Wegovy (semaglutide 2.4 mg) is a once-weekly GLP-1 receptor agonist licensed in the UK for weight management in adults with obesity or overweight with comorbidities. Whilst effective for weight reduction, Wegovy significantly delays gastric emptying, raising important perioperative safety considerations. Patients scheduled for surgery or procedures requiring anaesthesia must inform their medical team about Wegovy use, as retained gastric contents increase the risk of pulmonary aspiration during anaesthesia. This article examines current UK guidance on withholding Wegovy before procedures, associated anaesthetic risks, and safe reintroduction after surgery.
Quick Answer: Wegovy should typically be withheld for at least one week before elective surgery due to delayed gastric emptying, which increases aspiration risk during anaesthesia.
Wegovy (semaglutide 2.4 mg) is a once-weekly subcutaneous injection licensed in the UK for weight management in adults with obesity (BMI ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) with at least one weight-related comorbidity, such as type 2 diabetes, hypertension, or obstructive sleep apnoea. It is manufactured by Novo Nordisk and was approved by the Medicines and Healthcare products Regulatory Agency (MHRA), with NICE guidance (TA875) published in 2023 recommending its use within specialist weight management services, typically for people with a BMI ≥35 kg/m² (or ≥30 kg/m² in certain circumstances) plus a weight-related comorbidity.
Semaglutide belongs to the glucagon-like peptide-1 (GLP-1) receptor agonist class of medications. It mimics the action of endogenous GLP-1, a gut hormone released after eating. By binding to GLP-1 receptors in the brain, pancreas, and gastrointestinal tract, Wegovy produces several therapeutic effects: it enhances insulin secretion in a glucose-dependent manner, suppresses glucagon release, slows gastric emptying, and reduces appetite through central nervous system pathways that regulate satiety.
The delayed gastric emptying effect is particularly relevant in the perioperative setting. Wegovy can significantly slow the time food remains in the stomach, with case reports suggesting this effect may persist beyond standard fasting periods in some individuals. This pharmacological action raises important considerations for patients scheduled for surgery or procedures requiring anaesthesia, as retained gastric contents increase the risk of pulmonary aspiration during induction or emergence from anaesthesia.
Clinical trials (the STEP programme) have demonstrated that Wegovy produces an average weight loss of approximately 15% of initial body weight over 68 weeks in people without diabetes, and around 10% in those with type 2 diabetes, when combined with lifestyle interventions. However, its effect on gastric motility necessitates careful perioperative planning and communication between patients, prescribers, and anaesthetic teams.
Mounjaro® is the most innovative GLP-1 medication proven to dramatically curb appetite, hunger, and cravings to help professional men achieve substantial weight loss.
Start Here
Wegovy® is a weekly injectable GLP-1 medication with proven effectiveness in reducing appetite, hunger, and cravings to help busy professionals lose significant weight.
Start HereThe American Society of Anesthesiologists (ASA) issued guidance in June 2023 recommending that GLP-1 receptor agonists, including Wegovy, should be withheld before elective procedures. For weekly formulations such as Wegovy, the ASA suggests withholding the medication for at least one week prior to anaesthesia. While this US guidance has influenced practice, UK approaches vary by hospital Trust and local policy.
The rationale for considering a pause relates directly to gastric emptying times. Studies using gastric ultrasound and scintigraphy have shown that some patients taking GLP-1 agonists may have significant gastric residual volume even after standard fasting periods. Case reports have documented solid food remaining in the stomach more than 24 hours after ingestion in patients on semaglutide, despite adherence to nil-by-mouth instructions.
UK practice typically involves:
Elective surgery: Following local Trust policy and anaesthetist advice regarding withholding Wegovy; many centres recommend pausing for 1-7 days before the procedure
Pre-assessment screening: Anaesthetic teams routinely ask about GLP-1 agonist use during pre-operative assessment
Patient communication: GPs and prescribing services should inform patients about the need to discuss treatment with their anaesthetic team before planned procedures
Documentation: Clear recording in medical notes and communication with the surgical team
Importantly, patients using GLP-1 receptor agonists for diabetes should not stop their medication without consulting their diabetes team, as alternative glucose-lowering strategies may be needed.
For emergency or urgent surgery, the decision becomes more complex. Anaesthetists may employ additional protective strategies such as rapid sequence induction, cricoid pressure, or awake fibreoptic intubation techniques. Some centres perform point-of-care gastric ultrasound to assess gastric volume and guide anaesthetic technique, though availability and expertise vary.
Patients should inform their GP, surgeon, and anaesthetist about Wegovy use as soon as surgery is planned. Those attending for procedures should not restart their injection until specifically advised by their medical team.
