1. Pharmacology

Gliclazide is a second-generation sulfonylurea that lowers blood glucose by stimulating insulin secretion from pancreatic β-cells. It binds to sulfonylurea receptors (SUR1) on the pancreatic cells, leading to the closure of ATP-sensitive potassium channels, depolarization of the membrane, and influx of calcium, which triggers insulin release.

It also exhibits antioxidant properties, improves microcirculatory function, and has hemovascular protective effects, making it especially beneficial in patients with type 2 diabetes and microvascular complications.

  • Onset of action: ~1–2 hours

  • Duration of action: Up to 24 hours (modified-release formulation)

  • Metabolism: Hepatic (CYP2C9)

  • Excretion: Primarily renal (metabolites)

2. Dosage & Administration

Immediate-release:

  • Initial dose: 40–80 mg once daily, preferably with breakfast.

  • Maintenance: 80–320 mg/day in divided doses (usually 2 doses).

Modified-release (MR):

  • Initial: 30 mg once daily with breakfast.

  • Titration: Increase in increments of 30 mg depending on blood glucose response.

  • Max dose: 120 mg/day (single dose).

Elderly / Renal impairment: Start at lower doses and titrate carefully.

3. Interaction

Potential drug interactions:

  • Potentiates hypoglycemia: with alcohol, NSAIDs, other antidiabetics, MAOIs, beta-blockers.

  • Reduces efficacy: with corticosteroids, thiazides, oral contraceptives, and sympathomimetics.

  • CYP2C9 inhibitors/inducers can affect metabolism.

Food interaction: Delayed or reduced food intake may increase the risk of hypoglycemia.

4. Contraindications

  • Type 1 diabetes mellitus

  • Diabetic ketoacidosis

  • Severe renal or hepatic insufficiency

  • Hypersensitivity to sulfonylureas or sulfonamides

  • Pregnancy and lactation

  • Use with miconazole (oral gel form)

5. Side Effects

  • Common: Hypoglycemia, nausea, vomiting, dyspepsia, abdominal pain, diarrhea, constipation.

  • Rare but serious:

    • Hepatic dysfunction (cholestatic jaundice, hepatitis)

    • Hematologic reactions (anemia, thrombocytopenia, leukopenia)

    • Allergic skin reactions

    • Visual disturbances (transient)

6. Pregnancy & Lactation

  • Pregnancy: Category C. Should be replaced by insulin during pregnancy. Not recommended.

  • Lactation: Contraindicated. It is not known whether gliclazide is excreted in human milk.

7. Precautions & Warnings

  • Risk of hypoglycemia, especially in elderly, malnourished, or those with irregular meals.

  • Monitor in renal and hepatic impairment.

  • Periodic monitoring of blood glucose, HbA1c, and renal/liver function tests.

  • Caution with stress, surgery, or infection—may require temporary insulin.

8. Overdose Effects

  • Symptoms: Severe hypoglycemia—dizziness, confusion, visual disturbances, seizures, coma.

  • Management: Immediate oral glucose or IV dextrose. Hospitalization may be required for long-acting hypoglycemia.

9. Therapeutic Class

  • Oral Antidiabetic Agents

  • Sulfonylureas (Second Generation)

10. Storage Conditions

  • Store below 25°C, in a dry place, protected from light and moisture.

  • Keep out of reach of children.

11. Chemical Structure

  • IUPAC Name: N-(hexahydrocyclopenta[c]pyrrol-2(1H)-ylcarbamoyl)-4-methylbenzenesulfonamide

  • Molecular formula: C15H21N3O3S

  • Molecular weight: ~323.41 g/mol

Structural formula (simplified):

O=S(=O)-NH-C(=O)-N
|
CH3-C6H4— (Attached to a heterocyclic ring)

 

 

  
  
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