Stopping Ozempic or Zepbound before surgery: what current guidance says

Why GLP-1 medicines matter before surgery

Semaglutide (Ozempic, Wegovy, Rybelsus) and tirzepatide (Mounjaro, Zepbound) slow how fast the stomach empties. That is part of why people feel full. Before general anesthesia or deep sedation, people fast so the stomach is empty. If food is still there, it can come back up and be breathed into the lungs, which is called pulmonary aspiration.

From 2023, case reports described aspiration and regurgitation in fasted patients taking semaglutide.² That prompted the first guidance.

What the 2023 ASA guidance said

In June 2023 the American Society of Anesthesiologists (ASA) published consensus-based guidance, noting that the evidence was sparse. For elective procedures it suggested:¹

• Daily GLP-1 medicines: consider holding them on the day of the procedure.
• Weekly GLP-1 medicines: consider holding them a week before.
• On the day, check for symptoms such as severe nausea, vomiting, bloating or stomach pain, and consider delaying if they are present.
• If the medicine was not held, treat the patient as having a "full stomach" or check the stomach with ultrasound if possible.

What the 2024 multi-society guidance says

In 2024, five groups published joint guidance: the American Gastroenterological Association, the American Society for Metabolic and Bariatric Surgery, the American Society of Anesthesiologists, the International Society of Perioperative Care of Patients with Obesity, and the Society of American Gastrointestinal and Endoscopic Surgeons. The ASA's council formally affirmed its value rather than approving it as its own guideline.² The authors call it guidance, not an evidence-based guideline, because data are limited.

The main points:²

• Shared decision. Whether to continue should be decided by the patient with the procedure, anesthesia and prescribing teams, weighing the medical need for the drug against individual risk.
• Risk factors. Being in the dose-escalation phase, a higher dose, weekly rather than daily dosing, stomach symptoms (nausea, vomiting, abdominal pain, indigestion, constipation), and other conditions that slow the stomach, such as gastroparesis or Parkinson's disease.
• Continuing is often fine. People without these risk factors may continue the medicine before surgery. Holding it only because someone has obesity, without a risk factor, could be weight bias.
• If a hold is chosen. The right length is unknown. The guidance suggests following the original ASA advice: the day of surgery for daily drugs, a week before for weekly drugs. Everyone should still be checked for symptoms on the day.
• Lowering risk. A liquid diet for at least 24 hours beforehand can be used when there is concern about delayed emptying. On the day, teams may use stomach ultrasound or change the anesthesia approach (rapid sequence induction with a breathing tube), or discuss cancelling.

The guidance also lists a reason not to stop casually: pausing can cause high blood sugar in people with diabetes, and bridging to other medicines can be costly and carry its own risks, such as low blood sugar.²

What the drug labels say

The current US labels for Wegovy and Ozempic (section 5.10), and for Zepbound, Mounjaro and Rybelsus (section 5.9), carry a warning titled "Pulmonary Aspiration During General Anesthesia or Deep Sedation." They report rare post-marketing cases of aspiration in people who had food left in the stomach despite following fasting instructions. They state that the data are insufficient to say whether changing fasting or temporarily stopping the drug reduces that risk. The labels instruct patients to tell their healthcare providers before any planned surgery or procedure.³ That is the labels' instruction, not a recommendation to stop.

What studies of stomach contents found

All of these are observational studies, not randomized trials. They show links, not cause and effect.

• Does a 1-week hold empty the stomach? Not reliably, according to some studies. In the US ultrasound study, the length of the pause was not linked to stomach contents.⁴ In the larger Brazilian study, contents looked like non-users' only after a pause of more than 14 days without stomach symptoms, or more than 21 days with symptoms.⁶ The Canadian study, which was small and underpowered, still found contents in 42% after a hold of at least 7 days.⁷
• Longer fasting. In 337 GLP-1 users having upper endoscopy in Michigan, 8.4% had food left in the stomach. Fasting from solids for more than 15 hours was linked to lower odds (adjusted odds ratio 0.33).⁹
• Actual aspiration. A 2025 meta-analysis of 20 retrospective studies (207,708 patients, 23,366 GLP-1 users) found higher odds of retained stomach contents (adjusted odds ratio 3.18) and of aborted upper endoscopy (4.90). It found no clear difference in aspiration events (odds ratio 1.75, confidence interval 0.64 to 4.77). Having a colonoscopy at the same visit, with its liquid prep, was linked to fewer retained contents (0.27).⁸

Aspiration is rare, which makes it hard to study. Retained food is a warning sign, not proof of harm.

What to do before your procedure

• Tell everyone involved that you take a GLP-1: surgeon or endoscopist, anesthesiologist, and the clinician who prescribes it. Do this at booking, not on the day.
• Say which medicine and dose, when you take it, whether you are still increasing the dose, and any nausea, vomiting, bloating or constipation.
• Follow the fasting and medication instructions your team gives you. They may differ from what a friend was told, because the guidance is individual.
• If you are unwell on the day, with vomiting or bad bloating, tell the team before the procedure.

Related: GLP-1 nausea and stomach side effects, missed a GLP-1 dose and Ozempic vs Wegovy vs Mounjaro vs Zepbound.