What is the recommended bowel cleanout regimen for an adult using MiraLAX (polyethylene glycol)

Adult MiraLAX Bowel Preparation Instructions

For adults undergoing colonoscopy bowel preparation, mix the entire 238-gram bottle of MiraLAX into 64 ounces of a sports drink (NOT water) and consume in a split-dose regimen for optimal bowel cleansing. 1

Preparation Instructions

PLEASE FOLLOW THESE INSTRUCTIONS. These instructions differ from the MiraLAX bottle label. This WILL cause you to have diarrhea. 2

Mixing the Solution

• Mix the ENTIRE bottle of MiraLAX (238 grams) into 64 ounces of Gatorade or another sports drink 1
• DO NOT MIX IN WATER - MiraLAX is iso-osmotic but not isotonic, requiring electrolyte-containing fluids for safety 1
• Acceptable clear liquids include: Gatorade, other sports drinks, clear juices (apple, white grape, cranberry - NO PULP), lemonade, or Crystal Light 1
• Shake until MiraLAX is completely dissolved 1

Split-Dose Timing (Strongly Recommended)

Split-dose regimens provide superior bowel cleansing compared to single-dose preparations and are the recommended approach. 1

• Evening before procedure: Drink half (32 ounces) of the MiraLAX solution starting around 6:00 PM 1
• Morning of procedure: Drink the remaining half (32 ounces) starting 4-6 hours before your colonoscopy time 1
• Complete the last dose at least 2 hours before your procedure time 1
• Drink one 8-ounce glass every 30-60 minutes until each portion is finished 1

If You Cannot Do Split-Dosing

For afternoon colonoscopies only, same-day preparation is acceptable: 1

• Start the entire 64-ounce solution at noon or as early as possible 1
• Do not start later than 6:00 PM or you will not get adequate sleep 1
• This will take approximately 4-8 hours to complete 1

Managing Side Effects

• If you become nauseated or feel full, stop drinking for at least 30 minutes 1
• Resume using smaller amounts (4-6 ounces) every 45-60 minutes 1
• It is necessary to drink all of the solution to ensure adequate colon cleansing 1

Expected Results

• Your stools should become liquid and clear enough to see through 1
• The color may be yellow, green, or blue depending on what liquid you mixed with the MiraLAX 1
• You will experience loose, watery, more frequent stools 2

Clear Liquid Diet Requirements

You must follow a clear liquid diet ONLY for the entire day of bowel preparation. 1

Allowed clear liquids include: 1

• Jell-O (no red or purple)
• Popsicles
• Broth
• Gatorade or PowerAde
• Clear fruit juices (apple, white grape, cranberry)
• Kool-Aid (any flavor)
• Crystal Light
• Water

Continue drinking clear liquids even after finishing the MiraLAX solution to maintain hydration and continue flushing your colon. 1

Important Safety Considerations

This Regimen is NOT FDA-Approved

• While widely used in community practice, MiraLAX for colonoscopy preparation is an off-label use and not FDA-approved for this indication 1
• FDA-approved alternatives include GoLYTELY, MoviPrep, Suprep, and other commercial preparations 1

Contraindications and Precautions

Do not use this preparation if you have: 1

• Bowel obstruction or ileus
• Severe kidney disease (creatinine clearance <30 mL/min)
• Congestive heart failure
• Severe electrolyte disturbances
• Allergy to polyethylene glycol

Efficacy Considerations

The evidence on MiraLAX effectiveness is mixed: 3, 4, 5, 6

• Some studies show MiraLAX/Gatorade is less effective than 4L GoLYTELY for bowel cleansing 3, 6
• Other studies demonstrate comparable or superior effectiveness, particularly with split-dosing 5, 4
• Split-dosing significantly improves cleansing quality regardless of preparation type 1, 5
• Patient tolerability and willingness to repeat is consistently higher with MiraLAX/Gatorade compared to high-volume preparations 4, 5

When to Consider FDA-Approved Alternatives

Consider using FDA-approved preparations instead if you have: 1

• History of inadequate bowel preparation
• Chronic constipation or opioid use
• Diabetes mellitus
• Prior colon surgery
• Cirrhosis

For these higher-risk patients, FDA-approved low-volume preparations (Suprep, MoviPrep, Prepopik) or high-volume split-dose PEG-ELS may provide more reliable cleansing. 1