The primary concern with continuing Wegovy close to anaesthesia is pulmonary aspiration of gastric contents, a potentially life-threatening complication. During induction of general anaesthesia, protective airway reflexes are abolished, and if gastric contents are regurgitated, they can enter the lungs. This can cause aspiration pneumonitis (chemical injury from acidic stomach contents) or aspiration pneumonia (bacterial infection), both of which carry significant morbidity and mortality.
Delayed gastric emptying induced by semaglutide means that even patients who have fasted appropriately may have substantial volumes of food or liquid in their stomach. Case reports and small studies have documented instances where patients on GLP-1 agonists had food residue in their stomach at endoscopy despite fasting for 12–18 hours. The risk appears to vary between individuals based on factors such as dose, duration of treatment, and baseline gastric motility.
Additional perioperative risks associated with Wegovy include:
Hypoglycaemia: Uncommon with GLP-1 agonists alone, but risk increases when combined with insulin or sulfonylureas, particularly in patients with diabetes who are fasting perioperatively
Nausea and vomiting: Common side effects that may complicate post-operative recovery and fluid management
Dehydration: Patients experiencing nausea may have reduced oral intake before surgery
Cardiovascular effects: Semaglutide is associated with a small mean increase in heart rate (approximately 2-3 beats per minute according to the SmPC), which may interact with anaesthetic agents
Several case reports have documented aspiration events in patients on GLP-1 agonists despite standard fasting protocols. While the absolute risk remains uncertain, the potential severity of aspiration has prompted precautionary approaches. Anaesthetists may modify their technique when Wegovy cannot be stopped, using rapid sequence induction, smaller doses of sedative agents, or regional anaesthesia techniques where feasible.
Patients should never stop Wegovy without medical advice for non-surgical reasons, but should always disclose its use when surgery is planned. Patients experiencing active nausea, vomiting, abdominal pain, or known gastroparesis should highlight these symptoms to their anaesthetic team, as they may warrant additional precautions or procedure deferral.
Restarting Wegovy after surgery requires individualised assessment based on the type of procedure, post-operative recovery, and gastrointestinal function. There is no universal protocol, and decisions should be made in consultation with the prescribing clinician.
General considerations include:
Minor procedures (e.g., dental work, endoscopy, minor skin surgery): Wegovy can typically be restarted once normal eating and drinking resume, usually within 1–3 days, but follow your clinician's advice
Major abdominal surgery: Delay restarting until bowel function returns, oral intake is established, and there are no complications such as ileus or anastomotic concerns—often 1–2 weeks post-operatively
Bariatric surgery: Specialist guidance is essential, as GLP-1 agonists may be used therapeutically after some procedures but require careful timing according to bariatric centre protocols
Complicated recovery: Any post-operative nausea, vomiting, delayed gastric emptying, or surgical complications should prompt postponement of Wegovy
Patients should consult their prescribing clinician (usually a GP or specialist weight management service) before restarting. The decision should consider:
Tolerance of oral diet without nausea or vomiting
Absence of post-operative complications affecting the gastrointestinal tract
Adequate hydration and nutritional intake
Clearance from the surgical team if there are any concerns
Dose considerations: After a prolonged interruption, the Wegovy SmPC advises considering restarting at a lower dose and re-titrating gradually. This approach may reduce gastrointestinal side effects and improve tolerability, particularly if there has been an extended interruption or if the patient experienced significant side effects previously.
Patients should be advised to contact their GP if they experience persistent nausea, vomiting, abdominal pain, or inability to tolerate oral intake after restarting Wegovy. These symptoms may indicate complications requiring medical assessment. Clear documentation of the restart date and any dose adjustments should be recorded in medical notes to ensure continuity of care and appropriate monitoring of weight management outcomes.
If you experience any suspected side effects from Wegovy, report them to the MHRA through the Yellow Card scheme (yellowcard.mhra.gov.uk or via the Yellow Card app).
For elective procedures, Wegovy is typically withheld for at least one week before anaesthesia, though local UK hospital policies vary. Always follow your anaesthetist's specific advice and inform your surgical team about Wegovy use during pre-operative assessment.
Wegovy significantly delays gastric emptying, meaning food may remain in the stomach beyond standard fasting periods. This increases the risk of pulmonary aspiration during anaesthesia, when protective airway reflexes are abolished and gastric contents could enter the lungs.
Restart timing depends on your procedure type and recovery. After minor procedures, Wegovy can typically resume once normal eating resumes (1–3 days), whilst major abdominal surgery may require waiting 1–2 weeks until bowel function returns. Always consult your prescribing clinician before restarting.
All medical content on this blog is created based on reputable, evidence-based sources and reviewed regularly for accuracy and relevance. While we strive to keep content up to date with the latest research and clinical guidelines, it is intended for general informational purposes only.
DisclaimerThis content is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional with any medical questions or concerns. Use of the information is at your own risk, and we are not responsible for any consequences resulting from its use.
