Overview
Gliclazide is a second-generation sulfonylurea oral antidiabetic agent used in the management of type 2 diabetes mellitus. It stimulates insulin secretion from pancreatic beta cells and improves peripheral insulin sensitivity. Gliclazide has demonstrated antioxidant properties and potential cardiovascular benefits beyond glycemic control.
Mechanism of Action
Gliclazide binds to sulfonylurea receptors (SUR1) on pancreatic beta cells, leading to closure of ATP-sensitive potassium channels, membrane depolarization, calcium influx, and subsequent insulin secretion. It also exhibits extrapancreatic effects including improved peripheral glucose utilization and reduced hepatic glucose production.
Indications
- Type 2 diabetes mellitus (non-insulin dependent diabetes mellitus)
- Adjunct to diet and exercise for glycemic control
Dosage
Initial dose: 40-80 mg daily, taken with breakfast. Maintenance dose: 80-320 mg daily in divided doses. Maximum dose: 320 mg daily. Modified-release formulation (Diamicron MR): 30-120 mg once daily with breakfast. Dose should be individualized based on glycemic response.
Contraindications
- Type 1 diabetes mellitus
- Diabetic ketoacidosis
- Severe renal impairment (eGFR <30 mL/min)
- Severe hepatic impairment
- Hypersensitivity to sulfonylureas or sulfonamides
- Pregnancy
Side Effects
- Hypoglycemia
- Gastrointestinal disturbances (nausea, dyspepsia, diarrhea)
- Headache
- Dizziness
- Skin reactions (rash, pruritus, photosensitivity)
- Hematological effects (thrombocytopenia, leukopenia, agranulocytosis)
- Hepatic enzyme elevation
- Weight gain
Interactions
- Beta-blockers, clonidine, reserpine (mask hypoglycemia symptoms)
- Alcohol (increased hypoglycemia risk, disulfiram-like reaction)
- NSAIDs, salicylates, sulfonamides (increased hypoglycemic effect)
- Thiazides, corticosteroids, oral contraceptives (decreased efficacy)
- Warfarin (altered anticoagulant effect)
- MAO inhibitors, probenecid (increased hypoglycemia risk)