GLP-1 Medications and Surgery: What You Need to Know

By Jade Chapman – Surgical Assistant to Dr Theo Birch, Specialist Plastic & Reconstructive Surgeon (FRACS)

GLP-1 medications such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) are increasingly used for weight management and metabolic health. As more patients present for surgery while taking these medications, it’s important to understand how they may influence your perioperative care.

If you are planning surgery, here is what you need to know to ensure a safe and well-managed experience.

Why GLP-1 Medications Matter in Surgery

GLP-1 medications work by slowing gastric emptying, reducing appetite and improving blood sugar control. While these effects are beneficial for weight loss, they can have implications during anaesthesia.

A slower gastric emptying time means there is a potential for residual stomach contents, even after standard fasting. This increases the risk of aspiration during anaesthesia — a serious but preventable complication.

Australian Fasting Guidelines

Current Australian anaesthetic guidance has evolved to safely manage patients on GLP-1 medications.

In many cases, patients may be advised to:

• Follow a 24-hour clear fluid diet prior to surgery

• Continue their GLP-1 medication as prescribed (unless otherwise directed)

• Adhere strictly to fasting instructions provided by their surgical team

Clear fluids typically include:

• Water

• Clear apple juice

• Black tea or coffee (no milk)

• Electrolyte drinks (without pulp or solids)

  
  

These guidelines are designed to reduce gastric contents and improve safety during anaesthesia.

Do You Need to Stop Your GLP-1 Medication?

In Australia, many patients do not need to stop their GLP-1 medication prior to surgery. However, this is not one-size-fits-all.

Your management plan will depend on:

• The type of procedure

• Your dose and duration of medication

• Your individual risk factors

• The preference of your anaesthetist

This is why individualised assessment is critical.

The Role of Your Anaesthetist

Your anaesthetist plays a key role in ensuring your safety.

Prior to surgery, they will:

• Review your medications (including GLP-1 therapies)

• Assess your fasting status

• Determine your aspiration risk

• Decide on the safest anaesthetic plan

In some cases, they may modify fasting instructions or adjust how your anaesthetic is delivered.

Why Disclosure Is Essential

It is extremely important that you always disclose GLP-1 medications to:

• Your surgeon

• Your anaesthetist

• The pre-admission team

Even if you think it’s not relevant, these medications directly influence:

• Fasting protocols

• Anaesthetic technique

• Surgical timing

• Post-operative care

  
  

Failure to disclose can increase risk and may result in delays or cancellation of your procedure.

What You Can Do to Prepare

To ensure a smooth surgical experience:

• Inform your surgical team of all medications early

• Follow fasting instructions exactly as provided

• Attend your pre-admission or anaesthetic review

• Ask questions if you are unsure about your medication plan

Clear communication and preparation are key to safe outcomes.

Final Thoughts

GLP-1 medications are highly effective and widely used, but they require careful consideration in the surgical setting. With the right preparation, adherence to fasting guidelines and open communication with your care team, surgery can proceed safely and smoothly.

Working alongside Dr Theo Birch, we prioritise patient safety through thorough assessment, clear guidance and collaboration with experienced anaesthetic teams.

Questions About Surgery While on GLP-1 Medications?

If you are planning a procedure and are currently taking a GLP-1 medication, we encourage you to discuss this during your consultation so we can tailor your care appropriately.

Jade Chapman – Nurse Practitioner

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