Gliclazide

Sulfonylurea·Endocrinology - Oral Antidiabetics

Type 2 Diabetes Mellitus

PBSORALDiamicron, Diamicron MR80 mg tabletS4+1

Max Dose

120 mg MR/day

Half-life

16 h

Hypoglycemia

HIGH RISK

Weight Gain

COMMON

Rapid Summary

Overview

Second-generation sulfonylurea. Forces the pancreas to pump out insulin regardless of blood glucose levels. Highly effective but carries a massive risk of hypoglycemia.

Maximum Dose

Max 120 mg/day (Modified Release) or 320 mg/day (Immediate Release).

Clinical Focus

Must be taken with a meal. If the patient skips a meal, they will suffer a severe hypo.

Bottom Line

Gliclazide is a sulfonylurea with proven efficacy for type 2 diabetes and lower hypoglycaemia risk than glibenclamide, but causes weight gain and hypoglycaemia especially in elderly and renal impairment.

Formulation & Access

Brand Names

Diamicron, Diamicron MR

Oral Routes

Tablets IR (80 mg). Modified Release Tablets (30 mg, 60 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Type 2 Diabetes Mellitus.

Clinical Place

Second-line agent after metformin. Rapidly lowers HbA1c but promotes weight gain and pancreatic burnout over time.

Quick reference

Class & Role

Sulfonylurea — Second-generation sulfonylurea.

Route / Formulation

Tablets IR (80 mg). Modified Release Tablets (30 mg, 60 mg). (Diamicron, Diamicron MR)

Usual Dose & Max

PO 30-120 mg OD with breakfast. Max 120 mg/day (Modified Release) or 320 mg/day (Immediate Release).

Key Indication Doses

Type 2 Diabetes (MR): PO 30-120 mg OD with breakfast. Type 2 Diabetes (IR): PO 40-160 mg BD with meals. Elderly / Renal Impairment: Start at 30 mg MR. Highly sensitive to prolonged hypoglycemia.

Best Uses

Avoid / Cautions

Type 1 Diabetes (requires functioning beta-cells to work), Diabetic Ketoacidosis (DKA). Pregnancy Category C. Causes severe neonatal hypoglycemia.

Key Risks

Endocrine: Severe, prolonged hypoglycemia (can be fatal in the elderly). HIGH — Weight gain (insulin is an anabolic, fat-storing hormone). Gastrointestinal: Mild nausea. Immunological: Sulfa-allergy cross-reactivity (rash).

Key Interactions

Beta-blockers mask the physiological warning signs of a hypo (tremor, tachycardia), leaving only sweating as a warning sign. The patient may collapse without realizing their BSL dropped.

Monitoring

Regular BSL checks on the ward. Withhold if the patient is NBM (Nil By Mouth). Routine HbA1c and U&E.

Clinical Pearl

If a patient on Gliclazide is made 'Nil By Mouth' for surgery or a scan, you MUST withhold their morning dose. The drug forces insulin release regardless of food intake; they will crash.

Access

Diamicron, Diamicron MR80 mg tablet

Brand: Diamicron, Diamicron MR
Formulation: Tablets IR (80 mg)