These drugs slow the stomach down. That is part of how they work, and it has a consequence that matters exactly once: on the morning of a procedure under anesthesia, when everyone involved is assuming an empty stomach. A cross-sectional study used gastric ultrasound on 124 patients who had followed standard preprocedural fasting instructions, and found increased residual gastric content in 56 per cent of those taking a once-weekly GLP-1 drug against 19 per cent of those who were not [1]. If you are starting on one of these, this belongs on the same page as the questions your seller has not answered.
The numbers
Among 124 participants (median age 56, 60 per cent female), increased residual gastric content was present in 35 of 62 in the exposed group and 12 of 62 in the control group. After adjustment for confounding, GLP-1 use was associated with a 30.5 percentage point higher prevalence (95% CI 9.9 to 51.2), an adjusted prevalence ratio of 2.48 (95% CI 1.23 to 4.97). Increased content was defined as solids, thick liquids, or more than 1.5 mL/kg of clear liquids on ultrasound.
The part that changes what you should do
The intuitive response is to stop the drug for a while beforehand, and the study looked at that directly. There was no association between the duration of interruption and the prevalence of increased gastric content: adjusted odds ratio 0.86, 95 per cent CI 0.65 to 1.14, an interval comfortably spanning no effect.
That is a single cross-sectional study and it is not the last word. But it means the correct action is not to quietly skip a dose and say nothing. It is to tell the anesthesiologist you are taking the drug, and let them decide on the airway plan and the fasting window. The study’s own conclusion is that current fasting guidance may be inadequate for this group.
Why your seller probably will not raise it
A telehealth seller that never learns you are having surgery cannot warn you about it, and most of the sellers tracked here publish very little about the clinical relationship at all — a gap measured across the market in what sellers will not tell you. Delayed gastric emptying also affects bowel preparation for colonoscopy, which is the other place this comes up, and it applies to both molecules on the seller comparisons.
Two practical notes. Tell every clinician who asks what you take, including the ones who only ask about “medications” and not about weight-loss injections. And if a procedure is coming, raise it early enough that the plan can change — not on the day. The same delayed emptying underlies the nausea most people meet during titration, and it is worth understanding as one mechanism rather than two unrelated problems.