Should you stop your GLP-1 before surgery or a colonoscopy?

Having an invasive procedure on your calendar can be plenty unnerving on its own. Then you might remember a scary-sounding caution on your GLP-1 medication label about the risk of food getting into your lungs under anesthesia. 

It’s true that doctors have recommended stopping your GLP-1 before surgery due to the way these medications slow stomach emptying, potentially raising the chance that a sedated patient could breathe in leftover food and drink particles that were unexpectedly still lurking in the stomach. Luckily, the latest evidence paints a slightly different picture, and most people don’t have to choose between canceling their meds or canceling their procedure. That doesn’t mean you’re making that decision on your own — telling your doctors about your prescription well in advance is a critical piece of the puzzle. 

Here’s what to know about the risk vs. benefit of staying on a GLP-1 like Ozempic before surgery or colonoscopy, and exactly what you need to do in the days and weeks before.

Key takeaways:

• GLP-1s slow gastric emptying so food stays in your stomach longer — something that can cause an issue if you are going under general anesthesia or sedation.

• It used to be that people taking GLP-1s were advised to skip a week before having surgery or a colonoscopy. Now guidelines say you can continue taking your GLP-1 medication, but you should fast for 24 hours. 

• It’s important you tell your doctor that you take a GLP-1 before the surgery in case they want you to do a different kind of prep.

Knowing how GLP-1s work to bring about weight loss helps explain why they might cause a concern for patients under anesthesia or sedation. Medications like Ozempic, Wegovy (injectable or pill), Zepbound, Mounjaro, and Foundayo (orforglipron) activate hormone receptors in the brain and gut that help to reduce appetite. They also slow gastric emptying, meaning food can remain in your stomach longer than it otherwise would. That’s part of how these medications help people feel full and eat less.

However, food or liquid sticking around in your stomach is a potential problem when you’re unconscious for surgery. “During anesthesia, there is a brief period when patients are less able to protect their airway,” says Dr. Yen-Yi Juo, M.D., a bariatric surgeon and obesity medicine physician at Legacy Good Samaritan Medical Center in Portland, Oregon. “If food remains in the stomach and comes back up, it can enter the lungs [pulmonary aspiration] and cause a serious complication called aspiration pneumonia.” 

That’s why patients undergoing procedures where they’ll be anesthetized or sedated typically receive instructions not to eat or drink anything within a certain time frame before they arrive — to make sure their stomach is empty. The concern for people taking GLP-1 medications is whether they might still have food particles in the stomach even if they followed the pre-op fasting instructions to the letter.

Up until recently, doctors recommended skipping one or more doses of GLP-1 medication a week prior to surgery, to minimize any gastric emptying issues. But that has now changed. In 2024, a group of medical societies (including the American Society of Anesthesiologists, the American Gastroenterological Association, and the International Society of Perioperative Care of Patients with Obesity) issued guidance advising that most people can continue taking their GLP-1 medication before elective procedures. “Aspiration during surgery is a rare event, and researchers are still gathering data to figure out which approach best balances safety with the benefits of continuing GLP-1 medications,” says Juo. 

Instead of automatically stopping all GLP-1s for everyone, the latest recommendation is for surgeons, anesthesiologists, and prescribers to consider an individual’s risk of having food in their stomach at the time anesthesia is administered and to make a shared decision about how to manage it.

A 2025 update based on new evidence gathered by the Society for Perioperative Assessment and Quality Improvement (SPAQI) adds more details to the guidance. It recommends that patients without significant gastrointestinal symptoms can continue taking their GLP-1 medication, but they should fast (consume only clear liquids and no solid food) for 24 hours before procedures requiring anesthesia. It also advises not consuming carbohydrate-containing clear liquids for up to 8 hours beforehand, depending on their sugar content.

