Fasting and Important Medicines
This page provides general information only. Specific fasting and medication instructions can vary depending on the procedure, your medical conditions, and the preferences of your treating team.
Why fasting matters
Fasting before anaesthesia is important because it helps reduce the risk of stomach contents coming back up into the throat or lungs during sedation or general anaesthesia.
Your hospital or treating team will provide instructions about when to stop eating and drinking. If you are unsure, please clarify this before the day of your procedure.
Generally you will be required to stop eating at least 6 hours prior to surgery and you will be able to continue clear fluids until 2 hours prior to surgery and then continue with sips of water until the time you enter the operating theatre. Some patients, such as those taking ozempic type medications may be required to fast from all but clear fluids for 24hrs prior to surgery. Clear fluids include water, clear teas, clear carbohydrate drinks including clear apple juice, coffee with out milk and clear soup broths.
Important medicines
Most regular medicines can often be continued, but some require special planning before surgery or procedures.
It is particularly important to clarify the plan if you take:
- blood thinners or anticoagulants
- antiplatelet medicines
- diabetes medicines
- weight-loss medicines
- insulin
- steroid medicines
Do not stop or continue these medicines based only on general website information. The safest approach is to confirm the plan with your surgeon, proceduralist, cardiologist, GP, hospital and anaesthetist.
GLP-1 and GLP-1/GIP medicines
Medicines in this group are used for diabetes and weight loss. Common examples include:
- liraglutide (Victoza, Saxenda)
- semaglutide (Ozempic, Wegovy)
- dulaglutide (Trulicity)
- tirzepatide (Mounjaro)
Current joint Australian guidance recommends a 24-hour clear fluid diet before the procedure, followed by the standard 6-hour fast. Routine elective pre-procedure cessation of these medicines is not recommended.
If you take one of these medicines, please make sure your hospital and anaesthetist know this well before the day of your procedure.
SGLT2 inhibitors
SGLT2 inhibitors are used for diabetes and, in some patients, for heart failure or kidney disease. Common examples include:
- dapagliflozin (Forxiga)
- empagliflozin (Jardiance)
- ertugliflozin (Steglatro)
- and in some patients canagliflozin (Invokana)
These medicines need special perioperative planning because they can increase the risk of ketoacidosis around the time of surgery or procedures.
If you take an SGLT2 inhibitor, please make sure this is discussed with your treating team well before your procedure.
Anticoagulants and antiplatelet medicines
Medicines that affect blood clotting are especially important to discuss before surgery or invasive procedures.
Common anticoagulants include:
- apixaban
- rivaroxaban
- dabigatran
- warfarin
- and sometimes injectable medicines such as heparin or enoxaparin
Common antiplatelet medicines include:
- aspirin
- clopidogrel
- aspirin with dipyridamole
- prasugrel
- ticagrelor
The management of these medicines is often highly dependent on:
- the procedure being performed
- why you take the medicine
- your bleeding risk
- your clotting or stroke risk
- whether you have atrial fibrillation, a stent, valve disease, or another cardiac condition
For this reason, it is important that you confirm the plan explicitly with your surgeon or proceduralist and your anaesthetist.
If you are unsure
If you are uncertain about fasting, clear fluids, or any medication instructions, please contact your treating team before the day of surgery. It is always better to clarify early than to arrive unsure on the day.
Further information
Further general information is available from ANZCA, including current information for patients taking GLP-1 medicines.