Question

Metformin is contraindicated in the patient with a GFR <45 mL/min/1.73 m2 because of the risk of:

a) Hypokalemia.
b) Worsening renal function.
c) Hypocalcemia.
d) Lactic acidosis.

Answer 1

Metformin is contraindicated in patients with a GFR < 45 mL/min/1.73 m² due to the risk of lactic acidosis, a condition that occurs when metformin accumulates in the body leading to a potentially fatal build-up of lactic acid, exacerbated by chronic kidney disease.

Step-by-step explanation:

Metformin is contraindicated in patients with a Glomerular Filtration Rate (GFR) of less than 45 mL/min/1.73 m2 primarily due to the risk of lactic acidosis. Metformin can result in the accumulation of lactate in the body when renal function is impaired, as the kidneys are responsible for metformin excretion. Reduced renal clearance of metformin increases the risk for lactic acid build-up, which can be potentially fatal.

This condition is particularly hazardous for patients with chronic kidney disease (CKD) as they already have a compromised ability to clear metabolic acids from the body, exacerbating the risk for metabolic acidosis. Additionally, the contemporary acidogenic diet in patients with chronic kidney disease can further contribute to the risk of insulin resistance and cardiovascular disease.