GLP-1s Before Surgery: Why the Anesthesia Team Asks

Somewhere between booking a procedure and lying on the table, someone will ask whether you take a GLP-1. It might be the surgeon, the pre-op nurse, the anesthesiologist on the phone the day before, or a form with a long list of medications on it. If you have wondered why this particular drug gets singled out, and what the right answer is, this article is for you.

The short version, which is also the honest version: there is no universal rule you can look up and apply to yourself. The guidance changed recently and deliberately, in the direction of "it depends". What has not changed, and what you can actually control, is making sure your team has three specific facts.

The concern, in one paragraph

GLP-1 receptor agonists slow gastric emptying. That is the mechanism behind a lot of what these medications do, including the fullness that changes how you eat, and it is the reason they matter before anesthesia. Standard fasting instructions before a procedure assume a stomach empties at a typical rate. If it is emptying more slowly, the stomach may still hold contents at the end of the usual fasting window, and a full stomach is a consideration for a team planning sedation or general anesthesia. That is the whole concern. It is a planning question, not an accusation, and answering it well is how you help.

What the guidance said, and what changed in October 2024

This is a topic where the internet is full of confidently stated rules, many of which are simply out of date. Here is the sequence.

In 2023, the American Society of Anesthesiologists suggested holding weekly GLP-1 medications for about a week before a procedure, and daily ones on the day of the procedure. That guidance circulated widely, and it is still what many people find when they search, which is part of why this subject is confusing.

In October 2024, a joint statement from five professional bodies moved in a different direction. The American Society of Anesthesiologists, the American Gastroenterological Association, 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 together stepped away from blanket holds and toward individualized risk assessment. The statement noted that most patients can continue their GLP-1 before elective procedures, with shared decision-making between the patient, the prescriber, the anesthesia team and the proceduralist.

The societies have also acknowledged that the evidence a one-week hold actually reduces gastric retention remains limited, and practice still varies by center and by procedure type. So two different hospitals can reasonably handle the same patient differently, and both can be following current guidance.

Why that means there is no rule for you to apply

It is tempting to read "most patients can continue" as permission and stop there, or to read the older 2023 guidance as a hold instruction and act on it. Both readings turn a clinical judgment into a self-prescription, and neither is what the statement supports.

Individualized assessment means the decision depends on things a website cannot know: which medication and dose you are on, how recently it was increased, whether you are currently having nausea or vomiting, what kind of procedure you are having, what type of anesthesia is planned, what other conditions you have, and how your particular center approaches it. Those variables are the reason the guidance moved away from a single number of days in the first place.

So the practical instruction is short and it is the same for everybody: tell your surgical and anesthesia team that you take a GLP-1, and let them decide. Do not hold, skip, delay or resume a dose on your own, before or after. If a clinician gives you an instruction, follow that instruction rather than something you read, including this.

GLP 1 Tracker AppYour medication, current dose and exact last dose date, ready to read out at the pre-op visit. Free, private, and never gives dose advice. Get the app

The three facts your team always needs

Whatever your center decides, the inputs are the same, and this is the part you can prepare perfectly.

• The medication. The brand name and, if you know it, the generic: Ozempic or Wegovy (semaglutide), Mounjaro or Zepbound (tirzepatide), Trulicity (dulaglutide), Saxenda or Victoza (liraglutide), Rybelsus (oral semaglutide), and so on. If you are on a compounded product, say so explicitly, because the details differ.
• Your current dose. Not just the medication, the amount, and whether you have recently moved up a step. A dose increase two weeks before a procedure is exactly the kind of context a team wants.
• The exact date of your last dose. This is the one that matters most and the one that memory handles worst.

That last point deserves a moment. "About a week ago, I think" is the answer most people give, and it is often wrong by a couple of days in either direction. On a weekly medication, a couple of days is not a rounding error: semaglutide has a half-life of about a week and tirzepatide about five days, so where you sit relative to your last injection is a real variable. Our guides to semaglutide levels and tirzepatide levels explain what happens between shots, and why a date is more informative than a rough estimate.

A dose log answers all three questions in seconds. That is the honest, unglamorous case for tracking here: not that an app helps with the medical decision, but that it makes you a precise witness to your own treatment at the one appointment where precision counts. It is the same reason we recommend bringing data to appointments generally.

This comes up for endoscopy and colonoscopy too

People tend to think of "surgery" as an operating room, but the same considerations apply to procedures involving sedation, including endoscopy and colonoscopy. Those are common, they are frequently booked through a different department than your prescriber, and the notes do not always travel with you.

Say it twice: once when the procedure is booked, and again at any pre-procedure call or check-in. It costs nothing to repeat and it closes the most common gap, which is a team that simply did not know. Bowel preparation instructions for a colonoscopy are their own conversation, and one worth having with the ordering clinician if you are on a medication that slows your gut.

If the team does ask you to change something

Some centers, for some patients and some procedures, will ask you to delay or hold a dose. If that happens, three things follow.

• Get it in writing if you can, or at least write it down yourself: which dose, which date, and what to do afterward. Instructions given verbally in a busy pre-op clinic have a way of blurring by the time you get home.
• Log what actually happened. If a dose was held, record that, so your history stays accurate rather than showing a mysterious gap you cannot explain three months later.
• Ask when to take the next one. Do not work it out yourself. If a dose ends up late, the label windows differ by medication, and our guide to a missed GLP-1 dose summarizes them as background. Use it to understand what your team tells you, not to make the call. And never take a double dose to catch up.

Once you are back on schedule, the weekly rhythm resumes as before, and the ordinary habits of tracking a weekly shot pick up where they left off. If your team paused the medication for a stretch and later restarts it, they may adjust the ladder; that too is their call, described in our titration guide.

The takeaway

The reason anesthesia teams ask about GLP-1s is straightforward: these medications slow the stomach, and fasting rules assume they do not. The reason there is no simple answer online is that the guidance deliberately moved, in October 2024, from a one-size hold to individualized assessment, with most patients able to continue before elective procedures and the decision made jointly by the people who know your case.

Your job is not to work out the rule. It is to make sure nobody has to guess: name the medication, state the current dose, give the exact date of the last one, mention it for endoscopies and colonoscopies too, and then do what your team tells you. If your dose log can produce that date in five seconds at the pre-op desk, it has already earned its place on your phone.