A new study has found that patients taking GLP-1 medications faced an 11-fold higher risk of regurgitation or aspiration under general anesthesia compared with patients who weren't, prompting the Australian and New Zealand College of Anaesthetists (ANZCA) to issue fresh guidance on October 7, 2026 urging patients to disclose GLP-1 and unapproved peptide use before surgery.

What the Study Found

The research, published in the journal Anaesthesia, drew on United Kingdom data covering more than 47,000 surgical patients, of whom roughly 1,350 had been taking a GLP-1 medication for at least three months before their procedure. Most of the aspiration-related events the researchers identified involved regurgitation, and most occurred as patients were waking up from anesthesia rather than during induction. The study's authors were careful to note that the association may not be fully causal, since obesity and type 2 diabetes, both common among GLP-1 users, independently raise aspiration risk on their own; the data can't fully separate the drug's effect from the health conditions it's often prescribed for.

Why GLP-1 Drugs Raise This Specific Risk

The proposed mechanism is straightforward physiology. GLP-1 medications work partly by slowing gastric emptying, which is part of how they reduce appetite. That same mechanism means a patient's stomach may not be as empty as standard pre-surgical fasting assumes, even after following normal fasting instructions. Under general anesthesia, the body's normal protective reflexes, including coughing and swallowing, are suppressed, so if stomach contents come back up, they can enter the airway and lungs rather than being cleared. That can cause aspiration pneumonia or other serious lung injury, and in rare cases can be fatal.

The New Guidance

ANZCA, through its president, Professor Tanya Selak, is now recommending that patients on GLP-1 medications follow a clear-fluids-only diet for 24 hours before surgery, in addition to the standard six-hour solid-food fast, and that anesthetists proactively ask every patient about GLP-1 use rather than waiting for it to come up, since patients don't always volunteer the information. The guidance extends the same disclosure recommendation to unapproved, compounded, or research-labeled peptides, since several of those, including some marketed for weight loss, work through overlapping or related mechanisms and carry even less documented safety data than approved GLP-1 drugs.

A Pushback on Stopping the Drugs Before Surgery

One widely used precaution came in for direct criticism. About a third of the GLP-1 patients in the study had been instructed to stop their medication roughly a week before surgery, a common practice intended to let gastric emptying normalize. Professor Michael Horowitz, a gastrointestinal researcher at the University of Adelaide who commented on the findings, called that approach "demonstrably stupid," pointing out that delayed gastric emptying from these drugs can persist well beyond a week off the medication, meaning the precaution may not reliably solve the problem it's meant to address. Horowitz also noted that stopping a GLP-1 drug carries its own risk for patients using it to manage type 2 diabetes, and said more research is needed to establish how long it actually takes for normal stomach emptying to return after a patient stops.

What This Means for Patients

This is new evidence refining an area of anesthesia safety that has been under discussion since GLP-1 drugs became widely used, not a reason to avoid needed surgery or to stop a prescribed medication without medical guidance. The clearest, most actionable takeaway from the guidance is disclosure: tell your surgical and anesthesia team about any GLP-1 medication and any peptide product you're taking, approved or not, well before a scheduled procedure, so the team can plan fasting and airway precautions accordingly. Decisions about whether and when to pause a GLP-1 medication before surgery should be made with your prescribing physician and your anesthesia team together, not on your own.

The Bottom Line

A large UK dataset now puts a specific number behind a risk anesthesiologists have been watching for several years: GLP-1 users in this study faced roughly 11 times the aspiration risk of non-users under general anesthesia. The data doesn't prove the drugs alone cause that risk, and it doesn't change who should or shouldn't take a GLP-1 medication. It does make a strong case for telling every member of your care team about GLP-1 and peptide use well ahead of any surgery.