Metformin

Metformin (commonly marketed under brand names like Glucophage) is the foundational, first-line oral biguanide antihyperglycemic agent for treating type 2 diabetes mellitus. Unlike insulin secretagogues (e.g., sulfonylureas), metformin does not stimulate insulin secretion and therefore rarely causes hypoglycemia when used as monotherapy. Its primary mechanism involves activating AMP-activated protein kinase (AMPK), which leads to:

• Inhibition of Hepatic Gluconeogenesis: Reducing the liver’s production of glucose.

• Decreased Intestinal Absorption: Lowering glucose absorption in the gastrointestinal tract.

• Enhanced Peripheral Insulin Sensitivity: Increasing peripheral glucose uptake and utilization in skeletal muscle and adipose tissue.

Primary Medical Indications

Metformin is indicated for adult and pediatric populations (aged 10 years and older) across several endocrine and metabolic conditions:

• Type 2 Diabetes Mellitus: First-line pharmacotherapy (alongside diet and lifestyle modifications) to improve glycemic control in adults and children.

• Prediabetes Management: Off-label or approved indication to delay or prevent the onset of type 2 diabetes in high-risk individuals.

• Polycystic Ovary Syndrome (PCOS): Off-label use to manage insulin resistance, regulate menstrual cycles, and promote ovulation in women with PCOS.

• Antipsychotic-Induced Weight Gain: Off-label administration to mitigate weight gain associated with second-generation antipsychotics.

Key Product Specifications & Dosing Forms

Critical Safety Guidelines & Precautions

• Boxed Warning for Lactic Acidosis: Metformin can cause a rare but life-threatening build-up of lactic acid in the blood. Risk factors include renal impairment (eGFR less than 30 mL/min/1.73 $\text{m}^2$), severe liver disease, acute heart failure, excessive alcohol consumption, and sepsis.

• Iodinated Contrast Procedures: Metformin must be temporarily withheld prior to or at the time of intravascular iodinated contrast radiological procedures in patients with eGFR between 30 and 60 mL/min/1.73 $\text{m}^2$ or with a history of liver disease, alcoholism, or heart failure.

• Vitamin $B_{12}$ Deficiency: Long-term metformin therapy can impair intestinal absorption of vitamin $B_{12}$, potentially leading to anemia or peripheral neuropathy. Serum $B_{12}$ levels should be checked periodically.

• GI Tolerability: Nausea, vomiting, flatulence, and loose stools are common during treatment initiation; starting with low doses and slowly titrating upward—or switching to extended-release (XR) formulations—significantly improves tolerability.