Is Glycoprep-C (bisacodyl) 70 grams in 1 L a reasonable bowel preparation?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: October 3, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Glycoprep-C 70 grams in 1 L as a Bowel Preparation

Yes, Glycoprep-C 70 grams in 1 L is a reasonable bowel preparation for colonoscopy, as ultra-low volume (1L) preparations offer adequate bowel cleansing efficacy while improving patient tolerability compared to traditional high-volume preparations. 1, 2

Efficacy of Ultra-Low Volume Preparations

  • Ultra-low volume (1L) preparations like Glycoprep-C can achieve adequate bowel cleansing rates comparable to higher volume preparations, with studies showing efficacy rates of 82.9% for 1L PEG with ascorbate preparations 3
  • The US Multi-Society Task Force on Colorectal Cancer guidelines indicate that 1L PEG + ascorbate preparations are associated with reasonable rates of adequate bowel preparation and are noninferior to 2L PEG-ELS preparations 1
  • Some ultra-low volume preparations have demonstrated greater proximal colon polyp detection rates compared to larger volume preparations 1

Patient Tolerability Advantages

  • Low-volume preparations (including 1L formulations) show significantly better tolerability (85.8%) compared to high-volume 4L preparations (48.5%) 1
  • Patient willingness to repeat the preparation is substantially higher with low-volume preparations (92.8%) compared to high-volume preparations (67.7%) 1
  • Ultra-low volume preparations reduce symptoms such as abdominal fullness and pain, leading to higher patient satisfaction rates 4

Important Considerations for Use

  • Split-dosing is strongly recommended for optimal bowel cleansing results, with half the preparation taken the evening before and half taken 4-6 hours before the colonoscopy 1, 2
  • For afternoon colonoscopies, same-day dosing of the entire preparation is an acceptable alternative that provides similar efficacy with better sleep quality 1, 2
  • Additional hydration with clear liquids is important when using ultra-low volume preparations to maintain adequate hydration and optimize bowel cleansing 1

Potential Limitations and Cautions

  • Some meta-analyses suggest that not all ultra-low volume preparations consistently meet the 90% quality standard for adequate bowel preparation defined by current guidelines 3
  • Higher rates of vomiting have been observed with some same-day 1L regimens compared to split-dose 2L regimens 1
  • Patients with risk factors for inadequate bowel preparation (e.g., chronic constipation) may require more aggressive preparation protocols 5

Optimizing Results with Ultra-Low Volume Preparations

  • The timing of preparation is critical: the interval between completion of preparation and colonoscopy should not exceed 11.8 hours for optimal results 6
  • For patients with persistent brown effluent despite completing the preparation, consider additional cleansing measures before proceeding with colonoscopy 5
  • Adding adjuncts like bisacodyl may improve the efficacy of ultra-low volume preparations, particularly in patients at risk for inadequate preparation 1

Glycoprep-C 70 grams in 1L represents a reasonable balance between efficacy and tolerability, making it an appropriate choice for many patients undergoing colonoscopy, especially those who have difficulty tolerating larger volume preparations 1, 7.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Alternatives to GoLYTELY for Colonoscopy Preparation

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Efficacy of ultra-low volume (≤1 L) bowel preparation fluids: Systematic review and meta-analysis.

Digestive endoscopy : official journal of the Japan Gastroenterological Endoscopy Society, 2022

Research

Optimal bowel preparation--a practical guide for clinicians.

Nature reviews. Gastroenterology & hepatology, 2014

Research

The optimal bowel preparation intervals before colonoscopy: A randomized study comparing polyethylene glycol and low-volume solutions.

Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver, 2018

Research

1L- vs. 4L-Polyethylene glycol for bowel preparation before colonoscopy among inpatients: A propensity score-matching analysis.

Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver, 2020

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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.