Glimepiride + Metformin + Voglibose Tablets

Mechanism

Metformin belongs to the class of biguanides and used in the management of type 2 diabetes mellitus. Metformin is the insulin sensitizer and reduces insulin resistance. Metformin is beneficial in obese patients. Metformin prevents the hepatic glucose production, increases the intestinal absorption of the glucose and inhibit peripheral utilization of the glucose When administered orally, it half absorbed through intestine and it takes about 7 hours to reach maximum concentration in plasma. Presence of food decreases the absorption of metformin. When 800mg of metformin was administered, the volume of distribution was found to be 654 ± 358 L and is negligibly bound to plasma protein. Metformin is excreted in unchanged form mainly in urine and the half-life is 17.6 hours.

Glimepiride stimulates the beta cells in pancreas to secrete insulin and improves the sensitivity of peripheral tissues to insulin to increase peripheral glucose uptake, thus reducing plasma blood glucose levels and glycated hemoglobin (HbA1C) levels. ATP-sensitive potassium channels in pancreatic beta cells play a role as essential metabolic sensors. When these channels are open, leading to K+ efflux from the cell, membrane hyperpolarization, and suppression of insulin secretion. Glimepiride inhibits the ATP-sensitive potassium channel by binding non-specifically to the B sites of both sulfonylurea receptor-1 (SUR1) and sulfonylurea receptor-2A (SUR2A) subunits as well as the A site of SUR1 subunit of the channel and blocks the influx of potassium ultimately promote insulin secretion from the beta cell.
Glimepiride is completely absorbed through GIT and the volume of distribution was 8.8 L (113 mL/kg). The plasma protein of glimepiride was 99.5% and is mainly metabolised in liver by family of CYP enzymes. It is mainly excreted in urine and the half-life is 5 to 8 hours.

Voglibose, an alpha-glucosidase inhibitor, is a synthetic compound with potent and enduring therapeutic efficacies against disorders of sensory, motor and autonomic nerve systems due to diabetes mellitus. The membrane-bound intestinal alpha-glucosidases hydrolyze oligosaccharides, trisaccharides, and disaccharides to glucose and other monosaccharides in the small intestine. Pancreatic alpha-amylase hydrolyzes complex starches to oligosaccharides in the lumen of the small intestine. Inhibition of these enzyme systems reduces the rate of digestion of complex carbohydrates. Less glucose is absorbed because the carbohydrates are not broken down into glucose molecules.
When administered orally it is slowly and poorly absorbed. It act mainly in intestine.

Pharmacokinetics

• Absorption: Glimepiride SR — gradual release; Metformin — absorbed mainly in small intestine; Voglibose — minimal systemic absorption, acts locally in gut
• Distribution: Glimepiride — highly protein bound; Metformin — not protein bound
• Metabolism: Glimepiride — hepatic metabolism; Metformin — not metabolized; Voglibose — minimal metabolism
• Elimination: Glimepiride — renal and biliary excretion; Metformin — excreted unchanged in urine; Voglibose — fecal excretion
• Half-life: Glimepiride ≈ 5–9 hours; Metformin ≈ 6 hours; Voglibose — short, local intestinal action

Side Effects

• Hypoglycemia (Glimepiride)
• Nausea
• Diarrhea
• Flatulence (Voglibose)
• Headache
• Rare: lactic acidosis, severe hypoglycemia

Contraindication

• Hypersensitivity to Glimepiride, Metformin, Voglibose, or excipients
• Renal impairment (eGFR < 30 mL/min/1.73m²)
• Hepatic impairment
• Alcoholism
• Conditions predisposing to lactic acidosis

Interaction

• Alcohol — increases risk of lactic acidosis with Metformin
• Beta-blockers — may mask hypoglycemia symptoms
• Cationic drugs (e.g., cimetidine) — compete for renal tubular secretion with Metformin
• Other antidiabetic agents — additive hypoglycemic effect

Warning and Precautions

• Monitor renal function before and during therapy
• Discontinue if lactic acidosis is suspected
• Use cautiously in elderly patients
• Monitor blood glucose regularly to avoid hypoglycemia
• Advise patients to avoid excessive alcohol intake
• Flatulence and GI discomfort may occur with Voglibose