Side effects

Semaglutide and Surgery: Anesthesia Risk and What to Tell Your Team

Semaglutide slows stomach emptying, so food can remain even after fasting. A 2024 multi-society guidance says most patients continue the drug before elective procedures; the FDA label says data are insufficient to recommend stopping, and patients should tell providers about planned procedures.

Last checked September 14, 2026·12 sources cited·Ozempic Wegovy

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Semaglutide slows how fast the stomach empties [4, 11], so food can still be in the stomach on the day of a procedure even after standard fasting. That leftover food raises the risk of regurgitation and aspiration into the airways and lungs during general anesthesia or deep sedation, which can cause potentially fatal aspiration pneumonia ^[2]. At the same time, large studies have not shown that people on these drugs actually aspirate more often, and multi-society guidance released on October 29, 2024 says most patients can continue their GLP-1 drug before elective surgery [2, 7].

Whether to hold the drug, change the diet, or adjust the anesthesia plan is a decision for the care team, not something to decide alone. The Ozempic and Wegovy labels state that available data are insufficient to recommend any risk-reduction step, including modified fasting or temporarily stopping the drug, and they instruct patients to tell their healthcare providers about any planned surgery or procedure [4, 11]. The 2024 guidance frames the choice as shared decision-making among the patient, the procedural team, the anesthesia team, and the prescribing team ^[1].

Why does semaglutide matter to anesthesia teams?

In the gut, GLP-1 signaling is part of the “ileal brake,” which increases gastric emptying time ^[1]. The Ozempic label notes that the drug delays gastric emptying ^[4], and the Wegovy label says the same ^[11]. If the stomach is not empty when anesthesia or deep sedation begins, stomach contents can be regurgitated and aspirated into the airways and lungs, causing aspiration pneumonia that can be fatal ^[2].

This is a common situation for anesthesia teams: about one in eight U.S. adults use GLP-1 drugs such as Ozempic, Wegovy, Saxenda and Trulicity for diabetes, weight loss or heart problems, according to the American Society of Anesthesiologists (ASA) ^[2].

What do the Ozempic and Wegovy labels say?

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

The label goes on to say that available data are insufficient to inform recommendations to mitigate the aspiration risk, including whether modifying preoperative fasting or temporarily discontinuing Ozempic could reduce retained gastric contents ^[4]. The instruction the label does give is that patients should inform healthcare providers prior to any planned surgeries or procedures [4, 11]. The Wegovy label carries the same section 5.10 warning ^[11]. These aspiration warnings were added to GLP-1 labels in November 2024 ^[7].

On June 29, 2023, the ASA Task Force on Preoperative Fasting issued consensus-based guidance ^[3]. For elective procedures, it suggested that patients on daily dosing consider holding their GLP-1 agonist on the day of the procedure, and that patients on weekly dosing consider holding it a week prior ^[3]. The suggestion applied regardless of the indication (type 2 diabetes or weight loss), the dose, or the type of procedure, and the task force noted the evidence was sparse, limited to several case reports ^[3]. For urgent or emergent procedures, the guidance said to proceed and treat the patient as a “full stomach” ^[3].

The 2023 guidance drew pushback between June 2023 and October 2024 for two main reasons: the potential adverse impact of withholding GLP-1 drugs on pre- and postoperative blood sugar control in people with diabetes, and workflow interruptions when patients who did not know they were supposed to discontinue had to cancel procedures at the last moment ^[9].

What does the October 2024 multi-society guidance say now?

On October 29, 2024, the ASA, 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 released joint guidance [2, 9]. It says most patients should continue taking their GLP-1 drug before elective surgery, and that patients at the highest risk for significant GI side effects should follow a liquid diet for 24 hours before the procedure or take other measures, depending on the circumstances ^[2].

The guidance states that use of GLP-1 drugs in the perioperative period should be based on shared decision-making among the patient, the procedural team, the anesthesia team, and the prescribing team, balancing the metabolic need for the drug against individual patient risk ^[1]. It also warns that withholding GLP-1 drugs only for patients with overweight or obesity could constitute bias and should be avoided [1, 2].

If a hold is chosen, the guidance says the duration to hold therapy is unknown, and it suggests following the original ASA approach: holding the day of surgery for daily formulations and a week prior for weekly formulations. All patients should still be assessed on the day of the procedure for symptoms suggesting delayed gastric emptying ^[1].

Which patients does the 2024 guidance treat as higher risk?

