As GLP-1 use rises, so does concern over aspiration and regurgitation risk during surgery — but major medical societies still don’t agree on how best to manage patients taking the drugs.

Data from the GLIMPSE study presented at the Association of Anaesthetists Annual Meeting in Liverpool and published online in Anaesthesia showed an 11-fold higher rate of regurgitation and/or pulmonary aspiration in surgical patients taking GLP-1s.

“We had no idea how big a problem GLP-1 use was in people having surgery in the UK,” lead author Kariem El-Boghdadly, MBBS, PhD, consultant anesthetist at Guy’s and St. Thomas’ NHS Foundation Trust, London, England, and senior editor of Anaesthesia, told Medscape Medical News. “Most existing data were retrospective, at high risk of bias, or unreliable.”

The GLIMPSE study showed that among 47,039 surgical patients across 119 UK sites, 1 in 36 (1348 patients) were taking a GLP-1, and the incidence of pulmonary aspiration and/or regurgitation in those taking the drug was 1.41% (19/1348; 17 regurgitation events, 2 aspiration) compared with 0.12% in the non-GLP-1 cohort.

The data “indicated what we suspected but had little evidence to support — that the incidence of pulmonary aspiration was probably higher in people taking these drugs, and it was significantly higher than we anticipated,” El-Boghdadly said.

Not everyone agreed with that interpretation. Girish P. Joshi, MD, professor in the Department of Anesthesiology and Pain Management at UT Southwestern Medical Center in Dallas and vice chair of the American Society of Anesthesiologists (ASA) Committee on Practice Parameters, said the paper overstated the risks.

“Concentrating on the incidence of regurgitation is inappropriate,” he told Medscape Medical News. “It is the incidence of aspiration that matters. The study is misleading, as the authors’ conclusions are based on regurgitation. In fact, an honest conclusion should have been that this pragmatic study shows there is no difference in aspiration between patients on GLP-1s or not on GLP-1s.”

Regardless of the perspective, experts agree the risks of regurgitation and pulmonary aspiration are small. “But they are real, and the consequences can be devastating, especially in someone with preexisting lung disease,” Adriana D. Oprea, MD, associate professor of anesthesiology at Yale School of Medicine in New Haven, Connecticut, and chair of the GLP-1 task force for the Society for Perioperative Assessment and Quality Improvement (SPAQI), told Medscape Medical News.

“A young, healthy person might tolerate a minor aspiration event, but for others, the outcome ranges from a minor issue to death,” she said. “More people are going to be on these drugs, with new ones coming with different pharmacology, so this is only going to become a bigger problem in the perioperative arena.”

Guidance in Flux

Variations in guidance and practice reflect an unsettled landscape. GLIMPSE showed wide differences in practice with respect to the perioperative cessation of GLP-1s, although the authors noted the complications occurred despite clinicians tending to select airway management options that might mitigate pulmonary aspiration and regurgitation risks.

Oprea sees the controversy as part of a longer-running split between two schools of thought: modify the drug regimen before surgery or modify the diet. “Stopping the medication is not a guarantee you’ll end up with an empty stomach,” she said. “Even patients who follow standard fasting, with no solids for 8 hours and clear liquids up to 2 hours, can still show up with a full stomach and no symptoms at all. We had stronger data supporting modified fasting than stopping the drug.”

Therefore, in a 2025 consensus statement Oprea chaired, SPAQI advised putting every patient taking a GLP-1 — regardless of dose, indication, or duration of use — on a 24-hour clear liquid diet prior to surgery, an approach also endorsed in Australian and New Zealand guidance and now followed by many US institutions and some private institutions in the UK, Oprea said.

The GLIMPSE findings support her group’s perspective, she noted. “Ninety-five percent of the GLIMPSE patients had eaten solids within 24 hours, and almost half had stopped their GLP-1 for a week, and they still had a high rate of aspiration and regurgitation,” she said. “They relied solely on anesthetic technique to prevent it, and it didn’t fully work.”

A separate US trial, OCULUS, found that continuing a GLP-1 before endoscopy produced clinically significant residual gastric volume in 25% of patients compared with 3.1% among those who held one dose. The trial was admittedly small, but those findings also support the view that stopping the drug helps but isn't sufficient on its own, Oprea added.

The ASA’s original 2023 consensus recommended holding GLP-1s for a day for those on daily dosing or a week for weekly dosing. Gastroenterology societies pushed back almost immediately, and by October 2024, ASA had cosigned a revised multisociety guidance with the American Gastroenterological Association (AGA), the American Society for Metabolic and Bariatric Surgery, the International Society of Perioperative Care of Patients with Obesity, and the Society of American Gastrointestinal and Endoscopic Surgeons.

