ColonoscopyLACPEGNCT07787897
Ultra-low Split-dose Oral Lactulose vs High-volume Split-dose Polyethylene Glycol as Bowel Preparation for Outpatient Colonoscopies.
A study testing lactulose and polyethylene glycol (PEG) in people with Colonoscopy, run by National Institute of Medical Sciences and Nutrition, Salvador Zubiran at 1 site in Mexico.
Trial summary
This study compared two different ways to clean the bowel before a colonoscopy: lactulose (a sweet syrup mixed with water) versus high-volume polyethylene glycol (PEG, the usual standard treatment). The goal was to find out which one cleans the bowel better, is easier for patients to take, and has fewer side effects. Read more about this study
- Who is it for?
- Ages 45 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Colonoscopy
- What is being tested?
- lactulose and polyethylene glycol (PEG)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 1 siteMexico
- Study dates
- 29 Jul 2024to 31 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 45 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Patients scheduled for outpatient colonoscopies for colorectal cancer screening Ages 45 to 75 Informed consent form required
Who cannot join
- Pregnancy Patients with colon resections and/or ileostomies Allergy to the medications studied Intolerance to the oral route Hepatic cirrhosis Ascites Chronic kidney disease on peritoneal dialysis or hemodialysis, decompensated heart disease (ischemic heart disease, congestive heart failure, unstable angina) Inflammatory bowel disease Inability to understand the instructions for bowel preparation Suspected intestinal obstruction or perforation Patients with lower gastrointestinal bleeding History of colon cancer History of inadequate bowel preparation History of polyps in previous colonoscopies Bow preparation intake <50%
Trial locations and contacts
1 site in 1 country.
Mexico1 site
National Institute of Medical Sciences and Nutrition Salvador Zubiran
Mexico City, Tlalpan, 14080
About this study
Official title: Ultra-low Split-dose Oral Lactulose vs High-volume Split-dose Polyethylene Glycol as Bowel Preparation for Outpatient Colonoscopies (LACPEG): Randomized, Single-center, Single-blind Clinical Trial.
This study compared two different ways to clean the bowel before a colonoscopy: lactulose (a sweet syrup mixed with water) versus high-volume polyethylene glycol (PEG, the usual standard treatment). The goal was to find out which one cleans the bowel better, is easier for patients to take, and has fewer side effects.
Researchers wanted to answer these main questions:
Read more
Does lactulose clean the bowel as well as PEG according to the Boston Bowel Preparation Scale? Which preparation do patients find more pleasant and are more willing to repeat in the future? Are there differences in side effects such as nausea, vomiting, bloating, or belly pain? Do the two preparations affect how well doctors can see inside the colon, including the chance of finding polyps?
Adults aged 45 to 75 years who were scheduled for a routine outpatient colonoscopy at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán in Mexico City were invited to take part. People with certain serious medical conditions (such as advanced liver disease, kidney failure on dialysis, heart failure, pregnancy, or previous colon surgery) could not join.
Participants were randomly assigned to one of two groups:
Lactulose group: 125 ml of lactulose mixed in 600 ml of water the evening before, and again early the next morning.
PEG group: 2 liters of PEG solution the evening before, and another 2 liters early the next morning.
Both preparations were finished by 6:00 a.m. All participants followed a low-fiber diet the day before the procedure. Doctors performing the colonoscopy did not know which preparation each patient had used.
The study included 200 people (100 in each group).
Read the detailed description
Study Title:
Lactulose oral in split-dose versus high-volume polyethylene glycol in split-dose for bowel preparation in outpatient colonoscopies (LACPEG): a randomized, single-center, single-blind clinical trial.
Background and Rationale Adequate bowel preparation is essential for high-quality colonoscopy. Suboptimal preparation reduces cecal intubation rates, prolongs procedure time, and decreases adenoma detection. International guidelines (ESGE) currently recommend split-dose high-volume polyethylene glycol (PEG) as the gold standard for morning outpatient colonoscopies. However, the large volume required often impairs patient tolerance.
Lactulose, a synthetic disaccharide widely used for constipation, has shown promising results in recent studies as a bowel preparation agent. It requires significantly lower volume, has a more acceptable taste, and has demonstrated good cleansing efficacy with fewer adverse effects compared to PEG in some trials. Nevertheless, high-quality randomized controlled trials comparing split-dose lactulose versus the current gold-standard split-dose 4L PEG are still limited, particularly in Latin American populations. No such studies have been published in Mexico. This trial was designed to address this evidence gap.
