Hidden GLP-1 use prompts fresh warning before surgery
07 Oct 2026
The Australian and New Zealand College of Anaesthetists (ANZCA) is asking patients to tell their anaesthetist if they use GLP-1 medicines or peptides before an operation.
These medicines can slow the emptying of the stomach. This means food or other material may remain in the stomach even after a patient has followed standard fasting instructions.
ANZCA said pulmonary aspiration, where stomach contents enter the lungs during anaesthesia, is rare but can be extremely serious and potentially life-threatening.
The warning follows research showing that regurgitation of stomach contents was 11 times more likely in people taking GLP-1 medicines than in those not taking them. The absolute risk remains small.
GLP-1 medicines are becoming increasingly common in Australia, while concerns have also been raised about people using unapproved performance and image-enhancing peptides bought online.
Dr Michael Tam, a member of the RACGP Expert Committee – Quality Care, said the growing use of these medicines gives GPs an opportunity to have open and informed conversations with patients.
He said patients may not always feel comfortable telling their regular GP that they are using medicines obtained elsewhere. However, knowing about all medicines and therapeutic substances a patient is taking is important for safe care.
Dr Tam said GPs generally aim to provide a non-judgemental environment where patients can discuss treatments or substances they may otherwise be reluctant to mention.
ANZCA President Dr Tanya Selak said patients should tell their anaesthetist what they are taking, when they last took it and why they are using it.
The college has updated fasting advice for people preparing for surgery. In general, solid food and non-clear fluids should stop six hours before elective surgery, while clear fluids may be allowed in small amounts until the patient is called to theatre.
However, people taking GLP-1 medicines or peptides may need different instructions because of delayed stomach emptying. Some patients may be advised to have clear fluids only for the day before surgery.
ANZCA also advises patients not to stop their GLP-1 medicine on their own. Instead, they should tell their surgical and anaesthesia team so individual advice can be provided.
Dr Tam said educating patients about the importance of sharing this information is particularly important as access to weight-loss medicines and other peptides continues to grow.
Hidden GLP-1 use prompts fresh warning before surgery
Source: Australian and New Zealand College of Anaesthetists (ANZCA), Racgp