Could Your GLP-1 Make Anesthesia More Dangerous?

Anesthesia teams need to know about GLP-1 use before a procedure so they can plan for possible delayed stomach emptying.

Could Your GLP-1 Make Anesthesia More Dangerous?

You’ve followed the instructions. You stopped eating when you were told to. You’re ready for surgery, or perhaps a procedure with sedation. Then comes a question you may not have expected: When was your last GLP-1 dose?

It matters because these medications can slow the movement of food out of your stomach. Fasting is still essential, but it may not always mean your stomach is empty. Under anesthesia, the reflexes that normally help protect your airway are weakened. If stomach contents come back up, they can reach your throat. Less commonly, they can enter your lungs.

A large new study found a reason to take that possibility seriously. It also found a reason to keep it in perspective.

What the study found on GLP-1 use and anesthesia, and what it didn’t

Researchers screened 47,039 patients at 119 UK hospitals who were having procedures under the care of an anesthetist. Of those patients, 1,348 reported using a GLP-1 medication during the preceding three months.

Regurgitation or pulmonary aspiration was reported in 1.41% of patients who reported GLP-1 use, compared with 0.12% of those who did not.

The study reported an unadjusted odds ratio of 11.39 for the combined outcome. Those numbers deserve attention, but “11 times more likely to aspirate” would be the wrong takeaway. Most of the reported events were regurgitation. Actual pulmonary aspiration was reported in two of the 1,348 GLP-1 users.

Regurgitation means stomach contents come back up into the mouth or throat.

Aspiration means they enter the airway or lungs, where they can cause a much more serious problem.

The distinction matters: a study that counts both events together cannot tell you that the higher combined rate was a higher rate of aspiration alone.

So is there a risk? The study found an association worth taking seriously. It did not show that aspiration was common, or prove that a GLP-1 caused every event.

How can you fast and still have food in your stomach?

Fasting instructions still matter, even though GLP-1 medications can slow stomach emptying.

Think of fasting instructions as giving your stomach time to clear what you’ve eaten. GLP-1 medications can slow that process. For some people, food may remain longer than expected even after they’ve followed the usual instructions.

That doesn’t make fasting pointless. Follow the instructions your procedural team gives you. But don’t assume that following them makes your medication history irrelevant.

Other research has found residual stomach contents in some GLP-1 users despite appropriate or extended fasting. Having contents in the stomach is a concern; it does not mean those contents will necessarily come back up or enter the lungs.

Anesthesia teams plan around risks they know about. If they know you use a GLP-1 medication, they can assess your circumstances and decide whether your procedure or anesthesia plan needs any adjustment.

The surprising part happened as patients woke up

A recovery nurse responds when a patient feels sick after anesthesia.

It would be easy to picture this as a risk only when anesthesia begins. In the UK study, 10 of the 19 regurgitation or aspiration events among patients reporting GLP-1 use happened as they were emerging from anesthesia. That’s more than half.

The finding doesn’t mean waking up is dangerous for everyone taking a GLP-1. With only 19 combined events in that group, it cannot establish where an individual patient’s risk is greatest. It does show why the anesthesia team’s planning extends beyond putting someone to sleep. Airway protection while a patient wakes up may matter, too.

Your medication list may be missing the one they need to know about

Medication prescribed outside a hospital system may be missing from its records. Tell your care team what you take.

Tell your surgeon, procedural team and anesthesia provider if you use semaglutide, tirzepatide, or another GLP-1 or GLP-1/GIP medication.

Tell them whether you use it for diabetes, weight management or another reason. Tell them even if a different clinician prescribed it, you obtained it through an online service, or you’ve already paused it.

Don’t count on the hospital’s electronic medication list to answer for you. A prescription from a provider outside that health system may not appear there.

In the UK study, more than 40% of patients reporting GLP-1 use listed a prescription source other than a general practitioner or hospital specialist. That finding doesn’t establish that their hospital records were incomplete, but it makes the case for naming the medication yourself.

