Anyone booked for a scope or an operation gets asked how long to stop their GLP-1 first, and the honest answer has been that nobody knows. A retrospective study at one center compared three groups having elective upper endoscopy: people not on these drugs, people who kept taking them, and people who held for two weeks [1]. The fasting question this follows from is covered in still food in there after twelve hours.
The continued-use finding is unambiguous and large. Retained stomach contents — solid residue or more than 100 mL of fluid — appeared in 5.83% of those who kept taking the drug, against 0.4% of non-users, an odds ratio of 10.68 (95% CI 3.74–30.55). Six patients in 103, against 63 in 15,902. The motility effect behind it is the same one that makes these drugs work at all, which is why it cannot simply be engineered away — see the break-even against surgeryfor what that mechanism is worth paying for.
The two-week hold group came in at 1.61%, which the authors describe as statistically comparable to not using the drug at all. That is where care is needed.
The finding that should carry most weight for anyone reading this desk is the one that cuts the other way. Obesity, defined here as a BMI of 28 or above, independently raised the risk, and did so even after the full two-week hold — roughly tenfold against non-users. The population that buys these drugs is the population in whom holding them worked least well, which turns the headline on its head for exactly the readers most likely to act on it.
One incidental result is worth knowing if a procedure is being scheduled. Having a colonoscopy at the same sitting was strongly protective, and no retained-contents events occurred at all among those who had held for two weeks and were having both procedures together. The bowel preparation for a colonoscopy empties the stomach as well, which is a practical lever a gastroenterologist can pull.
None of this is a guideline, and a single retrospective series at one center should not be used as one. The decision about how long to hold belongs to whoever is doing the procedure, who needs to know the drug, the dose and how recently it was taken — which is a reason to keep a record of what was actually dispensed, a point that matters more when the seller and the doctor are not the same organization, as discussed in sellers publishing two prices and the dose people stay on.