Study Design This was a prospective, randomized, single-center, single-blind, parallel-group clinical trial conducted at the Department of Gastrointestinal Endoscopy, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, from July 2024 to December 2025.
Interventions
Eligible patients were randomized 1:1 to one of two split-dose bowel preparation regimens:
Lactulose arm 125 mL lactulose (10 g/15 mL) diluted in 600 mL water, taken between 21:00-22:00 the evening before the procedure.
Second dose: identical regimen (125 mL lactulose in 600 mL water) between 05:00-06:00 on the morning of the procedure.
Polyethylene glycol arm (control) Macrogol 3350 (Nulitely®) - two sachets (109.6 g each) dissolved in 2 L of water, taken between 20:00-22:00 the evening before.
Second dose: identical regimen (two sachets in 2 L water) between 04:00-06:00 on the morning of the procedure.
Both preparations were completed by 06:00. All participants received a low-fiber, low-residue diet the day before colonoscopy. Clear liquids were allowed until 2 hours before the procedure.
Blinding Endoscopists and endoscopy staff were blinded to the preparation assignment. Patients were instructed not to reveal their preparation type.
Procedures Bowel cleansing quality was assessed using the Boston Bowel Preparation Scale (BBPS) in each colonic segment (right, transverse, left). Adequate preparation was defined as total BBPS ≥6. Cecal intubation rate, polyp detection rate, and adenoma detection rate were also recorded. Patient tolerability, taste acceptability (1-10 scale), willingness to repeat the preparation, and adverse effects (nausea, vomiting, abdominal pain, distension) were evaluated using a standardized questionnaire before the procedure.
Statistical Analysis Data were analyzed using SPSS v20.0. Continuous variables are presented as mean ± SD or median (IQR) according to distribution. Categorical variables are presented as frequencies and percentages. Between-group comparisons were performed using Student's t-test, Mann-Whitney U test, or chi-square test as appropriate. A two-sided p-value <0.05 was considered statistically significant.
This study provides direct comparative data on efficacy, tolerability, and safety of split-dose lactulose versus split-dose 4L PEG in a Mexican outpatient population undergoing elective colonoscopy.
- Conditions
- Colonoscopy
- Being tested
- lactulose, polyethylene glycol (PEG)
- Keywords
- colonoscopy, lactulose, low volume bowel preparation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
lactuloseDrug
Lactulose: 125 ml of lactulose (10 g/15 ml) in 600 ml of water will be administered between 9:00 PM and 10:00 PM on the night before the study; subsequently, between 5:00 AM and 6:00 AM on the day of the study, another 125 ml of lactulose (10 g/15 ml) in 600 ml of water will be administered.
polyethylene glycol (PEG)Drug
Polyethylene glycol: 2 sachets of 109.6 grams each, dissolved in 2 liters of water, to be taken between 8:00 PM and 10:00 PM on the night before the study; subsequently, between 4:00 AM and 6:00 AM on the day of the study, another 2 sachets of 109.6 grams each, dissolved in 2 liters of water, are to be administered.
| Study group | Role | What they receive |
|---|---|---|
| Experimental: Oral lactulose in divided doses | Experimental | Participants receive oral lactulose in divided doses as bowel preparation for outpatient colonoscopy. Receives: Drug: lactulose |
| Active Comparator: High-volume polyethylene glycol in split doses | Active comparator | Participants receive high-volume polyethylene glycol in a split-dose regimen as bowel preparation for outpatient colonoscopy. Receives: Drug: polyethylene glycol (PEG) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Quality of bowel preparation assessed using the Boston Bowel Preparation Scale (BBPS)
Total score on the Boston Bowel Preparation Scale (BBPS). The scale evaluates three colon segments (right, transverse, and left), each scored from 0 to 3. The total score ranges from 0 to 9. A higher score indicates better preparation quality. A BBPS score of ≥ 6, with at least 2 points in each segment, is considered adequate preparation.
Measured: During the colonoscopy (day of the procedure)
Polyp detection rate
Percentage of colonoscopies in which at least one polyp was detected.
Measured: During the colonoscopy
Cecal intubation rate
Percentage of colonoscopies in which the cecum was reached (successful cecal intubation).
