What laxatives are suitable for patients who have undergone gastric bypass (Roux-en-Y gastric bypass) surgery?

From the Guidelines

For gastric bypass patients needing laxatives, I recommend starting with gentle options like MiraLAX (polyethylene glycol) at a standard dose of 17g dissolved in 8 ounces of water once daily, as it is generally safe and effective in promoting laxation, as supported by moderate-quality evidence 1. This approach is based on the understanding that laxatives work via various mechanisms to improve bowel movements, and osmotic laxatives like polyethylene glycol (PEG) are particularly beneficial in drawing water into the gut, thereby hydrating the stool, as outlined in the American Gastroenterological Association guideline 1. Key considerations for managing constipation in gastric bypass patients include:

• Starting with gentle laxative options to minimize the risk of adverse effects on the newly altered digestive system
• Avoiding stimulant laxatives like bisacodyl (Dulcolax) and senna in the early post-operative period due to their potential harshness
• Using stool softeners like docusate sodium (Colace) at 100mg once or twice daily as an adjunctive measure
• Introducing fiber supplements cautiously and only after clearance from the surgeon, typically not in the first few months after surgery
• Maintaining adequate hydration by drinking at least 64 ounces of water daily to prevent dehydration, which can worsen constipation
• Consulting the bariatric team if constipation persists despite these measures, given the specialized care required for patients with altered anatomy. The rationale behind these recommendations is grounded in the principle of minimizing morbidity, mortality, and improving quality of life for gastric bypass patients, who are at risk of constipation due to reduced food intake, pain medications, dietary changes, and decreased physical activity during recovery 1.

From the Research

Laxative Options for Gastric Bypass Patients

• Gastric bypass patients may experience constipation due to changes in their digestive system 2
• Psyllium is a laxative that can increase defecation frequency and stool weight in constipated individuals 3, 4
• Psyllium works by forming a gel-like substance that helps to soften and bulk up stool, making it easier to pass 4
• Thiamine deficiency is a common issue in gastric bypass patients and can cause constipation, among other symptoms 2
• Treatment of thiamine deficiency can help to improve constipation symptoms in gastric bypass patients 2

Considerations for Laxative Use in Gastric Bypass Patients

• Gastric bypass patients may have altered drug absorption due to changes in their digestive system 5
• Liquid formulations of laxatives may be beneficial for gastric bypass patients, but the high sugar load of these suspensions should be considered 5
• Extended-release medications may have an unaltered exposure in gastric bypass patients, but more research is needed to confirm this 5
• A risk assessment on a case-by-case basis is required for each drug, including laxatives, in gastric bypass patients 5