So if you don’t necessarily have to stop taking your GLP-1 medication before a procedure, do you still need to mention it to your doctor? Yes. “It’s very important that you tell the surgeon which medication you’re taking and how long you’ve been on it, so that we know what we need to adjust to set you up for the safest surgery,” says Dr. Edwin Davila, D.O., internal medicine physician and National Academy of Sports Medicine advisory board member. Certain people at certain points in time are more likely to have delayed stomach emptying and may need extra precautions before or during their procedure. These include people who:

• Just started a GLP-1 medication 

• Are in the dose-escalation phase, when their medication dose is being increased

• Are taking higher doses 

• Have significant gastrointestinal symptoms, such as nausea, vomiting or abdominal pain

• Have other medical conditions that can slow stomach emptying

If you have one of these risk factors, your care team might give you different fasting instructions, change their anesthesia approach, or use an ultrasound to check that your stomach is empty before the procedure. Or they might recommend that you temporarily stop your medication, or that you postpone an elective procedure until after your GI symptoms have resolved.

Most people can continue taking their GLP-1 medication before a colonoscopy or endoscopy. “The same concern about delayed stomach emptying applies not only to general anesthesia but also to procedures performed under sedation, such as colonoscopy and upper endoscopy,” says Juo. “However, current guidance generally does not recommend that all patients routinely stop GLP-1 medications before these procedures. Similar to surgery, the approach is based on individual risk factors rather than one-size-fits-all recommendations.”

A colonoscopy has one factor working in your favor: The preparation already involves a liquid diet designed to empty the digestive tract. But it’s still important to tell your care team about your GLP-1 prescription: They’ll have specific instructions about your medication and what types of liquids you can consume during the prep period, which you should follow precisely to minimize the risk of complications.

Tell your surgical, anesthesia, and prescribing teams you’re on a GLP-1 — early

As soon as your procedure is scheduled, make sure everyone involved knows which medication you take, your dose, how often you take it, when you last took it, and whether your dose has recently changed. Let them know whether you’re experiencing any side effects, and update them closer to the procedure if new GI symptoms arise. Don’t assume that one member of your care team will automatically pass the information along to everyone else.

Ask specifically whether to hold a dose or adjust your fasting

Ask your care team what to do with your medication and your diet before the procedure. Depending on your individual risk, you may be able to continue the medication while following modified fasting or liquid-diet instructions.

Don’t stop or change your dose on your own

You can talk with your doctor about pausing your medication before surgery as an extra precaution, even if it’s not absolutely required — but don’t make that change without discussing it first. “Stopping a GLP-1 medication ‘just to be extra safe’ may not provide additional benefits,” says Juo. “On the other hand, stopping treatment can have downsides, such as worsening blood sugar control in people with diabetes or disrupting a dose-escalation plan, since many GLP-1 medications take months to reach their most effective dose.”

Follow your team’s fasting or liquid-diet instructions exactly

If you’re told to fast for 24 hours (or another period of time) before your procedure, be sure you know exactly what that means. For example, are clear liquids that contain carbohydrates (such as fruit juice) allowed? 

If you have diabetes, ask how to manage your blood sugar if you do hold a dose

If your care team decides that you should temporarily stop your GLP-1 medication, ask whether you need to monitor your blood sugar differently or make any other changes. Luckily, the typical pause is only for a week before surgery. “That short amount of time is not long enough to cause a disruption in terms of the systemic benefits of the medication,” says Davila, “meaning patients aren’t likely to experience a dramatic increase in their blood sugar or a complete change in their appetite suppression. It takes longer for those effects to begin to decrease.”

For many people, failing to mention a GLP-1 medication before surgery probably won’t result in a complication. “However, for patients who are at higher risk of delayed stomach emptying, the anesthesia team may not have important information needed to adjust the plan and reduce risk,” says Juo. In some circumstances, a procedure may need to be delayed, or the anesthesia plan may need to change. But there’s no reason not to disclose your GLP-1 to your doctors, since most patients will not need to choose between their medication and their surgery.

If you take a GLP-1 medication and have an upcoming surgery, colonoscopy, endoscopy or another procedure involving anesthesia or sedation, don’t automatically skip your medication. Though GLP-1s can slow stomach emptying, most people who are on a stable dose without significant digestive symptoms can continue their medication before surgery, though some may need to take additional precautions based on their personal risk factors. Tell your surgical, anesthesia, and prescribing teams about your medication early, report any gastrointestinal symptoms, and follow their instructions about medication, fasting, and diet to the letter to minimize the chance of complications.