GLP-1s Before Surgery: Why Advice Conflicts

This article explains what published guidance says. It is not medical advice, and it does not override anything your surgical or anesthesia team tells you. Follow their instructions, and never change a medication on your own before a procedure.

If your surgeon, your anesthesiologist, and your prescriber gave you three different answers about pausing your GLP-1 before a procedure, that is because the medical societies genuinely disagree with each other. Four separate guidance documents published between 2023 and 2025 reach different conclusions, and the newest one aimed at endoscopy says the opposite of the newest one aimed at surgery (British Journal of Anaesthesia). One instruction is consistent across all of them: tell your anesthesia team you take a GLP-1, and follow the plan they give you.

Who This Helps

This is for anyone on a GLP-1 who has surgery, an upper endoscopy, or a colonoscopy scheduled, and for anyone who has already received instructions that do not match what they read online or heard from another clinician. If you have a different procedure than an endoscopy or colonoscopy planned, you may have received different instructions from your care team.

What Is the One Thing You Must Do?

Tell every clinician involved that you take a GLP-1, including the drug name, your dose, when you last took it, and how long you have been on it. The American Society of Anesthesiologists makes the reason plain in its own patient guidance: "Anesthesiologists cannot take special steps to protect you from these risks if they don't know that you're taking the medication" (ASA patient guidance).

Say it even if nobody asked, and say it again on the day. Surveys of anesthesiologists have found that patients often arrive without having been properly instructed, and that instructions from surgical offices are inconsistent.

Why Does the Advice Conflict?

Because five different bodies have published guidance since 2023, and they do not agree. Laying them side by side makes the pattern visible.

ASA, June 2023: hold the medication. Daily dosing, pause on the day of the procedure. Weekly dosing, pause for a week (ASA).
GI societies, summer 2023: no data support stopping before elective endoscopy (AGA and GI societies).
Multi-society guidance, October 2024: most people can continue, with individual risk assessment rather than a blanket hold (Multi-society guidance).
ASGE, February 2025: for elective endoscopy, hold the medication, 24 hours for daily dosing and at least 7 days for weekly (ASGE).
SPAQI, July 2025: continue the medication, but put everyone on 24 hours of clear liquids rather than only higher-risk patients (British Journal of Anaesthesia).

The authors of that last document said so directly, writing that "the recommendations vary significantly in terms of medication management and preoperative fasting protocols for these patients." The disagreement is on the record, not a misunderstanding by your care team.

What this means for you: if you get conflicting instructions, you are not being told something wrong. Different specialties are following different documents. Ask whose instruction governs, and the answer is almost always the anesthesia team performing your sedation.

What Did the First Randomized Trial Find?

Until 2026 this argument ran on observational data. In March 2026, the first randomized trial compared holding one dose against continuing before upper endoscopy, and it was stopped early because the difference was larger than expected (JAMA Internal Medicine).

Among 60 patients at the interim analysis, looking at clinically significant leftover stomach contents:

Held one dose: 3.1% had clinically significant residual stomach volume.
Continued the medication: 25.0% had clinically significant residual stomach volume.
Continued, and had endoscopy alone without a bowel prep: 46.7% had clinically significant residual volume.
Had clear liquids the day before as part of a combined procedure prep: no patients had clinically significant residual volume.

Two caveats belong with these numbers. The trial measured stomach contents rather than actual harm, and there were no cases of aspiration or unplanned intubation in either group. The authors were explicit that the absence of those events should not be read as proof of safety, since the study was too small to detect uncommon outcomes.

Does Feeling Fine Mean Your Stomach Is Empty?

No, and this is the finding most likely to change practice. In that trial, none of the patients who had clinically significant leftover stomach contents reported any upper digestive symptoms on the day of their procedure. The authors concluded that symptom-based strategies may be insufficient for deciding who is at risk (JAMA Internal Medicine).

That matters because the October 2024 guidance uses current symptoms as one of its risk factors. If you feel completely normal, that is genuinely good news for your comfort and it is not evidence that your stomach has emptied.

Is Colonoscopy a Different Situation?

It is, in two directions at once. The clear-liquid bowel prep appears to protect the stomach, which is why the combined-procedure group in the randomized trial had no significant residual volume.

Working against that, GLP-1 use is associated with worse bowel preparation. In a study across 22 endoscopy units and 6,235 patients, people taking a GLP-1 were significantly more likely to have inadequate bowel prep, which can mean a repeat procedure (Gastrointestinal Endoscopy). Ask your gastroenterologist whether they want you on an extended or modified prep.

