If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 1 exam, you might want to know which questions are most often missed by test-prep takers. Check out this example from Kaplan Medical, and read an expert explanation of the answer. Also check out all posts in this series.
A 63-year-old woman with type 2 diabetes mellitus comes to the physician for a follow-up examination. She states that she has attempted diet control and exercise for the last nine months. She has a history of heart failure, hypertension and hypercholesterolemia.
She currently takes enalapril and low-dose aspirin and has no drug allergies. Laboratory studies show a creatinine of 2.2 mg/dL and a hemoglobin A1c of 8.9%.
Which of the following is the most appropriate initial pharmacotherapy for this patient?
A. Glimepiride.
B. Metformin.
C. Metformin and glipizide.
D. Pramlintide.
E. Rosiglitazone.
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The correct answer is A.
Kaplan Medical explains why
Kaplan Medical explains why
The initial decision about the choice of drug to manage hyperglycemia must take into account the comorbidities of the patient and the relative contraindications of the drug. Insulin secretagogues such as sulfonylureas (glipizide, glyburide, glimepiride), α-glucosidase inhibitors (miglitol, acarbose), thiazolidinediones ("glitazones") (pioglitazone, rosiglitazone), biguanides (metformin), and insulin all are approved for monotherapy for diabetes.
Most patients are initially started on metformin unless there is a contraindication, such as renal dysfunction (as seen in this patient). Sulfonylureas, DPP-4 inhibitors (sitagliptin), GLP-1 agonists (exenatide) or glitazones (rosiglitazone) are generally used as second line agents when metformin is unsuccessful or cannot be used. In this patient, the most recommended initial treatment would be the sulfonylurea glimepiride.
Why the other answers are wrong
Why the other answers are wrong
Choices B and C: Metformin, a biguanide, has a rare but serious complication of lactic acidosis. Despite this risk, it is the drug of choice for type 2 diabetes. A primary reason to use another agent in place of metformin is when the patient is at risk for developing metformin-induced lactic acidosis.
