Question

Lactic acidosis is more likely to be caused by which one of the following drugs?

• A. Gliclazide
• B. Acarbose
• C. Metformin
• D. Pioglitazone

Hint:

Think about which antidiabetic drug changes how cells make energy and raises lactate.

Answer 1

The Correct Option is C

Step 1: Understanding the Question.
The question asks which drug used for diabetes is most linked to lactic acidosis, a dangerous buildup of lactic acid in the blood.

Step 2: Key Concept.
Metformin is a biguanide. It works by cutting down glucose production in the liver and by pushing muscle cells to use glucose without oxygen. This anaerobic path makes more lactate. In patients with poor kidney function, metformin builds up in the blood and lactate keeps rising, which can tip into lactic acidosis.

Step 3: Detailed Explanation.
Gliclazide is a sulfonylurea. It pushes the pancreas to release more insulin. Its main risk is low blood sugar, not lactic acidosis.
Acarbose blocks the gut enzyme alpha glucosidase, so starches break down slower. It causes gas and bloating, not lactic acidosis.
Metformin blocks liver glucose output and raises lactate production, so when it builds up, as in kidney failure, it causes lactic acidosis. This is its best known serious side effect.
Pioglitazone works on PPAR gamma receptors. It causes fluid retention, weight gain, and can harm the liver, but it does not cause lactic acidosis.

Step 4: Final Answer.
Metformin is the drug most likely to cause lactic acidosis.