Low-volume Polyethylene Glycol Research Articles

Randomized Trial of Low-Volume PEG Solution Versus Standard PEG + Electrolytes for Bowel Cleansing Before Colonoscopy

Polyethylene glycol (PEG)-based gut lavage solutions are safe and effective, but require consumption of large volumes of fluid. We compared a new 2 L solution of PEG plus ascorbic acid (PEG + Asc) with standard 4 L PEG with electrolytes (PEG + E) for bowel cleansing before colonoscopy to determine efficacy, safety, and patient acceptability. Consenting adult inpatients scheduled to undergo colonoscopy were randomized to receive either 2 L PEG + Asc or 4 L PEG + E. Preparations were taken as split doses the evening before colonoscopy and the following morning. The PEG + Asc group took 1 L at each administration (i.e., total dose of 2 L). The PEG + E group took 2 L at each administration (i.e., total dose of 4 L). Bowel cleansing success was assessed via videotapes by independent, blinded raters. Statistical noninferiority was predefined as a difference of <15% in the lower limit of the 97.5% confidence interval for treatment difference. Patient views on the preparations were elicited. Adverse events were noted. Successful gut cleansing was achieved in 136 of 153 (88.9%) cases of the PEG + Asc group and 147 of 155 (94.8%) cases of the 4 L PEG + E group (mean difference -5.9 [-12.0-infinity]). The difference fell within the predefined limit for noninferiority. Clinical and laboratory parameters showed no difference in safety profile. Patient ratings of acceptability and taste were better for the PEG + Asc group than for the PEG + E group (P < 0.025). The combination of ascorbic acid and PEG-based bowel preparation reduces the volume patients have to drink without compromising efficacy or safety. The low-volume PEG + Asc preparation was more acceptable to patients, and should, therefore, improve effectiveness in routine practice.

Randomised and Controlled Clinical Trial of Polyethylene Glycol with Electrolytes and Ascorbic Acid in Comparison to Sodium Phosphate for Bowel Preparation Before Colon Cancer Screening Colonoscopy

Introduction: The effectiveness of endoscopic screening for colon cancer depends on good bowel preparation to ensure complete (100%) mucosal visualization. The safety and acceptability of the bowel preparation are of key importance for screening colonoscopies. Aims & Methods: To compare the efficacy, safety and acceptability of bowel preparation with low-volume polyethylene glycol plus electrolytes and ascorbic acid (PEG + Asc, MoviPrep) or sodium phosphate (NaP, Fleet Phospho-soda) in adults undergoing elective colonoscopy for colon cancer screening. Consenting participants were randomized to take either PEG+Asc (n = 242) or NaP (n = 114). PEG + Asc was taken the evening before and the morning of the colonoscopy (total 2 litres), NaP was taken in the morning and evening before the procedure. The primary endpoint was the success of bowel cleansing rated from videotapes by a panel of endoscopists unaware of treatment allocations. Successful cleansing was defined as complete visualization (Grade 2-4 on a scale of 0-4) in all segments. Patients' views about the preparations were also elicited. Adverse events were recorded. Results: The rate of successful bowel cleansing (i.e. complete visualization in all segments) according to the expert raters was significantly higher with PEG + Asc (93.4% [95% CI 89.5 to 96.1]) than with NaP (22.8% [15.5 to 31.6%] p < 0.001). The main difference in cleansing success was in the ascending colon. The proportion of unsuccessful cleansing (Grade 0 or 1) for PEG+Asc and NaP respectively in each segment was: rectum 2%, 18%; sigmoid colon 4%, 26%; descending colon 2%, 24%; transverse colon 3%, 28%; ascending colon 3%, 69%. The acceptability ratings for the preparations were similar (mean visual analogue scores (VAS) ranging from 0 = ‘excellent’ to 100 = ‘very bad’ were 24.4 for PEG + Asc and 28.2 for NaP, p = 0.238). Taste ratings for PEG + Asc were significantly better than for NaP (mean VAS 31.2 and 38.1 respectively, p = 0.011). The proportion of patients prepared to receive the same preparation again was significantly higher in the PEG + Asc group (88% vs 78% p < 0.001). Both preparations were well tolerated. No serious, treatment-related adverse events were reported. Conclusion: PEG + Asc provided superior bowel cleansing to NaP and was better tolerated. Excellent 100% mucosal visualization combined with improved patient acceptability and a good safety profile mean that the 2L PEG + Asc preparation is an ideal bowel preparation for colon cancer screening.

Combined Low-Volume Polyethylene Glycol Solution Plus Stimulant Laxatives versus Standard-Volume Polyethylene Glycol Solution: A Prospective, Randomized Study of Colon Cleansing before Colonoscopy

The effectiveness of polyethylene glycol solutions (PEG) for colon cleansing is often limited by the inability of patients to drink adequate portions of the 4 L solution. The aim of the present study was to determine whether a reduced volume of PEG combined with stimulant laxatives would be better tolerated and as or more effective than the standard dose. Patients undergoing outpatient colonoscopy were randomly assigned to receive either low-volume PEG plus sennosides (120 mg oral sennosides syrup followed by 2 L PEG) or the standard volume preparation (4 L PEG). The subjects rated the tolerability of the preparations and their symptoms. Colonoscopists were blind to the colonic cleansing preparation and graded the cleansing efficacy using a validated tool (the Ottawa scale). The low-volume PEG plus sennosides preparation was significantly better tolerated than the standard large volume PEG (P<0.001) but was less efficacious (P=0.03). Thirty-eight per cent of patients in the large volume PEG group were unable to finish the preparation, compared with only 6% in the reduced volume group. There were no adverse events reported. Although the low-volume PEG plus sennosides preparation was better tolerated, it was not as effective as standard large-volume PEG. However, in view of the significant difference in tolerance, further research investigating possible improvements in the reduced-volume regimen seems warranted.