Quick summary
If you take Ozempic, Wegovy, Mounjaro or another GLP-1-based medicine and have a procedure planned, tell the anaesthesia and prescribing teams early. These medicines can delay stomach emptying. Many patients can continue treatment, but the fasting and medication plan must be agreed for the individual procedure.
Why does the anaesthetist need to know?
During general anaesthesia or deep sedation, stomach contents can enter the airway and lungs. This is called aspiration. Delayed stomach emptying can leave contents in the stomach despite usual fasting. The MHRA therefore advises an individual assessment and early disclosure of these medicines, including private prescriptions that may not appear in a hospital record.
This concern also applies to procedures such as endoscopy when deep sedation or general anaesthesia is used. It does not mean every person taking a GLP-1 medicine has food remaining in the stomach or will experience aspiration. Studies of retained stomach contents and studies of actual aspiration measure different outcomes.
Should I stop the medicine?
Do not choose a stopping interval yourself. Current ASA patient guidance says most patients can continue their GLP-1 medicine before surgery. The UK MHRA also advises taking prescribed treatment as usual unless a doctor recommends a change. A universal instruction to stop for one or two weeks does not fit every patient.
Your team must consider the procedure, stomach symptoms, recent dose changes, other conditions and the consequences of withholding treatment. If a pause is recommended, ask for a written plan for glucose monitoring, other diabetes medicines and restarting. Advice from this page should not override the instructions given for your own procedure.
What may change the plan?
- Starting treatment or increasing the dose.
- Nausea, vomiting, abdominal pain, significant constipation or other symptoms suggesting slow stomach emptying.
- Gastroparesis or another condition that affects stomach emptying.
- The type and urgency of the procedure and the planned anaesthetic.
Possible precautions include a specified liquid diet before the procedure, stomach ultrasound where appropriate, a different anaesthetic approach or postponing an elective procedure. These are clinical decisions. Ask exactly which foods or fluids are allowed and when to stop them; “liquid diet” and “clear liquids” are not interchangeable instructions.
A practical checklist for your appointment
- Bring the medicine name, dose, dosing day and date of your last dose.
- Report recent dose increases and digestive symptoms.
- Ask whether to continue, pause or change anything, and who will coordinate the decision.
- Confirm fasting instructions, the diabetes monitoring plan and when treatment should restart.
- If instructions from different teams conflict, contact the preoperative team to resolve them before the procedure.
Emergency procedures
Do not delay emergency care because you have taken a GLP-1 medicine or have eaten. Tell the emergency and anaesthesia teams what you took and when. They can choose precautions appropriate to the urgency and your condition.
Related guides
Read our diabetes medication guides and medical information and emergency-care limits. This article helps you prepare questions; it does not provide an individual surgical clearance or dosing plan.
Sources
- ASA: Diabetes and weight-loss drugs before surgery — patient guidance, reviewed October 2025.
- MHRA: Aspiration risk during anaesthesia or deep sedation — January 2025 safety update.
- UK multidisciplinary perioperative consensus statement — 2025.
Content and source links updated: 11 September 2026.