The guidance lists factors that elevate the risk of delayed gastric emptying and aspiration ^[1]:

Escalation phase. Patients early in treatment, while the dose is being increased, are more likely to have delayed stomach emptying. The escalation phase typically lasts four to eight weeks, and the guidance says elective surgery should be deferred until it has passed and GI side effects have dissipated [1, 2].
Higher dose. The higher the dose, the more likely GI side effects are [1, 2].
Weekly formulations. GI side effects are more common with weekly compared to daily formulations ^[1].
GI symptoms. Nausea, vomiting, abdominal pain, dyspepsia and constipation can suggest delayed gastric emptying ^[1].
Other conditions. Gastroparesis, bowel dysmotility and Parkinson’s disease can also slow emptying. The guidance says these risk factors should be assessed with enough advance time before surgery to allow adjustments in preoperative care, including diet modification and evaluation of medication bridging ^[1].

What can the care team do besides stopping the drug?

The 2024 guidance describes several tools [1, 2]:

A liquid diet for at least 24 hours before the procedure, an approach already used before colonoscopy and bariatric surgery, when there is concern for delayed gastric emptying ^[1].
Point-of-care gastric ultrasound on the day of the procedure to assess stomach contents in patients at highest risk. Its use may be limited by institutional resources, variability between users, and credentialing requirements [1, 2].
Rapid sequence induction of general anesthesia with tracheal intubation, weighed against canceling the procedure, through shared decision-making with the patient ^[1].
Delaying surgery, in rare cases where the risk is expected to decrease with time ^[2].

What do studies show about food left in the stomach?

Two meta-analyses published in 2025 found that GLP-1 users are more likely to have residual gastric contents despite fasting:

Analysis	Patients	Outcome	Result
Gastrointestinal Endoscopy, 2025 ^[5]	262,018 (23 observational studies)	Residual gastric contents	OR 4.54 (95% CI 3.30–6.24)
Gastrointestinal Endoscopy, 2025 ^[5]	Same	Premature endoscopy termination	OR 4.54 (95% CI 3.05–6.75)
Anaesthesia, 2025 ^[7]	165,522 (18 studies)	Residual gastric contents	OR 5.96 (95% CI 3.96–8.98), low certainty
Anaesthesia, 2025 ^[7]	1,706 (5 studies)	Residual contents when at least one dose was withheld	OR 0.51 (95% CI 0.33–0.81), very low certainty

The Anaesthesia analysis concluded that patients using GLP-1 drugs are at increased risk of presenting for anesthesia with residual gastric contents, though the available evidence does not indicate this translates to an increased risk of pulmonary aspiration ^[7].

What did the OCULUS randomized trial find?

The OCULUS trial, published in JAMA Internal Medicine in March 2026, was conducted at two tertiary care centers in the Cleveland Clinic system and recruited 68 patients between July 2024 and May 2025; most were taking injectable semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) [6, 12]. A preplanned interim analysis covered 60 patients, 32 who held one dose and 28 who continued, and the trial was stopped early after crossing a preestablished stopping boundary ^[12].

After standard pre-anesthesia fasting, clinically significant residual gastric volume occurred in 25.0% of patients who continued their medication versus 3.1% of those who held a dose, an absolute difference of 21.9% (90% CI 7.0–36.7) ^[12]. In the subgroup of 35 patients having upper endoscopy only, the rates were 46.7% versus 5.0% ^[12]. In the subgroup of 25 patients having both endoscopy and colonoscopy, who were on clear liquids the day before, no patients had clinically significant residual gastric volume ^[12]. No cases resulted in aspiration or unplanned intubation in either group ^[6].

Among patients on weekly medications, those who held their dose for more than 3 days were more likely to have a clear stomach than those who held it 3 days or less (92.7% vs 62.5%) ^[6]. Notably, all patients with retained solid food had no upper GI symptoms, and the investigators said this questions the validity of using symptoms in decision-making ^[6]. The one patient in the hold group with clinically significant residual volume was on daily oral semaglutide (Rybelsus) ^[6]. The trial excluded patients with gastroparesis risk factors other than diabetes and was not powered to detect differences among individual drugs or doses ^[6].

Does semaglutide raise the risk of actual aspiration events?

The studies that counted aspiration events, rather than stomach contents, have not found an increased risk:

The Anaesthesia meta-analysis pooled 9 studies involving 185,414 patients and 471 aspiration cases, and found GLP-1 exposure was not associated with pulmonary aspiration (OR 1.04, 95% CI 0.87–1.25, low certainty) ^[7].
The Gastrointestinal Endoscopy meta-analysis found no significant difference in aspiration pneumonia (OR 0.96, 95% CI 0.53–1.75) ^[5].
A 2025 review in the Journal of the Endocrine Society combined 3 elective surgery studies (risk ratio 1.00) and 4 upper endoscopy studies (risk ratio 1.10) and found no consistent GLP-1-associated risk of aspiration or pneumonia ^[9]. In one of those studies, a parallel analysis of opioids found a risk ratio of 2.68, showing the methodology could detect an increased risk from a motility-slowing drug ^[9].

What about colonoscopy or upper endoscopy specifically?

