GLP-1 RAs and anaesthetic risks

About GLP-1 RAs

GLP-1 RAs (receptor agonists) include semaglutide (Ozempic, Wegovy) and liraglutide (Victoza). These are medicines commonly used to manage type 2 diabetes and assist with weight loss.

They work by imitating a natural hormone called GLP-1, which helps control blood sugar levels and appetite.

GLP-1 RAs and anaesthetic risks

Gastrointestinal effects

These medicines can cause nausea, vomiting, or delayed stomach emptying.

During surgery, this can pose additional risks such as gastric aspiration (inhaling your stomach contents into your lungs).

The anaesthetic team may have to adjust the way they anaesthetise you to reduce this risk.

Why this matters

Gastric aspiration during anaesthesia is a small risk, but it can lead to:

• Aspiration pneumonia (infection and inflammation of your lungs).
• Airway obstruction leading to difficulty in breathing.
• Hypoxia (low oxygen levels) in your blood. 
• Longer recovery and hospital admission, and increased risk of complications.
• Death (caused by airway obstruction and respiratory failure). This is rare.

Increased risk of low blood sugar (hypoglycaemia)

GLP-1 RAs can lower your blood sugar levels. When combined with fasting before surgery or with other medicines, the risk of hypoglycaemia can increase.

Preparing for surgery if you take GLP-1 RAs

To prepare for surgery, do the following.

• Inform the Pre-Operative Assessment team. Let them know you are taking GLP-1 RAs. They will offer guidance on how to manage your medicine around the time of surgery.
• Adjust your medicine. In most cases you should continue your GLP-1 RA as usual before and after surgery. If you need to skip a dose we will explain this to you at your Pre-Operative Assessment appointment
• Follow fasting instructions. It is important to follow the advice that the Pre-Operative Assessment team gives you about when to stop eating and drinking before surgery.

What to expect on the day of surgery

You can expect the following on the day of surgery.

• Tell your anaesthetist if you are taking GLP-1 RAs. 
• Tell them if you have recently started GLP-1 RAs or adjusted your dose.
• Your anaesthetist will review your medical history and may adjust your anaesthetic plan based on the medicines you take, including GLP-1 RAs. They will discuss this with you.