What is the role of Miralax (Polyethylene Glycol) in colonoscopy preparation?

From the Guidelines

MiraLAX (polyethylene glycol 3350) is a recommended bowel preparation for colonoscopy, with a split-dose regimen being the standard preparation strategy, as it has been shown to improve the quality of bowel cleansing and adenoma detection rates 1.

Key Points to Consider

• The typical regimen involves mixing 238-255 grams of MiraLAX with 64 ounces of clear liquid, consumed over a 2-4 hour period, usually with a split-dose approach, where half of the dose is taken the day before and the other half on the day of the colonoscopy 1.
• A clear liquid diet should be followed the entire day before the procedure, avoiding red, purple, or blue liquids that can interfere with visualization during the colonoscopy.
• The solution works by drawing water into the intestines to flush out stool, with frequent bowel movements expected within 1-3 hours of starting the preparation, continuing until the stool is clear, watery, and yellowish.
• MiraLAX is often preferred due to its lower harshness compared to other bowel preparations, causing fewer side effects like nausea or cramping, as noted in studies comparing its efficacy and tolerability to other preparations 1.

Importance of Bowel Preparation Quality

• Complete bowel cleansing is essential for an effective colonoscopy, as any remaining stool can obscure the view of the colon and potentially hide polyps or other abnormalities.
• Endoscopy units should measure bowel preparation quality routinely and aim for adequate bowel preparation in at least 90% of screening and surveillance colonoscopies, with a goal of achieving a BBPS score of 6, as recommended by recent guidelines 1.

Patient Education and Support

• Bowel preparation instructions should be clearly written at a sixth-grade reading level in the patient’s native language, with additional patient education and support provided for units with suboptimal bowel preparation quality, to improve patient understanding and adherence to the preparation regimen 1.

From the FDA Drug Label

USE • relieves occasional constipation (irregularity) • generally produces a bowel movement in 1 to 3 days The FDA drug label does not answer the question.

From the Research

Bowel Preparation for Colonoscopy

• The use of MiraLAX for colonoscopy has been studied in various trials, with one study finding that split-dosed MiraLAX/Gatorade is an effective, safe, and tolerable option for bowel preparation in low-risk patients 2.
• This study compared the efficacy, safety, and tolerability of single-dosed and split-dosed regimens of MiraLAX/Gatorade with Golytely for bowel preparation before colonoscopy, and found that split-dosed MiraLAX/Gatorade resulted in significantly better cleansing than single-dosed MiraLAX/Gatorade 2.
• Another study found that a split-dose bowel preparation regimen, which may include MiraLAX, is recommended for optimizing bowel preparation quality for colonoscopy 3.
• The use of polyethylene glycol (PEG) for bowel preparation has also been studied, with one meta-analysis finding that split-dose PEG significantly improved the number of satisfactory bowel preparations and increased patient compliance compared to full-dose PEG 4.
• Other studies have compared the efficacy and patient tolerance of different bowel preparations, including oral sodium phosphate solution and polyethylene glycol with bisacodyl, with one study finding that oral sodium phosphate solution is a superior colonoscopy preparation to polyethylene glycol with bisacodyl 5.
• The choice of bowel preparation may depend on various factors, including patient risk factors and medical history, with polyethylene glycol may be safer in patients with a history of significant renal, heart, or liver disease 6.

Efficacy and Safety of MiraLAX

• The study on split-dosed MiraLAX/Gatorade found that there were no clinically significant electrolyte changes from baseline in any subject in any group after bowel prep, and that subjects rated the taste and overall experience of MiraLAX/Gatorade preparation better than Golytely 2.
• The study also found that 96.8% of MiraLAX/Gatorade subjects were willing to repeat the same preparation, compared to 75% for Golytely subjects 2.
• The use of MiraLAX for bowel preparation has been found to be effective and safe in low-risk patients, with a low risk of adverse effects 2.

Recommendations for Bowel Preparation

• The US Multi-Society Task Force on Colorectal Cancer recommends the use of a split-dose bowel preparation regimen, which may include MiraLAX, for optimizing bowel preparation quality for colonoscopy 3.
• The task force also recommends limiting dietary restrictions to the day before a colonoscopy, and relying on either clear liquids or low-fiber/low-residue diets for the early and midday meals 3.
• Routine tracking of the rate of adequate bowel preparations at the level of individual endoscopists and at the level of the endoscopy unit is also recommended, with a target of >90% for both rates 3.