Independent UK medicine guidance
Mounjaro before surgery and anaesthesia: UK guidance
Tell your surgical and anaesthetic team that you use Mounjaro before any procedure involving general anaesthesia or deep sedation. This includes some dental procedures and endoscopies. Mounjaro slows gastric emptying, which may leave food or fluid in the stomach despite following ordinary fasting instructions.
Why it matters
Mounjaro slows gastric emptying. This may leave food or fluid in the stomach despite following ordinary fasting instructions, creating a potential risk of stomach contents entering the lungs while you are sedated or unconscious.
Should you stop Mounjaro before surgery?
Older online advice sometimes says to stop a weekly medicine for seven days. That is not the current general UK recommendation. Stopping treatment can have consequences, particularly for people using tirzepatide for type 2 diabetes. The correct plan depends on your procedure, symptoms, medical conditions and anaesthetic risk.
What should you tell the hospital?
Give the pre-operative team:
- The name Mounjaro or tirzepatide
- Your current dose
- The date of your last injection
- The day your next injection is due
- Why you take it
- Whether you have nausea, vomiting, bloating, reflux or prolonged fullness
- Whether you have diabetes or gastroparesis
- Any insulin or other diabetes medicines you use
Follow the fasting instructions exactly
Your team may change your eating and drinking instructions or anaesthetic technique after assessing your risk. Follow the instructions issued specifically for your procedure. If they conflict with general information found online, contact the pre-operative team rather than choosing between them yourself.
Tell the hospital if you develop vomiting, abdominal pain, severe reflux or unusual fullness shortly before the procedure. These symptoms may change the risk assessment.
For emergency surgery, tell staff as soon as possible when your last injection was given.
Common questions
Do I need to stop Mounjaro before an operation?
Do not stop it automatically. Current UK guidance says patients should generally continue GLP-1 and GIP/GLP-1 medicines before surgery unless their healthcare team gives different individual instructions. Older advice to stop a weekly medicine for seven days is not the current general UK recommendation.
Why does Mounjaro matter for anaesthesia?
Mounjaro slows gastric emptying, which may leave food or fluid in the stomach despite following ordinary fasting instructions. That creates a potential risk of stomach contents entering the lungs while you are sedated or unconscious.
Does it apply to dental sedation and endoscopy?
Yes. Tell your surgical and anaesthetic team that you use Mounjaro before any procedure involving general anaesthesia or deep sedation, which includes some dental procedures and endoscopies.
Related guides
Sources: MHRA surgery and aspiration safety update • UK multidisciplinary peri-operative guidance • Mounjaro Patient Information Leaflet (eMC)
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