Your medicines before anaesthesia

Keep taking your usual medicines unless you are told otherwise. Some medicines, including blood thinners, diabetes medicines and GLP-1 receptor agonist medicines, need a plan before an anaesthetic. Bring a complete list of everything you take to your pre-anaesthetic assessment.

Make a complete list

Your anaesthetist needs to know about everything you take, not just prescription medicines. Include:

Bringing your medicines in their original packets on the day is also helpful.

Medicines that often need a plan

Blood thinners

Medicines that thin the blood or stop it clotting, sometimes called anticoagulants and antiplatelet medicines, can increase bleeding. Stopping them can also be risky, depending on why you take them. The decision is made with your surgeon or dentist and the doctor who prescribed the medicine. Do not stop them unless you have been told to.

Diabetes medicines

Fasting changes how much insulin and diabetes medicine you need. You will usually be given specific instructions about doses on the day before and the day of your procedure. Some diabetes tablets, including the class known as SGLT2 inhibitors, may need to be stopped some days beforehand. Ask early so there is time to plan.

GLP-1 receptor agonist medicines

These are weekly or daily injections used for diabetes or weight management. The same advice applies to combined GLP-1/GIP medicines. They slow the emptying of your stomach, which can matter during an anaesthetic.

Current Australian recommendations, published in April 2025 by the Australian Diabetes Society, ANZCA and other professional groups, say:

• Do not stop your medicine unless your doctor tells you to. In most cases it is continued.
• Tell your anaesthetist, surgeon or dentist as early as possible that you take it.
• You may be asked to follow a clear-fluid diet from when you wake up on the day before your procedure.
• Sip Til Send (drinking water until you are called to theatre) is not recommended if you take these medicines.
• If you also use insulin, you may be referred to your diabetes specialist for advice.

You may read overseas advice to stop these medicines a week before surgery. That is not the current Australian recommendation. Follow the advice of your own treating team. ANZCA publishes a patient information sheet on GLP-1 medicines.

Blood pressure and heart medicines

Many are taken as usual on the day, but some are left out on the morning of the procedure. Your anaesthetist will tell you which.

Pain medicines

Keep taking your regular pain medicines unless you are told otherwise, and tell your anaesthetist what you take. It helps them plan pain relief for after your procedure.

Herbal, complementary and traditional medicines

Some can affect bleeding, blood pressure or how anaesthetic medicines work. You may be asked to stop some of them before your procedure.

Contraceptive pills and hormone therapy

Some hormone medicines can increase the risk of blood clots after certain operations. Tell your anaesthetist and surgeon if you take them.

Allergies and reactions

Tell your anaesthetist about any allergies to medicines, antiseptics, latex, foods or dressings, and what happened when you reacted. Also tell them if you, or a blood relative, have ever had a serious reaction or problem during an anaesthetic.

Alcohol and other drugs

Alcohol and other drugs can change how your body responds to anaesthesia and pain relief. Please tell your anaesthetist honestly what you use. This information is confidential and is used only to keep you safe.

On the day

Take the medicines you have been told to take, with a small sip of water. Bring your inhalers and any medicines you might need during the day.

In an emergency, call 000. This information is general and does not replace advice from your treating practitioner.