Efficacy, Tolerance and Safety of Split Dose Bowel Preparation for Colonoscopy: 4L Polyethylene Glycol (PEG) Versus 1L Polyethylene Glycol Plus Sodium Picosulfate-magnesium Citrate (SPMC)


4L split dose PEG is the gold standard for bowel preparation, however it comes with poor tolerability and poor compliance. Combination of PEG with different agent is useful in reducing total volume, improving compliance and tolerance of patient. The objective of this study is to demonstrate that combination bowel preparation, PEG plus SPMC solution, has similar efficacy and safety profile whereas with a better tolerance when compared to large volume PEG.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Double (Investigator, Outcomes Assessor)
  • Study Primary Completion Date: March 2022

Detailed Description

This is a prospective, randomized, single-center, single-blinded, non-inferiority trial. Participants with out patient colonoscopy arranged will be included and randomized in a 1:1 ratio to receive either a split dose of 4L PEG + Electrolyte (Klean-prep® ) or 1L Klean-prep® plus 2 sachets SPMC (Picoprep®). Trained endoscopists will be using the Boston Bowel Preparation Scale (BBPS) to assess the quality of bowel preparation. Patient would also rate the tolerance, compliance and adverse effect by filling the questionnaire before the colonoscopy.


  • Drug: 4L Klean Prep®
    • Patients allocated to the control group shall mix two sachets of PEG in 2L water. At 6pm the evening before examination, they shall consume 250ml solution every 15mins, and finish in 2hours. At 7am the day of examination, drink another 2L Klean-prep in 2 hours.
  • Drug: 1L Klean prep® and 2 sachets Picoprep®
    • Patients allocated to the study group shall mix each sachet of Picoprep® in 150ml warm water. The patient shall take the 1st dose at 4pm the day before procedure followed by at least five 250ml drinks of clear fluid before the next dose. The 2nd dose shall be taken approximately 6hrs later and followed by at least three 250ml drinks of clear fluid before bed. On 7am the day of procedure, they shall take 1L PEG in 1 hour.

Arms, Groups and Cohorts

  • Active Comparator: 4L Klean Prep®
    • Drug: 59g polyethylene glycol, 5.685g Na sulphate, 1.685g Na bicarbonate, 1.465g NaCl, 0.7425g KCl and aspartame 0.0494g
  • Experimental: 1L Klean prep® and 2 sachets Picoprep®
    • Drug: 59g polyethylene glycol, 5.685g Na sulphate, 1.685g Na bicarbonate, 1.465g NaCl, 0.7425g KCl, aspartame 0.0494g, sodium picosulfate 0.01g, magnesium oxide 3.5g, citric acid 12.0g

Clinical Trial Outcome Measures

Primary Measures

  • Boston Bowel Preparation Score (BBPS)
    • Time Frame: Up to 24 weeks
    • Adequate bowel preparation is defined as a total BPPS score >/= 6 in which all three segments had score >/=2

Secondary Measures

  • Patient tolerability to bowel preparation using Likert scale
    • Time Frame: Up to 24 weeks
    • Patient are requested to fill in questionnaire on the day of colonoscopy. Candidate are asked to rate the frequency of complications between ‘none’, ‘mild’, ‘moderate’ and ‘severe’. ‘None’ being the best outcome and ‘severe’ being the worst outcome.
  • Patient compliance towards bowel preparation
    • Time Frame: Till the day of procedure
    • Proportion of patient able to complete the whole bowel preparation as instructed by protocol
  • Proportion of patient requiring repeat colonoscopy
    • Time Frame: Up to 24 weeks
    • Proportion of incomplete colonoscopy due to inadequate bowel preparation Patient will be attended by physicians and blood taking will be arranged
  • Incidence of treatment related adverse events
    • Time Frame: Up to 24 weeks
    • Patient will be monitored after colonoscopy for any complications

Participating in This Clinical Trial

Inclusion Criteria

1. Patient who mentally capable to consent for participating the trial 2. 18 – 65 years old 3. Scheduled for 1st colonoscopy 4. Elective outpatient colonoscopy Exclusion Criteria:

1. Prior colorectal or abdominal-pelvic surgery 2. Inflammatory bowel disease 3. Active bowel condition eg intestinal obstruction 4. Gastrointestinal disorders eg active ulcer, gastric outlet obstruction, gastroparesis and hypomotility syndrome 5. Recent myocardial infarction, congestive heart failure, uncontrolled hypertension 6. Renal dysfunction, hepatic disease 7. Patient on long term tranquilizer, anti-spasmodic, prokinetic, laxative or antidiarrhoeal agents 8. Hypersensitivity to PEG or SPMC solution 9. Pregnant or breastfeeding women 10. Inability to give informed consent

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Queen Elizabeth Hospital, Hong Kong
  • Provider of Information About this Clinical Study
    • Principal Investigator: Tso Yau Kan, Resident – Queen Elizabeth Hospital, Hong Kong
  • Overall Official(s)
    • Yau Kan Tso, Principal Investigator, Queen Elizabeth Hospital, Hospital Authority
  • Overall Contact(s)
    • Yau Kan Tso, 00852 35067479, tyk895@ha.org.hk

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