Which is a common side-effect of metformin?

Which is a common side-effect of metformin?

• A. Lactic acidosis
• B. Hypoglycemia
• C. Weight gain
• D. Pancreatitis

Answer: (A)

Metformin’s most important adverse effect to remember is the potential for lactic acidosis. This drug can interfere with mitochondrial respiration and hepatic lactate clearance, so in settings where tissue perfusion is reduced or kidney function is impaired, lactate can accumulate. That’s why lactic acidosis is highlighted: it’s a serious, life‑threatening complication that clinicians watch for, especially in patients with renal impairment, dehydration, or conditions causing hypoxia. The other options don’t fit as well with metformin: hypoglycemia is uncommon because metformin doesn’t increase insulin secretion; weight gain is not typical (in fact, metformin often causes weight loss or neutrality); pancreatitis isn’t a recognized common adverse effect. So, while lactic acidosis is rare in healthy patients, it remains the most important, exam‑relevant adverse effect to associate with metformin.

Metformin’s most important adverse effect to remember is the potential for lactic acidosis. This drug can interfere with mitochondrial respiration and hepatic lactate clearance, so in settings where tissue perfusion is reduced or kidney function is impaired, lactate can accumulate. That’s why lactic acidosis is highlighted: it’s a serious, life‑threatening complication that clinicians watch for, especially in patients with renal impairment, dehydration, or conditions causing hypoxia. The other options don’t fit as well with metformin: hypoglycemia is uncommon because metformin doesn’t increase insulin secretion; weight gain is not typical (in fact, metformin often causes weight loss or neutrality); pancreatitis isn’t a recognized common adverse effect. So, while lactic acidosis is rare in healthy patients, it remains the most important, exam‑relevant adverse effect to associate with metformin.