That guidance moves toward individualized risk assessment, stating that patients not at high risk for delayed gastric emptying and aspiration can continue the drug, with a 24-hour liquid diet reserved for those identified as higher-risk.

Other societies took different approaches. In 2025, the American Society for Gastrointestinal Endoscopy advised holding GLP-1s for 24 hours before outpatient endoscopy in patients on daily doses of the drugs. Also in 2025, the UK’s Association of Anaesthetists declared that patients could continue the drugs throughout the perioperative period and manage risk with anesthesia and airway-management techniques on the day of surgery.

El-Boghdadly sees these variations as reflections of different health systems. “Different organizations have different drivers, as well as different local and regional practices and healthcare priorities,” he said. “Recommendations that call for stopping GLP-1s well before surgery require robust anesthesia assessment services in advance, which not every health system can reliably deliver.”

What Clinicians Can Do Now

There are some points of agreement among the societies — namely, don’t delay urgent/emergent procedures for GLP-1 use, and don’t rely on symptoms alone to rule delayed emptying in or out. Furthermore, clinicians need to know if a patient is taking a GLP-1 and should consider specifically asking them before anesthesia, El-Boghdadly said. In GLIMPSE, 2 in 5 patients did not obtain the drugs from a primary care doctor or specialist.

AGA spokesperson Sarah Olivier, MD, gastroenterologist at Griffin Faculty Physicians, Ansonia, Connecticut, told Medscape Medical News that the current situation “is confusing, leading to disruption and delay in care.” The multi-society guidance tried to reduce the confusion, she said, “by promoting individualized care, evaluating risks of complications vs risk of metabolic effects when stopping the medication, and putting the weight of decision-making on the medical team who has prescribed the medication — if the patients are not obtaining the drugs from nonmedical sources, which is an issue all by itself.”

Olivier combines approaches. Her practice still holds GLP-1s, per ASA’s original 2023 guidance, and also requires a 24-hour clear liquid diet prior to surgery. “This is part of our instructional hand-off provided to all our patients upon scheduling their procedures, and it has proven effective in our setting,” she said.

El-Boghdadly acknowledged that “the plethora of guidelines has been confusing,” but he believes that clinicians “should adhere first to their local institutional guidelines, followed by recommendations from their own national societies or organizations.” Clinicians should not follow guidance from organizations outside of their own countries, which may not account for local factors that impact clinical care, he advised. “I don’t think clinicians in the UK should follow guidelines coming from the US, nor should those in the US follow guidelines from the UK.”

Clinicians also must “personalize care through individual risk assessment,” he said, highlighting that risk needs managing not just at induction but through maintenance and emergence, as GLIMPSE found aspiration occurred most often as patients woke up.

Joshi noted, “Many clinicians have not kept up with the updated ASA recommendations and are still practicing the approach recommended in the original guidance. The multi-society recommendations that are endorsed by the ASA are still valid. The subsequent publications are just noise that confuses average clinicians, leading to variable practice.”

Following SPAQI guidance, Oprea recommends universal preoperative screening for GLP-1 use and a 24-hour clear liquid diet for anyone taking a GLP-1, regardless of whether the drug is also held. “We have no way of identifying which patients are truly at low risk of aspiration,” she said. “Until we do, it’s safer to keep everyone on the modified diet.”

Patients with additional risk factors, such as long-standing uncontrolled diabetes or chronic high-dose opioid use, need individualized, day-of evaluation regardless of GLP-1 status, she added.

‘Evidence Needs to Catch Up’ 

It’s unlikely that guidance will come together any time soon. Randomized trials large enough to settle the aspiration question may not be feasible, Oprea said. “I strongly believe we will not have definitive data ever, only because aspiration is such a rare event. And I don’t think it’s even ethical to do a randomized controlled trial to figure out who’s going to aspirate or not.”

Joshi agreed, noting “It’s going to be extremely challenging to get the [necessary] information.” Not only is the incidence low, but “there are so many variables that influence aspiration in patients on GLP-1s.”

El-Boghdadly said that although “the evidence needs to catch up before guidance can unify, in the UK, we have been discussing whether our existing national, multidisciplinary guidelines warrant revision. Doing this too soon risks further confusing clinicians with further guidelines, but waiting too long risks clinical care that might not be optimal.”

El-Boghdadly declared that he or his institution has received funding from GE HealthCare, and he is also an editor of Anaesthesia. Joshi, Oprea, and Olivier declared having no conflicts of interest.

Marilynn Larkin, MA, is an award-winning medical writer and editor based in New York City whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.