The Use of Osmotic Laxatives Versus Macrogol for Bowel Preparation in Patients Undergoing Colonoscopy

The key method of colorectal examination is colonoscopy. The result, diagnostic significance and therapeutic safety depend a lot on the quality of bowel preparation. One of the main purposes of colonoscopy is detecting the earliest forms of colorectal cancer and prognostically meaningful small nonpolyposis neoplasms. The good and perfect bowel preparation is essential in this case.

However, the bowel preparation for colonoscopy must fulfill the following criterias:

• Be effective, that means to empty colon of faeces, residual liquid and foamy content fully and safely;
• Harmless, no side effects on the other organs and systems;
• Do not cause discomfort nor change to electrolyte balance, well tolerated;
• Do not affect the severity of bowel disease nor cause macro- and microscopic colon mucose changes;
• Quick response with short preparation period (no more than 24 hours);
• Easy to use, so patient could perform it independently or with the least medical staff participation;
• Do not require special conditions, equipment and staff training (possibility to perform at home);
• Do not distort the endoscopic image (colour, shape, reflexion);
• Do not limit the use of vital dyes or other means of endoscopic diagnosis and treatment;
• Do not damage the endoscopic equipment;
• be cheap . Bowel preparation schemes usually include diet (low-residue) and oral laxative intake. The low-residue diet should last no more than 24 hours before the colonoscopy according to the European Society of Gastrointestinal Endoscopy clinical recommendations.

The time factor is essential for quality of bowel preparation. If the colonoscopy is performed in the first half of day the intake of the part of laxatives (usually a half) on that day (split-mode or separate) provides a better result in comparison to full dose intake on the colonoscopy day or the evening before it.

Bowel preparation might be fully undertaken (in full volume) in the morning of examination day for patients undergoing colonoscopy in the afternoon according to some studies. In the case of laxative intake on the morning of examination day, excellent preparation quality and good patient tolerance was demonstrated in the Varughese S et al. research assessing 4 liters bowel preparation scheme efficiency for patients undergoing colonoscopy in the afternoon in comparison to intake in the evening before colonoscopy.

The patient's somatic status and the urgency should be considered for choosing the bowel preparation mode.

Polyethyleneglycol-based drugs have become more commonly used in clinical practice for colonoscopy bowel preparation since its appearance in 1980.

The drug passes through the intestine without being absorbed and metabolized and increases the bowel liquid volume, as do all osmotic laxatives. Thus, electrolyte balance is not disrupted and effective intestinal lavage occurs. But patient compliance might be influenced significantly due to a large volume intake requirement (4 l) and specific organoleptic feature.

Over the course of several years, European and Canadian experts have accepted the sodium picosulfate+ magnesium citrate-based low-volume bowel preparation method (2l) as alternative option and the FDA has also approved it in July 2012.

This combined intake scheme allows to prepare intestine efficiently for the examination. The sodium picosulfate has a bowel stimulating effect and as osmotic laxative magnesium citrate retains water. But the electrolyte balance changes and dehydration may also influence the patient compliance to laxative.

According to the international clinical recommendations for colonoscopy, 4l polyethylenуglycol-based laxative in split-mode preparation with an time interval no more than 4 hours from the end of preparation until colonoscopy is recommended as a standard method. Low-dose polyethylenуglycol-based laxative intake (2l) combined with ascorbate or sodium thiosulfate+ magnesium citrate can serve as alternative examination preparation method (especially for outpatients). Only polyethylenуglycol-based laxative can be recommended for patients with renal failure as bowel preparation method.

Eziclen - potassium, magnesium and sodium sulphates-based osmotic laxative for colonoscopy preparation registered in Russia doesn't have a strong evidence base and is not included in national recommendations yet due to its recent market entry (2018) But according to the registered multicenter controlled clinical trials assessing the potassium, magnesium and sodium sulfates vs. 2l polyethyleneglycol with electrolytes efficiency for colonoscopy preparation in split-mode (n=356) and one-day preparation (n=364) (primary endpoint - bowel purity degree as "perfect", "good", "bad") as well as non-conceded Eziclen efficiency was identified in comparing to the control group (97,2% vs 96,1% and 84% vs 82,9% respectively). The side effects frequency was also comparable with control group. There was shown a comparable rate of effective bowel preparation (97,2% vs 97,7%) on a background of higher patient compliance (95,7 % comparing to 82,3 %) in a similar study assessing Eziclen efficiency, safety and patient compliancy in comparison with Macrogol 400 with electrolytes.

So the investigators aimed our study to investigate efficiency, safety and compliance of two low-volume laxatives Potassium Sulfate+ Magnesium Sulfate+ Sodium Sulfate-based (Eziclen) vs. relevant volume of Macrogol-3350+ Sodium Sulfate+ Potassium Chloride+ Sodium Chloride+ Ascorbic Acid and Sodium Ascorbate-based (Moviprep) in bowel preparation for colonoscopy.