GLP-1 medications and anesthesia: what 2026 fasting guidance says

The old advice was blunt: stop your GLP-1 before surgery. Current guidance is more nuanced. Many patients now stay on the drug and change their preparation instead, usually with a longer or modified fast.

This article covers what the guidance says, what evidence sits under it, and where experts still disagree. One flag before anything else: there is no official “2026 fasting standard.” What 2026 actually brings is an ongoing debate and an update to the evidence, not a new rule.

Why anesthesia teams care about GLP-1 drugs

GLP-1 drugs slow gastric emptying. Food or liquid can sit in the stomach even after a patient follows the usual fasting rules. General anesthesia and deep sedation weaken the reflexes that protect the airway, so anything that comes back up can be drawn into the lungs.

That’s the mechanism. The data on how often it actually happens are much thinner. Two terms get confused:

• Retained gastric contents (RGC): food or fluid still in the stomach. Studies find this more often in GLP-1 users.
• Aspiration: stomach contents entering the lungs. Studies have not shown a measurable rise in this.

Most of the research measures RGC and uses it as a stand-in for aspiration risk. Keep that gap in mind. It runs through the rest of this article.

What the FDA label says

Since November 2024, FDA labels for GLP-1 receptor agonists have carried a warning titled “Pulmonary Aspiration During General Anesthesia or Deep Sedation” (section 5.10 on the labels cited). According to the Ozempic prescribing information, the subsection:

• cites rare postmarketing reports of aspiration in patients with residual gastric contents despite reported adherence to preoperative fasting;
• states that available data are insufficient to say whether changing fasting recommendations or temporarily stopping the drug would reduce retained gastric contents.

The warning was added across the class: Ozempic, Wegovy, Rybelsus, Trulicity, Zepbound and Byetta. The same wording appears on the newer Foundayo (orforglipron) label.

Read the second bullet again. The label does not tell anyone to stop the drug or fast longer. It says the data are not good enough to know whether either step helps. Society guidance fills that gap with specific suggestions, covered below.

The wording above is taken from the Ozempic label. The other labels in the class were not reviewed one by one.

The October 2024 multisociety guidance

The most specific US guidance is an October 2024 multisociety clinical practice guidance from the AGA, ASMBS, ASA, ISPCOP and SAGES, published in Surgical Endoscopy.

Shared decision-making, not a blanket stop

Under this guidance, the decision to continue or hold a GLP-1 receptor agonist belongs to four parties together: the patient, the procedural team, the anesthesia team and the prescriber. Factors that raise the risk:

• the dose-escalation phase;
• higher doses;
• weekly rather than daily formulations;
• current GI symptoms such as nausea, vomiting or abdominal pain;
• comorbidities that affect gastric motility.

If a dose is held, daily formulations are held on the day of surgery and weekly formulations one week before.

Holding has a cost. Stopping the drug can mean lost glycemic control for people with diabetes or weight regain for people treating obesity. For the other side of that trade-off, see our look at what studies show about stopping Ozempic or Wegovy.

Liquid diet, ultrasound and intubation

Where delayed gastric emptying is clinically suspected, the same guidance suggests:

• a liquid diet for at least 24 hours before the procedure;
• point-of-care gastric ultrasound, where available;
• rapid-sequence intubation if retained gastric contents are found.

The authors are upfront about the limits. They call the document clinical practice guidance, not an evidence-based guideline, because perioperative GLP-1 data are limited.

For how these drugs affect stomach function more broadly, our article on GLP-1 drugs and gastroparesis covers a related label topic.

What the 2026 evidence review found

A 2026 systematic review in Cureus is the most useful recent summary. It found 19 clinical studies plus 1 administrative claims study, in mixed adult populations undergoing endoscopy or surgery. The largest cohort was 1,671 people.

The review pooled no data. It rated the evidence moderate-to-low certainty, citing heterogeneity and mostly observational designs, and called for large prospective randomized trials. No randomized trials turned up for this article either.

Retained contents are more common in GLP-1 users

In gastric ultrasound studies of GLP-1 users, the review reported odds ratios for solids in the stomach ranging from 3.8 to 11.3. One cross-sectional study found 73% of semaglutide users had a “full stomach” by ultrasound criteria, versus 7% of controls. The review’s commonly used thresholds were more than 1.5 mL/kg of gastric content, or the presence of solids.

Endoscopy data point the same way. A propensity-matched retrospective study at a single academic center (Endoscopy International Open, 2025) compared 152 GLP-1 patients with 152 matched controls. Retained gastric contents showed up at endoscopy in 12.5% of GLP-1 patients versus 1.3% of controls (P<0.0001).

Risk may differ by who is taking the drug

The same study split the rate by reason for use:

Group	Retained gastric contents
Taking the drug for weight loss	about 23% (P<0.0001 vs controls)
Taking the drug for diabetes	2.6% (not significantly different from controls, P=0.5)

Treat this cautiously. It was a single center. RGC was judged from endoscopists’ qualitative reports, and the study was underpowered to detect dose-dependent effects. Indication, dose and duration are tangled together, so the data cannot say which one drives the difference.

Aspiration itself is not clearly higher

The Cureus review reported administrative claims data showing aspiration-related events in 0.8% of GLP-1 users versus 0.7% of controls (OR 1.07, 95% CI 0.85-1.34). Not statistically significant. Aspiration events were rare across the other studies reviewed.

Rarity cuts both ways. Studies of rare events may be underpowered to detect a small difference in risk, and “no significant difference” is not proof of “no difference.”