If you’ve paused treatment, the team still needs to know what you took and when.

Stopping a medication does not necessarily mean its effects have ended by the day of a procedure. Your clinicians can interpret that history in light of the specific medication and your health.

Should you stop your GLP-1 before surgery?

Before changing a GLP-1 medication, ask your care team for instructions specific to your procedure.

Don’t make that decision from a headline, a social-media post or this article. And don’t stop treatment on your own.

This study wasn’t a trial comparing different instructions for continuing or withholding medication.

Hospitals handled GLP-1 use in different ways, so the results do not establish one schedule that works for every patient or every procedure. Current U.S. multisociety guidance says many patients having elective surgery can continue GLP-1 treatment, while decisions for people at greater risk should be made with their care team.

Stopping treatment can also carry costs, including higher blood sugar for someone using the medication for diabetes.

Contact your surgeon, anesthesia team and prescribing clinician for instructions that account for your procedure, medication and medical history. If you’re having symptoms such as nausea or vomiting, tell them that as well. The useful question is whether your team has the information it needs to make a plan for you.

A warning, with limits

The UK study was prospective, but it was observational. It cannot prove GLP-1 exposure caused the events it recorded. Researchers could not adequately adjust for every difference between people who reported GLP-1 use and those who did not.

Clinicians knew who was using the medications, which may have made them more alert to regurgitation in that group. Some medication use or events may also have gone unreported. Practices varied across the hospitals.

Those limits should temper the frightening relative number. They shouldn’t bury the practical message.

GLP-1 medications offer important benefits to appropriately selected patients. This study is a reminder that a medication affecting your stomach can matter when someone else is responsible for protecting your airway.

Before anesthesia or sedation, make sure your team knows what you take, even if you’ve already paused it. That conversation gives them a chance to plan.

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References

1. Potter TE, et al. Peri-operative glucagon-like peptide-1 receptor agonist use and outcomes: a national prospective multicentre cohort study. Anaesthesia. 2026. Primary study for this article. 

2. Castrillon J, et al. Association between glucagon-like peptide-1 receptor agonist use and peri-operative pulmonary aspiration: a systematic review and meta-analysis. Anaesthesia. 2025.

3. Kindel TL, et al. Multisociety clinical practice guidance for the safe use of glucagon-like peptide-1 receptor agonists in the perioperative period. Surgery for Obesity and Related Diseases. 2024.

4. El-Boghdadly K, et al. Elective peri-operative management of adults taking GLP-1 receptor agonists, GIP agonists and SGLT2 inhibitors: a multidisciplinary consensus statement. Anaesthesia. 2025.

5. Nersessian RSF, et al. Relationship between residual gastric content and peri-operative semaglutide use assessed by gastric ultrasound: a prospective observational study. Anaesthesia. 2024.

6. Sen S, et al. Glucagon-like peptide-1 receptor agonist use and residual gastric content before anesthesia. JAMA Surgery. 2024.

7. Vlaeminck N, et al. Gastric ultrasound in patients receiving semaglutide: a prospective, multicentre, matched control study. Anaesthesia. 2026.

8. Chen Y-H, et al. Postoperative aspiration pneumonia among adults using GLP-1 receptor agonists. JAMA Network Open. 2025.

9. U.S. Food and Drug Administration. Wegovy (semaglutide) prescribing information. 2025. See §5.11, “Pulmonary Aspiration During General Anesthesia or Deep Sedation.”

10. U.S. Food and Drug Administration. Zepbound (tirzepatide) prescribing information. 2025. See §5.10, “Pulmonary Aspiration During General Anesthesia or Deep Sedation.”

Medical disclaimer: This article is for general education and is not medical advice. Do not stop or change a GLP-1 medication based on this article. Before a procedure involving anesthesia or sedation, tell your surgeon and anesthesia team about any GLP-1 medication you currently use or have recently paused, and ask them and your prescribing clinician for instructions specific to you.