Information for Professionals

Patients having intravenous sedation must follow the fasting instructions provided for their procedure. As a general principle for adults, a light meal or other solid food is stopped at least 6 hours before anaesthesia or sedation. Clear-fluid instructions should follow the anaesthetist's current protocol and should avoid unnecessarily prolonged fluid fasting. Patients with diabetes, significant reflux or delayed gastric emptying, and those taking GLP-1 or dual GLP-1/GIP therapies require specific consideration. The anaesthetist's individual instructions take precedence.

Apart from medications requiring specific management, particularly SGLT2 inhibitors and GLP-1/GLP-1-GIP therapies, non-insulin glucose-lowering medications are generally continued up to and including the night before the procedure and withheld on the day of anaesthesia or sedation.

This includes metformin, DPP-4 inhibitors, sulfonylureas, meglitinides, alpha-glucosidase inhibitors and thiazolidinediones. Combination tablets must be checked carefully because they may contain an SGLT2 inhibitor or another component requiring different management.

Medication is usually recommenced when oral intake has resumed and it is clinically appropriate. Following major illness, surgery or renal dysfunction, metformin should not be restarted until renal function and the patient's clinical state are satisfactory.

DPP-4 inhibitors such as sitagliptin, linagliptin and saxagliptin have a low intrinsic risk of hypoglycaemia. Under the current general perioperative approach, they are continued until the night before the procedure and omitted on the day of anaesthesia or sedation. Check combination products for metformin or an SGLT2 inhibitor.

Such DPP-4 inhibitors also do not present a risk for hypoglycaemia and should be continued on the day of surgery unless combined with an SGLT2i.

Acarbose acts with meals and is omitted on the day of anaesthesia or sedation while the patient is fasting. It can generally be recommenced when normal oral intake resumes.

As with other non-insulin glucose-lowering medication, individual instructions may differ where diabetes is unstable or fasting is prolonged.

(SGLT2i) – “the flozins”: SGLT2 inhibitors (the “flozins”) can cause perioperative euglycaemic diabetic ketoacidosis, particularly with fasting, dehydration or acute illness. Patients taking these drugs should be identified before the procedure and given specific withholding and restart instructions.

Current ADS–ANZCA guidance distinguishes minor day-stay procedures from procedures involving longer admission or bowel preparation:
‍
• Minor/day-stay procedures: omit the SGLT2 inhibitor on the day of the procedure and minimise the duration of fasting.
• Procedures requiring one or more days in hospital: withhold the SGLT2 inhibitor for the two days before the procedure and on the day of the procedure.
• Procedures requiring bowel preparation, including colonoscopy: withhold for the two days before the procedure and on the day of the procedure.

Do not routinely substitute a fixed metformin regimen when an SGLT2 inhibitor is withheld. Glycaemic management should be individualised, particularly where diabetes is poorly controlled or the drug is withheld for several days. If an SGLT2 inhibitor has not been withheld as recommended, or the patient is unwell, ketones and acid-base status may need assessment and the procedure may need to be deferred. Restart only when the patient is clinically well and eating and drinking normally.

GLP-1 receptor agonists and dual GLP-1/GIP receptor agonists can delay gastric emptying and increase the risk of retained gastric contents during anaesthesia or sedation. Examples include semaglutide (Ozempic®, Wegovy®), dulaglutide (Trulicity®), liraglutide (Victoza®, Saxenda®) and tirzepatide (Mounjaro®). Current Australian multidisciplinary guidance recommends that these medications are not routinely ceased before elective procedures.

For elective procedures, patients should notify the anaesthetist in advance and are generally advised to follow a clear-fluid-only diet for the 24 hours before the procedure, followed by the specified fasting protocol. Additional assessment or aspiration-risk mitigation may be required if this preparation has not occurred or if there are other risk factors for delayed gastric emptying.

Patients should know the name of the medication and the date and time of their last dose. Diabetic patients using insulin may require individual advice during the 24-hour clear-fluid period. The anaesthetist should be contacted before the procedure if there is uncertainty.

Direct oral anticoagulants (DOACs) include apixaban, rivaroxaban and dabigatran. Management depends on the bleeding risk of the dental procedure, the indication for anticoagulation, renal function and the timing of the last dose. Many minimal-bleeding-risk dental procedures can be performed without interrupting anticoagulation.
‍
If anticoagulation needs to be interrupted, the cessation interval should follow current guidance for the specific DOAC and procedural bleeding risk; renal function is particularly important for dabigatran. Bridging with low-molecular-weight heparin is not routinely required for patients taking a DOAC. Dentists should not ask patients to stop a DOAC without an agreed perioperative plan.
‍
‍

Do not ask patients to cease warfarin solely because they are undergoing dental treatment. The decision depends on the bleeding risk of the proposed procedure, the indication for anticoagulation, the patient's thromboembolic risk and the INR. Many minor dental procedures can be performed with warfarin continued when the INR is within the therapeutic range.
‍
Where interruption is required, many patients at low or moderate thromboembolic risk can stop warfarin for the appropriate interval without bridging. Bridging is reserved for selected patients at high thromboembolic risk and should be based on current risk-stratified guidance rather than a fixed regimen.
‍
Patients with mechanical heart valves, recent or recurrent thromboembolism, severe thrombophilia, recent stroke or other complex indications require an individual plan involving the prescribing practitioner, anaesthetist and, where appropriate, cardiology or haematology.
‍
No fixed enoxaparin bridging dose is recommended on this page. If bridging is indicated, the drug, dose and timing must be individualised according to thrombotic risk, bleeding risk, renal function, body size and the planned procedure.
‍
For patients in whom anticoagulation management is uncertain, please contact me before altering therapy. Specialist haematology or cardiology advice can be arranged when required.
‍
The safest approach is to establish the anticoagulation plan before the procedure is booked whenever significant interruption or bridging might be required.