Measured: During the colonoscopy
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2026
- Study start29 Jul 2024
- Primary completion30 Oct 2024
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ColonoscopyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Care provider
- Enrolment
- 200 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Institute of Medical Sciences and Nutrition, Salvador Zubiran
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Erick Augusto Jasso Baltazar, National Institute of Medical Sciences and Nutrition, Salvador Zubiran
- Investigators
- Ricardo Macias, Doctor, Study chair, National Institute of Medical Sciences and Nutrition, Salvador Zubiran
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07787897
- Sponsor's protocol ID
- 09-CEI-011-20160627
- Other IDs
- 5071
- Acronym
- LACPEG
- Status last verified
- Aug 2026
- First submitted
- 23 Aug 2026
- Last updated
- 26 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Publications
https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0045-1805216
Study at a glance
From the registry record, last updated by the sponsor on 26 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ultra-low Split-dose Oral Lactulose vs High-volume Split-dose Polyethylene Glycol as Bowel Preparation for Outpatient Colonoscopies (LACPEG): Randomized, Single-center, Single-blind Clinical Trial.
- ClinicalTrials.gov ID
- NCT07787897
- Acronym / sponsor ID
- LACPEG / 09-CEI-011-20160627
- Conditions
- Colonoscopy
- Keywords
- colonoscopy, lactulose, low volume bowel preparation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 200 participants (actual)
- Lead sponsor
- National Institute of Medical Sciences and Nutrition, Salvador ZubiranUniversity, hospital or other
- Study start
- 29 Jul 2024 (actual)
- Primary completion
- 30 Oct 2024 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 26 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study compared two different ways to clean the bowel before a colonoscopy: lactulose (a sweet syrup mixed with water) versus high-volume polyethylene glycol (PEG, the usual standard treatment). The goal was to find out which one cleans the bowel better, is easier for patients to take, and has fewer side effects.
Researchers wanted to answer these main questions:
Does lactulose clean the bowel as well as PEG according to the Boston Bowel Preparation Scale? Which preparation do patients find more pleasant and are more willing to repeat in the future? Are there differences in side effects such as nausea, vomiting, bloating, or belly pain? Do the two preparations affect how well doctors can see inside the colon, including the chance of finding polyps?
Adults aged 45 to 75 years who were scheduled for a routine outpatient colonoscopy at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán in Mexico City were invited to take part. People with certain serious medical conditions (such as advanced liver disease, kidney failure on dialysis, heart failure, pregnancy, or previous colon surgery) could not join.
Participants were randomly assigned to one of two groups:
Lactulose group: 125 ml of lactulose mixed in 600 ml of water the evening before, and again early the next morning.
PEG group: 2 liters of PEG solution the evening before, and another 2 liters early the next morning.
Both preparations were finished by 6:00 a.m. All participants followed a low-fiber diet the day before the procedure. Doctors performing the colonoscopy did not know which preparation each patient had used.
The study included 200 people (100 in each group).
Detailed description
Study Title:
Lactulose oral in split-dose versus high-volume polyethylene glycol in split-dose for bowel preparation in outpatient colonoscopies (LACPEG): a randomized, single-center, single-blind clinical trial.
Background and Rationale Adequate bowel preparation is essential for high-quality colonoscopy. Suboptimal preparation reduces cecal intubation rates, prolongs procedure time, and decreases adenoma detection. International guidelines (ESGE) currently recommend split-dose high-volume polyethylene glycol (PEG) as the gold standard for morning outpatient colonoscopies. However, the large volume required often impairs patient tolerance.
Lactulose, a synthetic disaccharide widely used for constipation, has shown promising results in recent studies as a bowel preparation agent. It requires significantly lower volume, has a more acceptable taste, and has demonstrated good cleansing efficacy with fewer adverse effects compared to PEG in some trials. Nevertheless, high-quality randomized controlled trials comparing split-dose lactulose versus the current gold-standard split-dose 4L PEG are still limited, particularly in Latin American populations. No such studies have been published in Mexico. This trial was designed to address this evidence gap.
Study Design This was a prospective, randomized, single-center, single-blind, parallel-group clinical trial conducted at the Department of Gastrointestinal Endoscopy, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, from July 2024 to December 2025.
Interventions
Eligible patients were randomized 1:1 to one of two split-dose bowel preparation regimens:
Lactulose arm 125 mL lactulose (10 g/15 mL) diluted in 600 mL water, taken between 21:00-22:00 the evening before the procedure.
Second dose: identical regimen (125 mL lactulose in 600 mL water) between 05:00-06:00 on the morning of the procedure.
Polyethylene glycol arm (control) Macrogol 3350 (Nulitely®) - two sachets (109.6 g each) dissolved in 2 L of water, taken between 20:00-22:00 the evening before.
Second dose: identical regimen (two sachets in 2 L water) between 04:00-06:00 on the morning of the procedure.
Both preparations were completed by 06:00. All participants received a low-fiber, low-residue diet the day before colonoscopy. Clear liquids were allowed until 2 hours before the procedure.
