Can semaglutide (glucagon-like peptide-1 receptor agonist) cause dilated loops of duodenum?

Semaglutide and Dilated Loops of Duodenum

Semaglutide can cause dilated loops of duodenum due to its significant effects on gastric emptying and gastrointestinal motility, which may lead to food retention and bowel distension. 1

Mechanism and Evidence

Semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1 RA), significantly delays gastric emptying and affects gastrointestinal motility through several mechanisms:

• Delayed gastric emptying: Multiple studies have demonstrated that patients on semaglutide have significantly higher rates of retained gastric contents despite prolonged fasting periods 1

  • In a retrospective cohort study, 24.2% of patients on semaglutide had increased residual gastric content compared to only 5.1% in the control group (p = 0.001) 1
  • Even after extended fasting (10-14 hours), solid food remains in the stomach 1

• Duodenal effects: The delayed gastric emptying can lead to distension of the duodenum when food eventually passes through, creating dilated loops visible on imaging studies

• Gastrointestinal disorders: Semaglutide is associated with severe constipation and small bowel obstruction/ileus progression 1, 2

Clinical Significance and Complications

The duodenal dilation caused by semaglutide can lead to several serious complications:

1. Small bowel obstruction: Case reports document food-induced small bowel obstruction in patients taking semaglutide 2

2. Aspiration risk: Multiple case reports document regurgitation and pulmonary aspiration in patients on semaglutide despite appropriate fasting 1

   • One patient required postoperative mechanical ventilation and ICU admission 1
   • Another patient developed clinical and radiological evidence of pulmonary aspiration requiring ICU ventilation for one day 1

3. Gastroparesis: Semaglutide can induce or exacerbate gastroparesis, which contributes to duodenal dilation 3

Risk Factors and Monitoring

Certain factors may increase the risk of duodenal dilation with semaglutide:

• Dose-dependent effect: Higher doses (such as 1.7 mg weekly) appear to have stronger effects on gastric emptying 1

• Duration of treatment: Patients on chronic therapy (median 57 months) showed higher incidence of gastric residue 1

• Pre-existing GI symptoms: Patients with pre-existing bloating, nausea, or abdominal discomfort are at higher risk 3

Clinical Implications

For patients on semaglutide:

• Imaging findings: Be aware that dilated loops of duodenum may be an expected finding on imaging studies in patients taking semaglutide

• Procedural considerations: Patients on semaglutide requiring procedures under anesthesia should be considered high risk for aspiration 1

  • Consider extended fasting periods (>12 hours)
  • Consider rapid sequence intubation
  • Be prepared for management of regurgitation

• Monitoring: Watch for symptoms of bowel obstruction including abdominal pain, distension, nausea, and vomiting 2

• Patient education: Inform patients about the importance of thorough chewing of food and avoiding large meals, particularly with high-fiber content 2

Semaglutide's effects on gastrointestinal motility are significant and well-documented. While the medication provides important benefits for weight loss and glycemic control 4, 5, clinicians should be aware of its potential to cause dilated loops of duodenum and related complications.