Why Might Your Anesthesia Type Change?

This detail rarely reaches patients and it explains a lot of last-minute changes. The precautions used for a patient who may have a full stomach are available with general anesthesia but not with sedation, which is what upper endoscopy and colonoscopy usually use. Because of that, an anesthesiologist may recommend general anesthesia instead of sedation rather than cancelling (ASA patient guidance).

Knowing this ahead of time makes the conversation easier if it comes up on the day.

What Do Nearly All the Documents Agree On?

Despite the disagreement about holding doses, four points recur across the guidance.

Your care team needs to know you take a GLP-1, well before the day.
A liquid or clear-liquid diet for about 24 hours beforehand reduces the risk, and several documents apply it broadly rather than narrowly.
Active nausea, vomiting, bloating, or abdominal pain is a reason to pause and reassess rather than proceed.
Urgent and time-sensitive procedures should not be delayed over this.

Surgeons themselves describe the picture as unsettled. Writing in its July 2026 Bulletin, the American College of Surgeons quoted a surgeon saying "It's still too early right now, I think, for us to really know what the true incidence rate is around adverse events with GLP-1 receptor agonists" (American College of Surgeons).

Questions to Ask Before Your Procedure

I take a GLP-1. Do you want me to hold a dose, and if so, when exactly should my last dose be?
Which team's instructions should I follow if I get different answers from different offices?
What should I eat and drink, and for how long before the procedure?
Will I be under sedation or general anesthesia, and could that change based on my medication?
If I hold a dose, what should I do about my blood sugar, and when do I restart?
For a colonoscopy, do you want a longer or modified bowel prep because I take this medication?

If holding a dose means missing your usual injection day, our post on what happens when you miss a dose covers what to expect, and if a clinician raises changing your dosing pattern, our piece on split dosing explains why that decision belongs with your prescriber.

What We Are Not Telling You to Do

This article does not tell you to hold your medication or to continue it. That call depends on your procedure, your dose, how long you have been taking it, your other conditions, and the anesthesia plan, which is why it belongs to the clinicians who can see all of that.

If your surgeon told you to stop and your prescriber disagrees, do not resolve it yourself. Ask the two offices to talk, or ask to speak with the anesthesia team, since they are the ones managing your airway.

Final Takeaway

Conflicting instructions about GLP-1s and procedures are not a mistake on anyone's part. Five guidance documents since 2023 reach different conclusions, and the two most recent point opposite ways.

The first randomized trial, published in March 2026, found much more leftover stomach content in people who continued their dose, though it saw no actual aspiration events in either group.

The finding worth carrying into your appointment is that feeling fine does not mean your stomach is empty. Symptoms turned out to be a poor guide.

Tell your team early, ask whose instructions govern, and follow those. That single step does more for your safety than anything you can read.

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Frequently Asked Questions

Do I need to stop my GLP-1 before surgery?

It depends on your procedure and your situation, and the guidance genuinely conflicts. A 2023 anesthesiology document advised holding, October 2024 multi-society guidance said most people can continue with risk assessment, and a February 2025 endoscopy society document advised holding for elective endoscopy. Follow the instructions from your own anesthesia team.

How long before a procedure would I stop a weekly GLP-1?

Where holding is advised, the commonly cited interval is one week for weekly dosing and the day of the procedure for daily dosing. Some later guidance questions whether a week is long enough, which is one more reason this decision belongs with your clinicians rather than a general article.

Why did my anesthesiologist change me from sedation to general anesthesia?

The precautions used when a patient may have a full stomach are available with general anesthesia but not with sedation. If there is concern about leftover stomach contents, switching to general anesthesia can be safer than cancelling the procedure.

I feel completely fine, so is my stomach empty?

Not necessarily. In the first randomized trial on this question, none of the patients found to have clinically significant leftover stomach contents had reported any upper digestive symptoms that day. The authors concluded that symptoms alone are not a reliable way to judge risk.

Does taking a GLP-1 affect my colonoscopy prep?

Research suggests it can. In a study of more than 6,000 patients across 22 endoscopy units, people taking a GLP-1 were significantly more likely to have inadequate bowel preparation. Ask your gastroenterologist whether they want you on a longer or modified prep.

GLP-1s Before Endoscopy or Colonoscopy: Why the Advice You Get Conflicts