A low-volume polyethylene glycol plus ascorbate solution for bowel cleansing prior to colonoscopy: the NORMO randomised clinical trial

Background: Patient acceptability of the preparation is a key factor in the success of colonoscopy, yet standard polyethylene glycol solutions are poorly tolerated owing to their high volume (4L) and low palatability. This study compared the efficacy, safety and acceptability of a 2L polyethylene glycol+ascorbate solution with a standard 4-L polyethylene glycol solution.

Methods: Adults referred for colonoscopy were randomised to 2-L polyethylene glycol+ascorbate (n=202) or 4-L polyethylene glycol solution (n=198). Colon cleansing success was assessed using the Harefield Cleansing Scale(©) and the Aronchick scale. Safety and acceptability were also assessed.

Results: Successful cleansing was achieved in 94.1% and 90.9% of subjects with the 2-L and 4-L solutions respectively using the Harefield Cleansing Scale(©) and 94.6% and 90.0% using the Aronchick scale (non significant). Despite better acceptability and tolerability, no superiority over the standard 4-L preparation was demonstrated. Fewer treatment-related adverse events were reported with the 2-L solution (80.2% versus 89.9%, p=0.011). More subjects were willing to take the 2L PEG+ascorbate solution again (87% versus 51%, p<0.001), found it easier to drink (80% versus 70%, p=0.025), with a better taste (p=0.01).

Conclusions: Two-litre polyethylene glycol+ascorbate solution, with a similar high degree of cleansing and superior acceptability and tolerability, presents an alternative to 4-L polyethylene glycol when compliance is an issue.