Over-the-counter laxative polyethylene glycol 3350: an evidence-based appraisal

Curr Med Res Opin. 2011 Jul;27(7):1439-52. doi: 10.1185/03007995.2011.580339. Epub 2011 May 23.


Objective: To explore the clinical dimensions of chronic constipation and the role played in its treatment by laxatives in general and by polyethylene glycol 3350 (MiraLAX * ) in particular. * MiraLAX is a registered trade name of Schering-Plough HealthCare Products, Inc., Memphis, TN, USA, a subsidiary of Merck & Co., Inc.

Research design and methods: Published reports of clinical trials involving polyethylene glycol 3350, together with published articles examining the epidemiology, demographics, etiology, evaluation, and management of chronic constipation, were identified in a literature search through November 2009 using PubMed. Congress proceedings and guideline databases of leading national and international gastroenterology associations were also explored for relevant recommendations and evaluations.

Main outcome measures: Constipation, often defined differently by patients and physicians, is typically associated with excessive straining, hard stools, infrequent bowel movements, and sensations of incomplete evacuation. Specific criteria are available to aid physicians in making a diagnosis of functional constipation. Initial patient management typically involves dietary and lifestyle changes, although this approach is supported by limited clinical evidence and is often a source of considerable patient frustration. A laxative is needed when these changes do not sufficiently relieve constipation. Multiple agents from several different laxative classes are available, differing in mechanism of action, safety and efficacy profile, and clinical evidence supporting their use.

Results: Twenty-one studies involving a total of 1949 patients were included in the overall review of polyethylene glycol 3350. Fifteen studies used randomized designs, eight were comparative trials, seven were conducted in pediatric populations, and three had elderly components.

Limitations: Limitations of this review included lack of comparability among the various patient populations described; focus on a single agent; potential publication bias; non-systematic review.

Conclusions: Polyethylene glycol 3350, an osmotic laxative available over the counter, has been shown to be safe and effective in treating chronic constipation in children and adults, including the elderly, across multiple clinical trials, with a safety profile comparable to that of placebo. Polyethylene glycol 3350 received a grade A recommendation for improving stool frequency and consistency from the American College of Gastroenterology Task Force on Chronic Constipation.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Adult
  • Algorithms
  • Child
  • Constipation / drug therapy*
  • Evidence-Based Practice / statistics & numerical data
  • Humans
  • Laxatives / adverse effects*
  • Laxatives / therapeutic use*
  • Nonprescription Drugs / adverse effects
  • Nonprescription Drugs / therapeutic use
  • Polyethylene Glycols / adverse effects*
  • Polyethylene Glycols / therapeutic use*
  • Randomized Controlled Trials as Topic


  • Laxatives
  • Nonprescription Drugs
  • Polyethylene Glycols