A multicenter retrospective cohort from the HCA Healthcare database compared 953 GLP-1 users with 3,289 non-users undergoing elective EGD or colonoscopy (July 2021 to March 2024). No aspiration occurred in either group. GLP-1 users had a lower post-procedural oxygen requirement (1.78% vs 3.74%, p=0.003) and lower mortality (0.1% vs 0.9%, p=0.01).

Don’t read those advantages as protection. The authors attribute them to residual confounding and clinician vigilance. The study did not measure retained gastric content or verify whether the drug was actually withheld, and its data predate the 2023 ASA guidance.

Does a longer fast or a holding period work?

Here the evidence is weakest. Both strategies rest mainly on studies that measured RGC, not aspiration events.

The 24-hour liquid diet

In the Cureus review, one retrospective study found about 1-2% residual gastric content after a 24-hour clear-liquid diet, versus about 10% with standard fasting (OR about 0.13). A separate case series of 57 patients on a “24h solids / 12h liquids” protocol reported no retained solids and no aspiration.

Both findings come from small, single-study observational designs. Neither is randomized evidence. The review also found that prolonged fasting protected against high gastric volume more than the timing of the last GLP-1 dose alone.

Holding the drug for 7-8 days

The review found that withholding a GLP-1 RA for 7-8 days was associated with lower odds of high RGC. One study identified about 7.5 days as a protective cutoff. Reported RGC rates ran about 3% after 7 or more days of withholding and about 40% within 7 days of use. Standard fasting in GLP-1 users gave rates of 5.1-19%.

These figures come from observational studies of varying design and are not directly comparable across studies. The 40% and 3% numbers are not a measured effect of holding.

Gastric ultrasound

Point-of-care ultrasound looks at the stomach directly before anesthesia. The multisociety guidance suggests it where available. As with fasting and holding, research shows it can detect retained contents. It does not establish that using it prevents aspiration.

Where experts still disagree

Professional bodies have not settled on one fasting duration. Statements from the UK, from Australia and New Zealand, and from the US (SPAQI) differ on how long patients should fast, and letters published in early 2026 kept the argument going. This article did not review those primary documents, so it does not describe their specific recommendations.

A 2026 letter in the Brazilian Journal of Anesthesiology marks one end of the spectrum. It argues that GLP-1 RAs delay gastric emptying and increase residual gastric contents, but that this has not translated into measurably higher perioperative aspiration pneumonia, respiratory complications or mortality in the studies it cites. It recommends continuing GLP-1 RAs in most patients with individualized risk assessment.

The letter is a narrative commentary, not original research, and it generated no new data. It shows where one part of the field stands. It is not a settled answer.

What the evidence does and does not support

Supported by the evidence:

• GLP-1 users have more retained gastric contents than non-users in several observational studies.
• Measured aspiration events are rare, and no study reviewed here showed a clear rise.
• Society guidance now favors individualized decisions over a blanket stop.

Not established:

• That a 24-hour liquid diet, a 7-8 day hold or gastric ultrasound prevents aspiration. The findings are small, mostly retrospective and use RGC as a surrogate.
• That findings from endoscopy cohorts apply to major surgery.
• That any one fasting duration is correct. The FDA label itself says there are insufficient data to recommend a change to fasting or dosing.

Until randomized trials exist, the guidance is expert judgment working with limited data. If you are on an oral formulation, daily dosing may change the timing question. Our comparison of oral and injectable semaglutide covers how the formats differ.

Frequently Asked Questions

Do I have to stop my GLP-1 medication before surgery?

Recent multisociety guidance rejects a blanket stop. It calls for a shared decision among the patient, anesthesia team, procedural team and prescriber, weighing the risk of aspiration against loss of glycemic control or weight regain. Risk runs higher in the dose-escalation phase, at higher doses, with weekly formulations and with current GI symptoms. If the drug is held, the 2024 guidance says to hold weekly formulations one week before.

Never stop or change a dose on your own. Follow your care team’s instructions. See the multisociety guidance and the Ozempic prescribing information.

What is the 24-hour liquid diet before anesthesia?

The 2024 multisociety guidance suggests a liquid diet for at least 24 hours beforehand when delayed gastric emptying is suspected. Observational data in the 2026 Cureus review suggest it lowers retained gastric contents to about 1-2%, versus about 10% with standard fasting. That evidence is limited and retrospective. The exact protocol varies by hospital, so ask your own anesthesia team.

Why do GLP-1 drugs matter for anesthesia?

GLP-1 drugs slow gastric emptying, so food or liquid can remain in the stomach despite standard fasting. Under anesthesia, that raises the risk that stomach contents are aspirated into the lungs. The FDA added a warning about this in 2024 based on rare postmarketing reports. Retained contents are more common than aspiration events, and studies have not shown a measurable rise in aspiration.

Do all GLP-1 users carry the same risk?

No. In the endoscopy study by Gu et al., retained gastric contents were about 23% in people taking semaglutide for weight loss and 2.6% in those taking it for diabetes, which was not significantly different from controls. That was a single-center study, and indication, dose and duration are confounded. The multisociety guidance also names dose escalation, higher doses, weekly dosing and GI symptoms as risk factors.

What should I tell my surgical team?

The FDA label instructs patients to tell their healthcare providers about any planned surgery or procedure. Report:

• the medication and dose;
• your dosing day;
• how long you have been on it;
• whether the dose was recently increased;
• any nausea, vomiting or bloating.

Then follow the team’s specific fasting and holding instructions.

This article is for informational purposes only and is not medical advice. Talk to your healthcare provider before starting, stopping, or changing any medication.