Semaglutide and Surgery: The Anesthesia Question

If you take semaglutide and have a procedure coming up, you have probably gotten conflicting instructions. One clinic says hold it for a week. Another says keep taking it. A third says nothing at all.

That confusion is real, and it has a history. The guidance genuinely changed, in a fairly dramatic way, between 2023 and 2024. Here is what happened, what the evidence actually shows, and what you should raise with your care team.

None of this is medical advice, and none of it replaces the instructions your surgeon and anesthesiologist give you.

Why is semaglutide an issue for anesthesia at all?

Anesthesia has one rule that everything else hangs on: the stomach should be empty. Under general anesthesia or deep sedation, the reflexes that normally keep stomach contents out of your airway stop working. If food or fluid comes back up, it can enter the lungs. That is pulmonary aspiration, and it can cause a serious chemical pneumonitis.

That is why you are told not to eat after midnight. Standard fasting rules assume a normal stomach empties on a predictable schedule.

Semaglutide breaks that assumption. Slowing gastric emptying is a core part of how the drug works. Which means someone can follow the fasting instructions exactly and still arrive with food in their stomach.

The Ozempic label puts it plainly under Warnings and Precautions 5.10: there have been rare postmarketing reports of pulmonary aspiration in people receiving GLP-1 receptor agonists who were undergoing elective surgeries or procedures requiring general anesthesia or deep sedation, and who had residual gastric contents despite reported adherence to preoperative fasting recommendations [4].

The same section then says something unusual for a drug label: available data are insufficient to inform recommendations to mitigate that risk, including whether changing fasting instructions or temporarily stopping semaglutide would reduce retained stomach contents. The label’s only instruction to patients is to tell healthcare providers before any planned surgery or procedure [4]. The Wegovy label carries the same section [11].

That regulatory silence is the whole reason professional societies stepped in.

What did the guidance say in 2023, and what changed?

June 2023. The American Society of Anesthesiologists issued consensus-based guidance after case reports of patients arriving with full stomachs. It recommended holding weekly injectable GLP-1 drugs for a week before a procedure and daily agents on the day of the procedure [3].

That was a precautionary call made quickly on thin evidence, and it created real problems. Holding a diabetes medicine for a week affects blood sugar. Patients had procedures canceled on the day. People on weight-management therapy lost a week of treatment. And for many patients the underlying reason they were having surgery, such as obesity-related joint disease, was the same reason they were on the drug.

October 2024. Five organizations, the ASA plus the American Gastroenterological Association, the American Society for Metabolic and Bariatric Surgery, the International Society of Perioperative Care of Patients with Obesity and SAGES, issued joint multisociety guidance that reversed the default [1][2].

The new position: most patients should continue taking their GLP-1 receptor agonist before elective surgery. Patients at highest risk for significant gastrointestinal side effects should follow a clear liquid diet for 24 hours before the procedure, or take other measures depending on circumstances. Patients without those risk factors may continue their drug [1][2].

The shift was from a one-size-fits-all hold to individualized risk stratification. A parallel consensus statement from the Society for Perioperative Assessment and Quality Improvement, published in the British Journal of Anaesthesia in 2025, took a similarly multidisciplinary approach [10].

What does the evidence actually show?

Two different questions got tangled together, and separating them explains the whole debate.

Question one: do GLP-1 users arrive with more food in the stomach? Yes, clearly.

A systematic review and meta-analysis in Gastrointestinal Endoscopy, covering 23 observational studies and 262,018 patients, found pooled odds of residual gastric contents 4.54 times higher in GLP-1 users (95% CI 3.30 to 6.24), and almost exactly the same odds ratio for procedures having to be stopped early (4.54, 95% CI 3.05 to 6.75). That same analysis found no significant difference in aspiration pneumonia (OR 0.96, 95% CI 0.53 to 1.75), which foreshadows the split described below [5].

The 2025 Anaesthesia meta-analysis, pooling 18 studies with 165,522 patients and 3,831 cases of residual gastric contents, also found a clear increase [7].

