Glibenclamide ๐
Glibenclamide is a long-acting sulphonylurea used in the treatment of type 2 diabetes mellitus (T2DM).
Although effective, it is now less commonly prescribed due to its prolonged action and higher risk of hypoglycaemia compared to shorter-acting sulphonylureas.
๐ Always check the BNF for latest prescribing guidance.
โ๏ธ Mode of Action
- Stimulates pancreatic ฮฒ-cell receptors โ increased insulin release.
- Inhibits hepatic gluconeogenesis (โ liver glucose output).
- Overall: lowers blood glucose by โ insulin & โ endogenous glucose production.
๐ Indications
- Type 2 Diabetes Mellitus (T2DM) โ when metformin alone is insufficient.
๐ Dose
- Typical: 5 mg mane with food (max 15 mg/day).
- Start low and titrate carefully in elderly or frail patients due to risk of hypoglycaemia.
๐ Interactions
- โ Increased risk of hypoglycaemia when combined with:
- Chloramphenicol, Sulphonamides, Co-trimoxazole
- Warfarin
- Fibrates
- Alcohol ๐ท can also potentiate hypoglycaemia (โdisulfiram-like reactionโ).
โ ๏ธ Cautions
- Obesity โ metformin preferred as first-line.
- Consider switching to variable rate IV insulin infusion (VRIII) in acute illness, perioperatively, or if patient is NBM.
- Higher risk of prolonged hypoglycaemia in elderly patients or those with renal/hepatic impairment.
โ Contraindications
- Type 1 Diabetes (requires insulin).
- Severe renal or hepatic impairment.
- Pregnancy & breastfeeding (insulin preferred).
- See full BNF list for other specific contraindications.
๐ฅ Side Effects
- ๐ค Hypoglycaemia โ especially in elderly or missed meals.
- โ๏ธ Weight gain.
- ๐ฃ GI upset (nausea, diarrhoea).
- ๐ธ Rash, pruritus (allergic reactions).
- ๐ฉธ Rare: blood dyscrasias (e.g., agranulocytosis), liver toxicity.
๐ง Clinical Pearls
- Glibenclamide is long-acting (up to 24h) โ increased risk of severe, prolonged hypos compared with shorter-acting sulphonylureas (e.g., gliclazide).
- In frail elderly, consider safer alternatives (e.g., gliclazide or DPP-4 inhibitors).
- Always advise patients on the โhypo rulesโ: carry glucose tablets/sweets, avoid skipping meals, and monitor blood glucose regularly.
๐ References
