PEG as a primary treatment option for chronic idiopathic constipation, with an initial dose of 17 grams daily. 1 This recommendation is based on moderate-quality evidence and represents a strong recommendation from the most recent (2023) clinical practice guidelines. 1

Dosing and Administration

• Start with 17 grams daily, which can be titrated based on symptom response and side effects 1
• No clear maximum dose exists, allowing for flexible dose adjustment 1
• Response has been shown to be durable over 6 months of continuous use 1
• Monthly cost is only $10-45, making it highly cost-effective 1

Mechanism and Clinical Efficacy

PEG functions as an osmotic laxative that traps water in the intestine without causing net electrolyte shifts. 1 Multiple high-quality studies demonstrate that PEG is more efficacious than placebo for treating functional constipation in both adults and children. 2 Comparative trials show PEG is superior to lactulose with better tolerability. 2

Safety Profile

Common side effects include bloating, abdominal discomfort, and cramping, but these are generally mild and manageable. 1 Unlike magnesium-based osmotic laxatives, PEG does not cause electrolyte disturbances and can be used safely in patients with renal impairment. 1 Studies demonstrate no changes in measured electrolytes, calcium, glucose, BUN, creatinine, or serum osmolality even with higher doses. 3

Special Populations

Opioid-Induced Constipation

For patients on opioids, PEG can be used as part of the initial bowel regimen, though it should typically be combined with a stimulant laxative like senna. 1 The NCCN Palliative Care guidelines recommend adding PEG if constipation persists despite initial stimulant laxative therapy. 1

Irritable Bowel Syndrome with Constipation (IBS-C)

PEG may be effective for treating constipation in IBS-C, though evidence shows it increases bowel movements without necessarily improving abdominal pain. 1 The British Society of Gastroenterology gives this a weak recommendation with very low-quality evidence, noting abdominal pain is a common side effect in this population. 1

Pediatric Use

PEG is effective and safe for chronic constipation and fecal impaction in children, with better acceptance than non-PEG laxatives. 4 Doses of 1.5 g/kg/day for 4 days have been used successfully in pediatric populations. 1

Pregnancy

PEG-ELS is considered a low-risk option (FDA Category C) and has been reported safe in low doses for treating constipation in 225 pregnant patients. 1 However, lactulose is the only osmotic agent specifically studied in pregnancy. 1

Clinical Algorithm for Use

1. Initial therapy: Start PEG 17 grams daily for general constipation 1, 5
2. For opioid-induced constipation: Combine PEG with senna 8.6-17.2 mg daily from the start 1, 5, 6
3. If inadequate response after 1-2 weeks: Increase PEG dose or add a stimulant laxative 5
4. Target outcome: One non-forced bowel movement every 1-2 days 1, 5
5. If failure after 4-6 weeks of optimized therapy: Consider digital rectal examination to assess for defecatory disorders before escalating to prescription agents 5

Important Caveats

• Ensure adequate hydration as with all osmotic laxatives 1
• Contraindicated in bowel obstruction or ileus 7
• For fecal impaction: PEG is as efficacious as enemas and avoids hospital admission 2
• Long-term use is appropriate: Unlike stimulant laxatives where long-term safety is unknown, PEG has demonstrated sustained efficacy over 6 months 1

When to Consider Alternatives

If PEG fails after adequate trial (4-6 weeks at optimized doses), consider prescription agents like linaclotide, plecanatide, or prucalopride, though these cost significantly more ($523+ monthly versus $10-45 for PEG). 1, 5 Before escalating, perform digital rectal examination to rule out defecatory disorders that would benefit from biofeedback therapy rather than additional laxatives. 5