And a randomized trial has now tested what a dose hold does. The OCULUS trial, published in JAMA Internal Medicine in March 2026 [12], recruited 68 patients at two Cleveland Clinic sites scheduled for upper endoscopy, endoscopic ultrasound or ERCP between July 2024 and May 2025. After standard fasting instructions, 25% of patients who continued their GLP-1 drug had clinically significant retained gastric volume, compared with 3.1% of those who skipped their last dose before sedation, an absolute difference of 21.9 percentage points (90% CI 7.0 to 36.7) [6].

Two caveats matter before that number gets treated as settled. The published result comes from a prespecified interim analysis of 60 patients, 28 continuing and 32 holding, and the separation was clear enough that the trial stopped early. And it measured retained stomach contents, not aspiration: no unplanned intubation, aspiration, extended monitoring or hospitalization occurred in either arm [6].

The trial also produced a finding that points somewhere other than holding the drug. Among the 25 patients having an upper endoscopy and a colonoscopy, who were therefore on clear liquids the day before for the bowel prep, not one had clinically significant retained gastric volume, whether or not they held their dose. In the upper-endoscopy-only group, where no such diet applied, the gap was much wider than the headline figure: 46.7% continuing versus 5.0% holding [6]. The authors’ conclusion was that clear liquids the day before may mitigate the risk regardless of GLP-1 use, which is the same lever the 2024 multisociety guidance reaches for.

The investigators also reported that patients with retained contents were mostly asymptomatic on the day, questioning whether asking patients how they feel is a valid way to decide who needs a hold [6].

Question two: does that translate into more aspiration? Here the answer is: not measurably, at least not yet.

The 2025 Anaesthesia systematic review pooled nine studies covering 185,414 patients and 471 cases of pulmonary aspiration. GLP-1 exposure was not associated with pulmonary aspiration, with an odds ratio of 1.04 (95% CI 0.87 to 1.25). The authors rated the certainty of that evidence as low [7]. A 2025 review in the Journal of the Endocrine Society reached the same conclusion: despite delayed gastric emptying, retrospective cohort studies using large real-world databases have not consistently identified a GLP-1-associated risk of aspiration or pneumonia for elective surgical and endoscopic procedures [9].

So: more retained food, no measurable increase in the outcome everyone is worried about. Retained contents are a risk factor for aspiration; they are not aspiration.

The reasonable interpretation is that aspiration is rare enough that even large databases may not have the power to detect a modest increase, and that anesthesia teams who know a patient is on a GLP-1 drug may already be managing around it. That is why the guidance is risk-stratified rather than either “hold everything” or “ignore it.”

What about colonoscopies and endoscopies specifically?

Two issues, not one.

The first is the same retained-contents question, since these procedures use sedation. Most of the residual gastric content data actually comes from endoscopy studies, because an endoscope can see directly into the stomach.

The second is unique to colonoscopy: bowel preparation. Gastroenterology commentary has noted that GLP-1 use may be associated with poorer bowel prep quality and a higher need for a repeat colonoscopy [8]. A slower gut is a gut that clears the prep less completely. That matters for whether the procedure achieves anything, quite apart from sedation safety.

The same commentary notes something counterintuitive: one study found patients scheduled for both upper endoscopy and colonoscopy had less gastric residue, presumably because the bowel prep itself cleared the stomach out [8]. Which is a reminder that this literature is still noisy.

What should you actually do before a procedure?

Practical, drawn from the label and the guidance rather than invented:

Tell every clinician involved. This is the one thing the FDA label directly instructs patients to do. Your surgeon, your anesthesiologist, your gastroenterologist, your dentist if sedation is planned. Do not assume it is already in the chart, and do not assume one specialist told another. Name the drug, the dose and when you last took it [4].

Ask specifically who is deciding. The 2024 guidance is explicitly individualized. That means somebody has to actually look at your situation, and it is usually the anesthesia team, often at a pre-op assessment appointment.

