We had a patient recently who has been on Mounjaro injections to help with weight loss before surgery. We had to postpone her surgery because of an increased risk of aspiration during surgery. We advised that the Mounjaro should be stopped for a month before surgery. There are increasing numbers of people using appetite suppressants like Mounjaro and Wegovy (Ozempic), so I thought I would summarize the current guidelines.
Mounjaro (tirzepatide) and Elective Surgery: UK Patient Guide
Purpose: This guide explains whether and how to take Mounjaro (tirzepatide) before elective surgery such as a joint replacement. It follows UK best practice guidelines from CPOC (Centre for Perioperative Care) and UK Clinical Pharmacy bodies.
Should I stop Mounjaro before surgery?
No – in most cases, you should continue Mounjaro as prescribed, even in the days leading up to your operation. This applies to people taking it for: – Type 2 diabetes – Weight loss (even if you don’t have diabetes)
Why not stop it? – There’s no strong evidence that Mounjaro increases the risk of problems under anaesthetic (like aspiration, where food or fluid gets into the lungs), if you follow standard fasting rules. – Stopping Mounjaro could lead to high blood sugar or weight regain, which may increase surgical risks.
Fasting guidance before surgery: – No solid food for 6 hours before your operation – Clear fluids only (like water or black tea/coffee) up to 2 hours before
These standard fasting rules are usually enough to prevent any anaesthetic complications.
What if I have nausea or feel full for a long time? – Tell your surgical or anaesthetic team. – They may: – Extend your fasting time – Use medication to protect your stomach – Delay your Mounjaro dose by a day (rare)
If you’re taking Mounjaro for diabetes: – Continue taking it unless your team advises otherwise. – Your blood sugar may be monitored before, during, or after the operation.
If you’re taking it for weight loss only: – Still continue unless advised otherwise. – You may also have your blood sugar checked, just in case.
Important: If you are placed on a liver-reduction diet before surgery (e.g. before gallbladder or weight loss surgery), your clinical team might ask you to pause Mounjaro temporarily.
Summary Checklist: ☑ Continue Mounjaro unless told otherwise by your surgeon or anaesthetist
☑ Follow standard fasting rules: 6 hrs for food, 2 hrs for clear fluids
☑ Let your team know if you have symptoms like nausea or bloating
☑ Expect a finger-prick glucose test before surgery, even if not diabetic
Need more help? Ask your anaesthetist, pharmacist, or diabetes specialist for individual advice.
