From the Research
For patients with gastric bypass who need to prepare for a colonoscopy, a modified MiraLAX (polyethylene glycol 3350) bowel preparation is recommended, using a split-dose regimen with 175g of MiraLAX dissolved in 64 ounces of clear liquid the evening before the procedure, and another 175g in 64 ounces of clear liquid 4-6 hours before the colonoscopy. This approach is supported by recent studies, including one published in 2021 1, which found that a split-dose regimen with bisacodyl increases the quality of bowel preparation for colonoscopy. The split-dose approach helps ensure complete bowel cleansing while reducing the risk of dehydration or electrolyte imbalances, which is particularly important for patients with gastric bypass due to their altered gastrointestinal anatomy.
Key considerations for patients with gastric bypass include:
- Following a clear liquid diet for 24-48 hours before the procedure
- Avoiding red or purple liquids
- Staying well-hydrated throughout the preparation process
- Maintaining adequate hydration by drinking additional clear fluids between the preparation doses
- Contacting their healthcare provider immediately if they experience severe nausea, vomiting, or abdominal pain during preparation
The use of a split-dose regimen is also supported by other studies, including one published in 2018 2, which emphasizes the importance of adequate bowel cleansing for visualization of the colon and successful detection of colon polyps. Another study published in 2016 3 found that gastric residual volume is similar after split-dose and evening-before bowel preparation, suggesting that the risk of aspiration is identical after either preparation technique. Overall, the split-dose regimen with MiraLAX is a safe and effective approach for patients with gastric bypass who need to prepare for a colonoscopy.