From the Guidelines
Colonoscopy preparation should involve a split-dose regimen with a bowel-cleansing solution, such as GoLYTELY, MoviPrep, SUPREP, or Plenvu, and a clear liquid diet the day before the procedure, with the second dose of the split preparation beginning 4-6 hours before the time of colonoscopy, as recommended by the US Multi-Society Task Force on Colorectal Cancer 1.
Key Recommendations
- Limit dietary modifications to the day before colonoscopy for ambulatory patients at low risk for inadequate bowel preparation 1
- Use low-residue and low-fiber foods or full liquids for the early and midday meals on the day before colonoscopy 1
- Avoid using hyperosmotic regimens in individuals at risk for volume overload or electrolyte disturbances 1
- Select a bowel preparation regimen that considers the individual’s medical history, medications, and prior colonoscopy results 1
Bowel Preparation Regimens
- Split-dose administration of bowel preparation purgatives is recommended for all patients 1
- Same-day regimen is an acceptable alternative to split dosing for individuals undergoing an afternoon colonoscopy 1
- The second dose of split preparation should begin 4-6 hours before the time of colonoscopy and be completed at least 2 hours before the procedure 1
Additional Considerations
- Patient education and navigation are crucial for improving bowel preparation quality 1
- Oral simethicone may be used as an adjunct to bowel preparation 1
- Nonsimethicone adjuncts should not be used routinely for bowel preparation 1
- Bowel preparation quality should be assessed after all washing and suctioning have been completed 1
From the FDA Drug Label
USE • relieves occasional constipation (irregularity) • generally produces a bowel movement in 1 to 3 days The FDA drug label does not answer the question.
From the Research
Colonoscopy Preparation Methods
- There are two main methods for colonoscopy preparation: oral sodium phosphate and polyethylene glycol solution.
- Studies have compared the efficacy, safety, and acceptability of these two methods.
Efficacy of Colonoscopy Preparation Methods
- A study published in 2002 found that oral sodium phosphate showed a safety profile similar to that of polyethylene glycol, and patients tolerated it better 2.
- Another study published in 1996 found that patients found the sodium phosphate preparation slightly more tolerable than PEG, but side effects were slightly more common with sodium phosphate 3.
- A multicenter trial published in 2008 found that there were no significant differences in tolerability, acceptance, and preparation quality between sodium phosphate, sodium phosphate with sennosides, and polyethylene glycol-based lavage with sennosides 4.
Specific Patient Populations
- A systematic review and meta-analysis published in 2021 found that sodium phosphate was superior to polyethylene glycol in constipated patients undergoing colonoscopy, with a higher chance of successful bowel preparation 5.
- An updated meta-analysis published in 2016 found that sodium phosphate was a better agent than polyethylene glycol for colonoscopy bowel cleansing, with advantages of higher efficacy, better tolerability, and acceptability, as well as comparable safety 6.
Comparison of Side Effects
- Studies have found that sodium phosphate can cause hyperphosphataemia and lower serum potassium levels, but these effects are generally not clinically significant 3, 4.
- Polyethylene glycol-based preparations can cause nausea, vomiting, and abdominal pain, but these side effects are less common with sodium phosphate 6.