What is the use of Glucagon-like peptide (GLP) after Roux-en-Y gastric bypass surgery?

From the Guidelines

GLP-1 receptor agonists can be used after Roux-en-Y gastric bypass surgery, but with careful consideration, starting at the lowest available dose and titrating slowly to minimize gastrointestinal side effects, as recommended by recent studies 1. When using GLP-1 receptor agonists after gastric bypass surgery, it is essential to consider the potential benefits and risks. The medications, such as semaglutide, liraglutide, dulaglutide, and tirzepatide, should be initiated at the lowest available dose and titrated slowly to minimize gastrointestinal side effects, which may be more pronounced in post-bypass patients. For example, semaglutide might be initiated at 0.25mg weekly and increased gradually based on tolerance. Some key points to consider when using GLP-1 receptor agonists after gastric bypass surgery include:

• Waiting at least 12-18 months after surgery before starting these medications, as this allows for the maximum surgical weight loss effect to be achieved 1.
• Close monitoring for nausea, vomiting, and hypoglycemia is essential, as gastric bypass alters gut hormone physiology and may potentiate GLP-1 effects 1.
• Adequate hydration and anti-nausea medications should be available if needed.
• The rationale for using GLP-1 agonists after bypass is to address weight regain or inadequate weight loss, or to manage persistent diabetes.
• These medications work by slowing gastric emptying, increasing satiety, and improving glycemic control, which can complement the physiological changes already induced by the bypass procedure. It is also important to note that there is limited data on the safe use and/or influence of GLP-1 receptor agonists on glycemia and delayed gastric emptying in the perioperative period, as highlighted in recent guidelines 1. However, the most recent study 1 provides the most up-to-date guidance on the use of GLP-1 receptor agonists after gastric bypass surgery.

From the Research

Use of Glucagon-like peptide (GLP) after Roux-en-Y gastric bypass surgery

• The use of Glucagon-like peptide-1 (GLP-1) receptor agonists after Roux-en-Y gastric bypass surgery has been studied in several research papers 2, 3, 4, 5, 6.
• GLP-1 receptor agonists have been found to be safe and effective in managing postprandial hypoglycemia after bariatric surgery, with no increased risk of adverse events 2, 5.
• The blockade of GLP-1 receptors has been shown to correct postprandial hypoglycemia after gastric bypass surgery, suggesting that GLP-1 plays a role in the development of hypoglycemia in these patients 4.
• GLP-1 analogs have been found to lead to significant weight loss and improve glucose homeostasis, making them a potential alternative to surgery for reducing obesity-related risk factors 6.
• The use of GLP-1 receptor agonists after bariatric surgery may also help to reduce the number of postprandial hypoglycemic episodes and improve glycemic variability 5.

Perioperative management of GLP-1 receptor agonists

• The perioperative management of GLP-1 receptor agonists is important to consider, as they can delay gastric emptying and potentially increase the risk of pulmonary aspiration during general anesthesia 3.
• However, ongoing treatment with GLP-1 receptor agonists has been found to attenuate the effect on gastric emptying, and standard fasting times may suffice to manage the risk of pulmonary aspiration for most patients 3.

GLP-1 and bariatric surgery

• Bariatric surgery, such as gastric bypass, can activate GLP-1 and other gastrointestinal peptide hormones, leading to net reductions in appetite and food intake 6.
• The increased levels of GLP-1 after gastric bypass surgery have been found to suppress appetite and reduce food intake, making GLP-1 a potential therapeutic target for obesity treatment 6.