What is the proper use of Golytely (polyethylene glycol) for bowel preparation?

Golytely (Polyethylene Glycol) for Bowel Preparation

Optimal Dosing Strategy

For colonoscopy bowel preparation, use Golytely (4L PEG-ELS) in a split-dose regimen: consume 2L between 7-9 PM the evening before and 2L between 7-9 AM on the day of colonoscopy, completing the second dose 4-6 hours before the procedure and finishing at least 2 hours before colonoscopy start time. 1

Split-Dose vs. Same-Day Administration

Split-dose administration is superior for morning colonoscopies:

• Split-dose 4L PEG provides high-quality bowel cleansing with significantly better preparation quality compared to non-split regimens (OR 4.38; 95% CI 1.88-10.21) 1
• The second portion should begin 4-6 hours before colonoscopy and be completed at least 2 hours before the procedure 1
• Every additional hour between last purgative ingestion and colonoscopy decreases the likelihood of good/excellent preparation by 10% 1

For afternoon colonoscopies only (after 10 AM):

• Same-day dosing is an acceptable alternative with similar bowel preparation quality 1
• Patients report better sleep quality with same-day regimens but may experience more nausea 1
• One study of 120 hospitalized patients showed no significant difference in Ottawa Bowel Preparation scores between split-dose (7.38 ± 3.65) and same-day (7.15 ± 3.58) administration (P=0.75), though patients preferred split-dosing (88.5% vs 70.6% willingness to repeat; P=0.02) 1

Clinical Efficacy and Tolerability

Golytely is effective but has lower tolerability compared to newer preparations:

• In a prospective real-world study of 4,339 colonoscopies, Golytely had significantly lower tolerability than MiraLAX with Gatorade, MoviPrep, Prepopik/Clenpiq, and Suprep (all P<0.05) 2
• Suprep (7.28 ± 1.66; P<0.001), MoviPrep (7.11 ± 1.62; P=0.004), and MiraLAX with Gatorade (7.09 ± 1.64; P<0.001) achieved higher Boston Bowel Preparation Scale scores compared to Golytely (6.67 ± 1.87) 2
• However, 4L PEG-ELS split-dose remains a strong recommendation for high-quality bowel cleansing 1

Special Patient Populations

Golytely is the preferred preparation for patients with significant comorbidities:

• PEG-ELS formulations are iso-osmotic and isotonic, making them the safest choice for patients with renal insufficiency, congestive heart failure, and advanced liver disease 1, 3, 4
• For end-stage renal disease (ESRD) patients, use standard PEG without additives (no ascorbate or sulfate) as a 2L split-dose regimen with careful electrolyte monitoring 3
• PEG-ELS does not cause significant fluid or electrolyte shifts, unlike sodium phosphate preparations which must be avoided in vulnerable patients 4

Volume Reduction Strategies

Lower-volume alternatives may improve tolerability without sacrificing efficacy:

• High-volume (4L) PEG-ELS does not show significantly better bowel cleanliness compared to low-volume (<3L) PEG-ELS (OR 1.03; 95% CI 0.80-1.32) 1
• A modified regimen using 2L Golytely plus 36 mg sennoside achieved excellent or good preparation in 90-97% of subjects with superior patient acceptance 5
• FDA-approved 4L PEG-ELS formulations include Colyte, Gavilyte, Golytely, and Nulytely (sulfate-free) 1, 3

Common Pitfalls to Avoid

Critical timing and patient selection errors:

• Do not use same-day dosing for morning colonoscopies—split-dose generally favors better adenoma detection and preparation tolerability 1
• Avoid hyperosmotic preparations (sodium phosphate, magnesium-containing products) in patients with renal disease, heart failure, or liver disease 3, 4
• Do not use PEG with ascorbate additives in ESRD patients as ascorbate can accumulate and cause metabolic disturbances 3
• Ensure adequate completion time: finishing less than 2 hours before colonoscopy risks aspiration; finishing more than 6 hours before reduces preparation quality 1
• Men, opioid users, tricyclic antidepressant users, and patients with diabetes or cirrhosis have worse cleansing and may require enhanced preparation protocols 2