A 51-year-old woman comes to the physician because of several-month history of fatigue and increased thirst. She has no history of serious medical illness and takes no medications. She is 163 cm (5 ft 4 in) tall and weighs 72 kg (160 lb); BMI is 28 kg/m2. Physical examination shows no abnormalities. Hemoglobin A1c is 8.5% and fasting plasma glucose level is 196 mg/dL. Recommendations for dietary modification and exercise are provided, and pharmacotherapy with metformin is planned. Which of the following laboratory tests should be obtained prior to starting this medication?

Question

A 51-year-old woman comes to the physician because of several-month history of fatigue and increased thirst. She has no history of serious medical illness and takes no medications. She is 163 cm (5 ft 4 in) tall and weighs 72 kg (160 lb); BMI is 28 kg/m2. Physical examination shows no abnormalities.  Hemoglobin A1c is 8.5% and fasting plasma glucose level is 196 mg/dL.  Recommendations for dietary modification and exercise are provided, and pharmacotherapy with metformin is planned.  Which of the following laboratory tests should be obtained prior to starting this medication?

Quizplus · Accepted Answer

Eductional Objective: Metformin inhibits hepatic gluconeogenesis and increases peripheral glucose utilization.  Lactic acidosis is a rare complication of metformin therapy, but its risk is increased in patients with underlying renal insufficiency.

A 51-Year-Old Woman Comes to the Physician Because of Several-Month