Blinding Endoscopists and endoscopy staff were blinded to the preparation assignment. Patients were instructed not to reveal their preparation type.
Procedures Bowel cleansing quality was assessed using the Boston Bowel Preparation Scale (BBPS) in each colonic segment (right, transverse, left). Adequate preparation was defined as total BBPS ≥6. Cecal intubation rate, polyp detection rate, and adenoma detection rate were also recorded. Patient tolerability, taste acceptability (1-10 scale), willingness to repeat the preparation, and adverse effects (nausea, vomiting, abdominal pain, distension) were evaluated using a standardized questionnaire before the procedure.
Statistical Analysis Data were analyzed using SPSS v20.0. Continuous variables are presented as mean ± SD or median (IQR) according to distribution. Categorical variables are presented as frequencies and percentages. Between-group comparisons were performed using Student's t-test, Mann-Whitney U test, or chi-square test as appropriate. A two-sided p-value <0.05 was considered statistically significant.
This study provides direct comparative data on efficacy, tolerability, and safety of split-dose lactulose versus split-dose 4L PEG in a Mexican outpatient population undergoing elective colonoscopy.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (care provider)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Experimental: Oral lactulose in divided doses | Experimental | Drug: lactuloseParticipants receive oral lactulose in divided doses as bowel preparation for outpatient colonoscopy. |
| Active Comparator: High-volume polyethylene glycol in split doses | Active comparator | Drug: polyethylene glycol (PEG)Participants receive high-volume polyethylene glycol in a split-dose regimen as bowel preparation for outpatient colonoscopy. |
Who may qualify
- Ages
- 45 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Patients scheduled for outpatient colonoscopies for colorectal cancer screening Ages 45 to 75 Informed consent form required
Key exclusion criteria (1 listed)
- Pregnancy Patients with colon resections and/or ileostomies Allergy to the medications studied Intolerance to the oral route Hepatic cirrhosis Ascites Chronic kidney disease on peritoneal dialysis or hemodialysis, decompensated heart disease (ischemic heart disease, congestive heart failure, unstable angina) Inflammatory bowel disease Inability to understand the instructions for bowel preparation Suspected intestinal obstruction or perforation Patients with lower gastrointestinal bleeding History of colon cancer History of inadequate bowel preparation History of polyps in previous colonoscopies Bow preparation intake <50%
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| lactuloseLactulose: 125 ml of lactulose (10 g/15 ml) in 600 ml of water will be administered between 9:00 PM and 10:00 PM on the night before the study; subsequently, between 5:00 AM and 6:00 AM on the day of the study, another 125 ml of lactulose (10 g/15 ml) in 600 ml of water will be administered. | Drug | Experimental: Oral lactulose in divided doses |
| polyethylene glycol (PEG)Polyethylene glycol: 2 sachets of 109.6 grams each, dissolved in 2 liters of water, to be taken between 8:00 PM and 10:00 PM on the night before the study; subsequently, between 4:00 AM and 6:00 AM on the day of the study, another 2 sachets of 109.6 grams each, dissolved in 2 liters of water, are to be administered. | Drug | Active Comparator: High-volume polyethylene glycol in split doses |
Primary outcome
Quality of bowel preparation assessed using the Boston Bowel Preparation Scale (BBPS)
Time frame: During the colonoscopy (day of the procedure)
Total score on the Boston Bowel Preparation Scale (BBPS). The scale evaluates three colon segments (right, transverse, and left), each scored from 0 to 3. The total score ranges from 0 to 9. A higher score indicates better preparation quality. A BBPS score of ≥ 6, with at least 2 points in each segment, is considered adequate preparation.
Polyp detection rate
Time frame: During the colonoscopy
Percentage of colonoscopies in which at least one polyp was detected.
Cecal intubation rate
Time frame: During the colonoscopy
Percentage of colonoscopies in which the cecum was reached (successful cecal intubation).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Aug 2026.
- Results publicationhttps://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0045-1805216
- Individual participant dataSharing planned: Yes
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ricardo Macias, Doctor study chair
National Institute of Medical Sciences and Nutrition, Salvador Zubiran
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing lactulose and polyethylene glycol (PEG) in people with Colonoscopy, run by National Institute of Medical Sciences and Nutrition, Salvador Zubiran at 1 site in Mexico.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Mexico. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Quality of bowel preparation assessed using the Boston Bowel Preparation Scale (BBPS) (time frame: During the colonoscopy (day of the procedure)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07787897, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Aug 2026.