SHALINA METFORMIN

Indications

• Type 2 diabetes mellitus
• Polycystic ovary syndrome (PCOS)
• Weight management in diabetic patients

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Metformin primarily works by decreasing hepatic glucose production, particularly by reducing gluconeogenesis in the liver. It also enhances insulin sensitivity in peripheral tissues, particularly muscle, which leads to improved glucose uptake and utilization. Furthermore, metformin slows intestinal absorption of glucose.

Pharmacodynamics

Metformin does not stimulate insulin secretion from the pancreas, hence it does not cause hypoglycemia when used alone. The drug may also have favorable effects on lipid profiles and may reduce the risk of macrovascular complications related to diabetes.

Pharmacokinetics

Metformin is absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 2 to 3 hours after administration. It has a bioavailability of about 50-60% after oral doses. The drug is not metabolized and is excreted unchanged in the urine. It has a half-life of about 6.2 hours, and its effects can last beyond this due to the gradual release from tissues.

Contra-indications

• Severe renal impairment
• Acute or chronic metabolic acidosis
• Diabetic ketoacidosis
• Hypersensitivity to metformin or any excipients

Adverse effects

• Gastrointestinal disturbances (nausea, vomiting, diarrhea, abdominal pain)
• Lactic acidosis (rare but serious)
• Vitamin B12 deficiency
• Skin reactions (rash, pruritus)

Interactions

• Alcohol (increases risk of lactic acidosis)
• Cationic drugs (may affect renal clearance)
• Iodinated contrast media (risk of lactic acidosis and acute renal failure)

Precautions

• Monitor renal function regularly
• Use with caution in patients with hepatic impairment
• Discontinue prior to surgical procedures or during acute illness
• Ensure adequate hydration to reduce risk of lactic acidosis

Pregnancy

Metformin is not recommended during pregnancy unless the potential benefit justifies the potential risk to the fetus. It is preferred to use insulin for glycemic control.

Breast-feeding

Metformin is excreted in breast milk in small amounts. It is considered safe to use during breastfeeding.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets
• Extended-release tablets
• Oral solution