Gliclazide
๐ฌ Gliclazide is a short-acting sulphonylurea used in the management of Type 2 Diabetes Mellitus (T2DM).
โ ๏ธ Key risk: hypoglycaemia โ especially if meals are delayed, missed, or in elderly patients.
๐ Always check the BNF for up-to-date dosing and cautions.
โ๏ธ Mode of Action
- Stimulates pancreatic ฮฒ-cell receptors โ increased insulin release.
- Inhibits hepatic gluconeogenesis, reducing glucose output from the liver.
- Overall: lowers blood glucose by increasing insulin activity & reducing endogenous glucose production.
๐ Indications
- Type 2 Diabetes Mellitus (T2DM) โ when diet and metformin alone are insufficient.
๐ Dose
- 40โ80 mg pre-meals (max 320 mg/day, usually in divided doses).
- Modified-release (MR) form also available for once-daily dosing.
๐ Interactions
- โ Increased risk of hypoglycaemia with:
- Chloramphenicol
- Sulphonamides, Co-trimoxazole
- Warfarin
- Fibrates
- Alcohol ๐ท can also exacerbate hypoglycaemia.
โ ๏ธ Cautions
- Renal/hepatic impairment โ risk of prolonged hypoglycaemia.
- Obesity โ consider metformin first-line (weight-neutral).
- Switch to variable rate IV insulin infusion (VRIII) in acute illness or perioperatively.
- Care in elderly due to higher hypo risk and impaired counter-regulation.
โ Contraindications
- Type 1 Diabetes Mellitus.
- Ketoacidosis.
- See full BNF for other contraindications.
๐ฅ Side Effects
- ๐ฌ Hypoglycaemia โ sweating, tremor, confusion, seizures (exam classic).
- โ๏ธ Weight gain.
- ๐ฃ GI upset (nausea, diarrhoea).
- ๐ธ Rash, hypersensitivity reactions.
- ๐ฉธ Rare: blood disorders (e.g., agranulocytosis, haemolytic anaemia).
- Hepatic toxicity (rare but important).
๐ง Clinical Pearls
- Preferred sulphonylurea in the UK due to its shorter half-life compared with glibenclamide โ lower risk of severe hypos.
- Good choice for patients with irregular meal patterns (safer than long-acting agents).
- Patients should always be counselled on โhypo rulesโ (carry glucose, donโt skip meals, recognise warning signs).
- Monitor HbA1c every 3โ6 months and review if frequent hypoglycaemia occurs.
๐ References