The Gastrointestinal Endoscopy meta-analysis found a significant reduction in residual gastric contents when upper endoscopy and colonoscopy were done the same day versus upper endoscopy alone (OR 0.28) ^[5]. In the OCULUS trial, the combined-procedure subgroup, which followed a clear liquid diet and bowel preparation, had zero events ^[12].

For colonoscopy itself, published studies suggest GLP-1 use may be associated with lower-quality bowel preparation and a higher need for repeat colonoscopies ^[8]. In a GI and Hepatology News perspective piece, gastroenterologist Dr. Jana Al Hashash, writing about the AGA’s rapid clinical practice update, proposed that patients adhere to a clear liquid diet the day before endoscopy to help decrease gastric residue ^[8]. In the same issue, anesthesiologists Dr. Thomas Hickey and Dr. Ryan Pouliot wrote that propofol sedation, frequently given to a state of general anesthesia with an unsecured airway, is an inherently higher aspiration-risk scenario than surgery in the operating room with a secured airway ^[8]. These are individual authors’ perspectives, not society guidance ^[8]. Whether these drugs increase the likelihood of an inadequate bowel preparation is being studied in the ongoing OCULUS-2 trial ^[6].

What should I raise with my care team before a procedure?

The Ozempic label instructs patients to inform healthcare providers prior to any planned surgeries or procedures ^[4]. The ASA says patients should work with their anesthesiologist, surgeon and prescribing care team to determine whether adjustments can be made so surgery can proceed, or whether the procedure should be delayed until the risk decreases ^[2].

The 2024 guidance adds that risk factors should be assessed early enough before surgery to allow adjustments in preoperative care, such as diet modification and evaluation of whether medication bridging is feasible if stopping is indicated ^[1]. It also notes the tradeoffs: stopping a GLP-1 drug can raise blood sugar in people with diabetes, and bridging therapy may be resource-intensive, cost or insurance prohibitive, and can risk other adverse effects such as hypoglycemia [1, 2].

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Frequently asked questions

How long before surgery is semaglutide usually held when a team decides to hold it?

The 2024 multi-society guidance says the duration of a hold is unknown, and suggests following the original 2023 ASA approach: holding on the day of surgery for daily formulations and one week prior for weekly formulations. All patients should still be assessed for symptoms on the day of the procedure [1, 3].

Do I need to stop Wegovy or Ozempic before a colonoscopy?

Not necessarily. The October 2024 guidance says most patients continue their GLP-1 drug before elective procedures, with the decision made through shared decision-making among the patient and the care teams [1, 2]. Colonoscopy already involves a clear liquid diet and bowel preparation the day before, and studies found lower residual gastric contents with same-day upper endoscopy plus colonoscopy than upper endoscopy alone [5, 12].

Should I tell my anesthesiologist that I take Ozempic?

Yes. The Ozempic and Wegovy labels instruct patients to inform healthcare providers prior to any planned surgeries or procedures [4, 11]. The ASA also says patients should work with their anesthesiologist, surgeon and prescribing team on any adjustments or a possible delay.

What is the 24-hour liquid diet and who is it for?

The 2024 guidance says patients at the highest risk for significant GI side effects should follow a liquid-only diet for 24 hours before the procedure or take other measures. The guidance describes a preoperative liquid diet of at least 24 hours, an approach already used before colonoscopy and bariatric surgery, for patients with concern for delayed gastric emptying.

If I feel fine, does that mean my stomach is empty?

Not reliably. In the OCULUS trial, all patients with retained solid food had no upper GI symptoms, and the investigators said this questions the validity of using symptoms in decision-making. The 2024 guidance nonetheless says all patients should be assessed on the day of the procedure for symptoms suggesting delayed gastric emptying.

Does the guidance differ for emergency surgery?

The 2023 ASA guidance addressed urgent or emergent procedures directly: proceed and treat the patient as a "full stomach," managing accordingly. The 2024 guidance focuses on elective procedures, where scheduling can account for risk factors such as the escalation phase of treatment [1, 2].

Is oral semaglutide (Rybelsus) handled differently?

Rybelsus is a daily formulation, so the 2023 ASA approach for daily dosing was to consider holding it on the day of the procedure. In the OCULUS trial, the single patient in the hold group with clinically significant residual gastric volume was on daily oral semaglutide. The trial was not powered to detect differences among individual drugs or doses.

Does the same apply to tirzepatide (Zepbound, Mounjaro)?

The OCULUS trial covered both GLP-1 and GLP-1/GIP agonists, and most participants were taking injectable semaglutide or tirzepatide; the findings on residual gastric volume applied to the combined group [6, 12]. The 2024 multi-society guidance is written for GLP-1 receptor agonists, and the choice to continue or hold any of these drugs rests with the care team through shared decision-making.

This article summarizes FDA labeling, published research and company information current as of September 14, 2026. It is not medical advice and does not replace a conversation with your own healthcare provider. How we research and verify.