Ask which risk group you are in. The guidance’s dividing line is roughly whether you are at higher risk for significant gastrointestinal symptoms. Relevant factors include being in the escalation phase rather than at a stable dose, being on a high dose, and currently having nausea, vomiting, bloating or constipation.

Ask whether a 24-hour clear liquid diet is recommended. This is the multisociety guidance’s preferred mitigation for higher-risk patients, and it is a middle path between holding the drug and doing nothing [1][2].

Do not stop the drug on your own. If you take semaglutide for type 2 diabetes, stopping affects blood sugar. If a hold is appropriate, the team should tell you, and they may adjust other medicines at the same time.

Ask about emergency procedures too. Guidance built around elective surgery does not cleanly apply to urgent situations. Anesthesia teams have other techniques for a patient assumed to have a full stomach, but only if they know.

If you use semaglutide tablets, mention it separately. Daily and weekly dosing behave differently, and the older guidance treated them differently.

What has not changed

Two things are worth repeating, because they get lost.

The FDA label still has no fasting recommendation, even in the May 2026 Ozempic revision [4]. The label says data are insufficient to say whether changing fasting or temporarily stopping the drug would reduce retained gastric contents. Everything about holds and liquid diets comes from professional society guidance, not from the label.

And nobody is saying this risk means people should not take semaglutide. The entire discussion is about managing a few days around a procedure. The aspiration section sits alongside nine other Warnings and Precautions on the Ozempic label, in a drug that also carries indications for reducing cardiovascular events and slowing kidney disease progression.

The short version

• Semaglutide slows stomach emptying, so some people still have food in the stomach after normal fasting. This is well documented, with roughly four-fold higher odds of retained contents and a randomized trial showing 25% versus 3.1% depending on whether the last dose was taken [5][6].
• Studies have not yet shown a measurable increase in actual aspiration events, with a pooled odds ratio of 1.04 across 185,414 patients, though the evidence is rated low certainty [7].
• The ASA recommended holding weekly GLP-1 drugs in June 2023; five societies reversed that default in October 2024 in favor of individualized assessment, with a 24-hour clear liquid diet for higher-risk patients [1][2][3].
• The FDA label offers no fasting guidance and simply tells patients to inform their providers about planned procedures [4].
• Tell your care team, ask who is making the call, and do not stop a prescribed medicine on your own.

Sources

1. Multisociety clinical practice guidance for the safe use of GLP-1 receptor agonists in the perioperative period — ASA, AGA, ASMBS, ISPCOP and SAGES, October 2024
2. New Multi-Society GLP-1 Clinical Practice Guidance Released — American Society of Anesthesiologists, October 29, 2024
3. ASA Consensus-Based Guidance on Preoperative Management of Patients on GLP-1 Receptor Agonists — American Society of Anesthesiologists, June 2023
4. OZEMPIC (semaglutide) injection label — DailyMed / Novo Nordisk, revised May 2026
5. GLP-1 receptor agonist use and the risk of residual gastric contents and aspiration in patients undergoing GI endoscopy — Gastrointestinal Endoscopy, December 2024
6. Hold GLP-1s Before Endoscopy? Clinical Trial Finds Retained Gastric Contents (OCULUS trial) — MedPage Today
7. Association between GLP-1 receptor agonist use and peri-operative pulmonary aspiration: a systematic review and meta-analysis — Anaesthesia, April 15, 2025
8. GLP-1 receptor agonists in endoscopy — AGA, GI and Hepatology News, December 2025
9. Glucagon-Like Peptide-1 Receptor Agonists and Peri-Procedural Aspiration Risk — Journal of the Endocrine Society, July 2025
10. Perioperative management of patients taking GLP-1 receptor agonists: SPAQI multidisciplinary consensus statement — British Journal of Anaesthesia, 2025
11. WEGOVY (semaglutide) Prescribing Information — U.S. Food and Drug Administration, revised June 2026
12. Holding vs Continuing GLP-1/GIP Agonists Before Upper Endoscopy: The OCULUS Randomized Clinical Trial — JAMA Internal Medicine, March 16, 2026