What are the risks of long-term use of osmotic laxatives like polyethylene glycol (PEG)?

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Last updated: June 30, 2025View editorial policy

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From the Guidelines

Long-term use of osmotic laxatives like polyethylene glycol (PEG) is not recommended due to potential risks, including electrolyte imbalances, dependency, dehydration, and abdominal discomfort. The main concerns with long-term use of osmotic laxatives include:

  • Electrolyte imbalances, particularly decreased levels of sodium and potassium, which can occur with prolonged use 1
  • Dependency, where the bowel becomes less effective at functioning normally without the medication 1
  • Dehydration, as these medications draw water into the intestines 1
  • Abdominal discomfort, bloating, cramping, or nausea with ongoing use 1
  • Potential nutrient malabsorption with long-term use, though PEG is less likely to cause this than stimulant laxatives 1
  • Tolerance can develop over time, requiring increased doses to achieve the same effect 1 For these reasons, it's generally recommended to use PEG and other osmotic laxatives at the lowest effective dose and for the shortest duration necessary 1. Anyone requiring laxatives for more than two weeks should consult their healthcare provider to investigate underlying causes of constipation and explore lifestyle modifications like increased fiber intake, adequate hydration, and regular physical activity as more sustainable approaches to bowel regularity 1. Some key points to consider when using osmotic laxatives include:
  • Starting with a low dose and gradually increasing as needed 1
  • Monitoring for signs of electrolyte imbalance, such as muscle weakness or heart arrhythmias 1
  • Staying hydrated to minimize the risk of dehydration 1
  • Being aware of potential interactions with other medications, such as diuretics or blood thinners 1
  • Considering alternative treatments, such as fiber supplements or stimulant laxatives, if osmotic laxatives are not effective or are causing adverse effects 1

From the FDA Drug Label

STOP USE AND ASK A DOCTOR IF ... you need to use a laxative for longer than 1 week The long-term use of osmotic laxatives like polyethylene glycol (PEG) is not recommended because it may lead to dependence and other adverse effects.

  • Key risks include:
    • Dependence on laxatives
    • Diarrhea
    • Rectal bleeding
    • Worsening of nausea, bloating, cramping, or abdominal pain 2

From the Research

Risks of Long-Term Use of Osmotic Laxatives

The long-term use of osmotic laxatives like polyethylene glycol (PEG) can have several risks, including:

  • Metabolic disturbances, particularly in the presence of renal impairment 3
  • Dependence on the laxative, leading to decreased bowel function and requiring increasingly higher doses to achieve the same effect
  • Potential for electrolyte imbalances, especially with long-term use of laxatives containing poorly absorbable ions such as magnesium or phosphate 3

Safety and Efficacy of Polyethylene Glycol (PEG)

PEG is generally considered safe and effective for the treatment of chronic constipation, with studies showing its superiority to lactulose and other laxatives in terms of increasing stool frequency and reducing symptoms 4, 5, 6

  • A study comparing PEG to lactulose found that PEG was more effective in increasing stool frequency and reducing straining at stool, with similar clinical tolerance and fewer reports of flatus 4
  • Another study found that PEG was safe and effective for the treatment of childhood constipation, with no serious adverse events reported 7
  • A Cochrane review of 18 studies found that PEG preparations may be superior to placebo, lactulose, and milk of magnesia for childhood constipation, with a low risk of adverse events 6

Potential Adverse Effects

While PEG is generally well-tolerated, potential adverse effects include:

  • Flatulence
  • Abdominal pain
  • Nausea
  • Diarrhea
  • Headache
  • Pruritis ani 6
  • Allergic reactions, although rare 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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