New Guidelines Rewrite the Rules for GLP-1 Users Facing Surgery or Sedation

As GLP-1 receptor agonists (GLP-1RAs) and dual GLP-1/GIP receptor co-agonists (GLP-1/GIPRAs) become ubiquitous—used by an estimated 0.7% of Australians today with projections nearing 10% by 2030—their peri-procedural implications have become an urgent clinical issue. These drugs slow gastric emptying as a primary pharmacological action, creating a real but incompletely quantified risk of retained gastric contents and pulmonary aspiration during anaesthesia or sedation.

A multidisciplinary expert panel convened by four Australian professional bodies (the Australian Diabetes Society, the Australian and New Zealand College of Anaesthetists, the Gastroenterological Society of Australia, and the Nurses' Association for Clinical Operative Services) reviewed the existing evidence base, including case reports, cohort studies, and mechanistic pharmacology data, to generate consensus practice recommendations. The driving clinical concern is that both short-acting agents (liraglutide, exenatide) and long-acting weekly agents (semaglutide, dulaglutide) profoundly inhibit gastric emptying even with chronic use—contradicting early assumptions that tachyphylaxis would reduce this effect over time. Tirzepatide exhibits a similar gastric-emptying delay, while the GIP component alone has no such effect.

The panel's key finding is that standard pre-operative fasting instructions are insufficient for patients on these agents. A large cohort endoscopy study cited in the guideline found that GLP-1RA use increased the absolute risk of aspiration pneumonia by 0.2% (hazard ratio 1.33; 95% CI 1.02–1.74; P = 0.036), a small but clinically meaningful elevation given the severity of aspiration. Case reports documented retained solid food despite fasting for 20 hours, and retained fluid despite no oral intake for 8 hours.

The panel's core recommendations are: (1) All patients must be screened for GLP-1RA or GLP-1/GIPRA use before any procedure requiring sedation or anaesthesia. (2) These medications should be continued rather than stopped in the peri-procedural period, based on the absence of evidence that cessation reliably restores normal gastric emptying within any predictable timeframe and the risk of glycaemic deterioration with cessation. (3) A mandatory 24-hour clear-fluid diet prior to the procedure, followed by standard 6-hour solid-food fasting, is recommended for all such patients. (4) Where patients cannot comply with or complete the liquid diet, risk stratification via gastric ultrasound or minimally sedated gastroscopy is recommended to directly assess gastric contents before proceeding. (5) Intravenous erythromycin should be considered as a prokinetic agent to facilitate gastric emptying in high-risk situations.

Importantly, the panel explicitly states that the absence of gastrointestinal symptoms (such as nausea or vomiting) cannot be used as a proxy for adequate gastric emptying, since the correlation between GI symptoms and delayed emptying on these agents is weak. Similarly, no safe cessation period could be recommended because of insufficient data on the duration required for gastric emptying to return to baseline after stopping different agents. These represent critical knowledge gaps requiring prospective research.