Glibenclamide, Gliclazide, Glimepiride, Glipizide, Tolbutamide
[Wockhardt, the only UK manufacturer of glibenclamide, have discontinued production. At the current time, this preparation remains in the British National Formulary and has been included in this monograph as unlicensed imports are available for patients in whom a switch to an alternative is inappropriate]
Issues for Surgery
Increased risk of post-operative infection and delayed wound healing due to poor glycaemic control if omitted.
Hypoglycaemia if continued during nil by mouth period.
Advice in the Perioperative period
Sulfonylureas should be taken as normal the day prior to surgery1.
Twice daily dosing – omit the morning dose on day of surgery1
Twice daily dosing – omit both doses on day of surgery1
In the event of emergency surgery and the patient has already taken their sulfonylurea dose(s) monitor blood glucose levels closely and treat any hypoglycaemia accordingly.
Commence variable rate intravenous insulin infusion (VRIII) perioperatively where indicated (see Further Information) and omit sulfonylurea during VRIII treatment1..
Ensure emergency treatment of hypoglycaemia is prescribed i.e. Glucogel® and 20% dextrose. Rapid acting insulin should also be prescribed1, 2.
Restart once eating and drinking normally and VRIII (where applicable) has been stopped1, 2. Due to the risk of hypoglycaemia with sulfonylureas, capillary blood glucose (CBG) should be monitored post-operatively and consideration should be given to omitting or reducing the dose if reduced food intake. Monitor renal function – dose reduction may be necessary if decline in renal function post-operatively.
NB: Patients undergoing afternoon surgery and taking twice daily sulfonylurea will restart their medication the day after surgery, once they are eating and drinking normally and VRIII (where applicable) has been stopped.
Interaction(s) with Common Anaesthetic Agents
None2, 3, 4, 5, 6, 7.
Interaction(s) with other Common Medicines used in the Perioperative Period
Non-Steroidal Anti-inflammatory Drugs (NSAIDs)
Caution with concomitant use of NSAIDs as they may cause hypoglycaemia3, 4, 5, 6, 7.
Clarithromycin slightly increases, and sulfamethoxazole (found in co-trimoxazole) increases, sulfonylurea exposure which may cause hypoglycaemia2, 3, 4, 5, 6, 7. Case reports of hypoglycaemia have been noted with concomitant use of glibenclamide and ciprofloxacin7. Increase CBG monitoring with concomitant use and adjust dose of sulfonylurea if necessary7.
Patients with a planned short starvation period (no more than one missed meal in total) should be managed by modification of their usual diabetes medication, avoiding VRIII wherever possible (although VRIII may be necessary if emergency surgery or in people with poorly controlled diabetes (HbA1c >69mmol/mol))1. Patients expected to miss more than one meal should have VRIII if they develop hyperglycaemia (CBG >12mmol/L)1.