Understanding Metformin: Mechanism of Action, Clinical Uses, and Safety Profile

Infographic Overview

Metformin is one of the most widely prescribed oral antidiabetic drugs globally. Known for its efficacy and safety, it plays a central role in managing Type 2 Diabetes Mellitus. In this post, we’ll explore its pharmacological mechanism, clinical applications, and safety considerations.

1. Mechanism of Action

Metformin primarily acts by reducing hepatic glucose production (gluconeogenesis). It enhances insulin sensitivity and increases peripheral glucose uptake. Unlike sulfonylureas, it does not stimulate insulin secretion, which reduces the risk of hypoglycemia.

• Activates AMP-activated protein kinase (AMPK)
• Decreases intestinal absorption of glucose
• Improves insulin receptor activity

2. Clinical Uses

Metformin is the first-line therapy for:

• Type 2 Diabetes Mellitus
• Polycystic Ovary Syndrome (PCOS)
• Insulin resistance in obese patients

It is often used in combination with other antidiabetic agents like sulfonylureas, DPP-4 inhibitors, or SGLT2 inhibitors.

3. Dosage and Administration

• Initial dose: 500 mg once or twice daily
• Maximum dose: 2000–2500 mg/day
• Extended-release formulations improve GI tolerance

4. Side Effects and Safety Profile

Common side effects include:

• Gastrointestinal discomfort (nausea, diarrhea)
• Metallic taste
• Vitamin B12 deficiency (long-term use)

Rare but serious: Lactic acidosis, especially in renal impairment or elderly patients.

5. Pharmacokinetics

• Absorption: ~50–60% bioavailability
• Half-life: ~6 hours
• Excretion: Renal (unchanged drug)

6. Clinical Considerations

• Contraindicated in renal failure (eGFR <30 mL/min)
• Should be withheld before contrast imaging
• Safe in pregnancy (Category B)

Conclusion

Metformin remains a cornerstone in diabetes management due to its effectiveness, safety, and affordability. Understanding its mechanism and clinical profile is essential for pharma students, healthcare professionals, and researchers.