Higher Regurgitation Rates Found with GLP-1 Drugs under Anesthesia

Nationwide Study Measures Complication Rates under Anesthesia

Patients taking glucagon-like peptide-1 receptor agonists (GLP-1 RAs) experience an 11-fold higher rate of regurgitation and pulmonary aspiration under anesthesia compared to non-users. Dr. Kariem El-Boghdadly of Guy's and St Thomas' National Health Service (NHS) Foundation Trust and King's College London presented the findings at the Association of Anaesthetists Annual Meeting in Liverpool, with full results published in the journal Anaesthesia.

The observational study evaluated 47,039 adult surgical patients across 119 hospital sites throughout the UK. Researchers identified 1,348 patients (2.9%, or roughly 1 in 36) who had taken medications such as semaglutide or tirzepatide within the three months leading up to their procedure.

Delayed Stomach Emptying Drives the Increased Complication Rate

Slower gastric emptying caused by GLP-1 receptor agonists leaves residual food and fluid in the stomach despite standard pre-surgery fasting. Standard fasting protocols assume an empty stomach at the time of induction, but this drug class directly retards stomach motility to regulate blood sugar and appetite.

In the non-GLP-1 cohort, regurgitation or pulmonary aspiration occurred in 57 out of 45,691 patients, representing a baseline rate of 0.12%. Among patients taking GLP-1 RAs, 19 out of 1,348 patients experienced the complication, yielding a rate of 1.41%, or approximately 1 in 71 individuals. Seventeen of those cases involved regurgitation, while two resulted in pulmonary aspiration into the lungs.

Most Events Occur during Awakening rather Than Induction

More than half of the recorded regurgitation events happened while patients were waking up from anesthesia. Specifically, 53% of the complications occurred during emergence, whereas 13% happened at induction and 13% occurred during the operation itself.

Airway reflexes remain blunted during emergence, which makes late regurgitation a practical management challenge for surgical teams. The findings suggest that monitoring cannot stop once the primary surgical phase ends.

Inconsistent Preoperative Guidance and Sourcing Complicate Care

Perioperative management of GLP-1 receptor agonists varied substantially across the 119 participating surgical sites. Nearly one-third of the patients had been advised to pause their medication before surgery, with most omitting doses for 8 to 14 days, reflecting a standard request to stop the drug for one week.

Prescription routes also contributed to communication gaps between patients and surgical teams. Over 40% of patients taking GLP-1 RAs obtained their prescriptions through online pharmacies or sources other than a general practitioner (GP) or hospital clinic, most often for weight management.

• 40% or more of patients obtained their medication outside traditional GP or hospital prescription channels.
• Roughly one in three patients received specific instructions to pause medication before surgery.
• Dose interruptions typically ranged from 8 to 14 days before the scheduled procedure.

What These Findings Mean for Patients Facing Anesthesia

Patients taking GLP-1 medications should disclose their full prescription history to their surgical team well before any planned procedure. Because fasting alone may not clear the stomach, clinicians may adjust anesthesia techniques, airway management strategies, or pre-procedure medication schedules.

The absolute risk of regurgitation remains low at 1.41%, but the consequence of stomach contents entering the lungs requires clinical vigilance. Anyone preparing for elective or emergency surgery should speak with their surgical and anesthesia providers to establish an individualized perioperative plan.