Examkin

Question

Difficulty: MediumMonitoring and Treatment Evaluation

A 6464-year-old man with a history of type 2 diabetes mellitus, hypertension, and hyperlipidemia is evaluated in the outpatient clinic for a routine follow-up. He feels well and reports no new symptoms, including no changes in urine output or peripheral edema. His current medications include metformin 1000 mg1000\text{ mg} twice daily, empagliflozin 10 mg10\text{ mg} daily, lisinopril 20 mg20\text{ mg} daily, and atorvastatin 40 mg40\text{ mg} daily. Vital signs show a blood pressure of 130/80 mmHg130/80\text{ mmHg} and a heart rate of 72/min72/\text{min}. Physical examination is unremarkable.

Laboratory results from the current and previous visits are shown below:

Parameter12 Months Ago6 Months AgoCurrent Visit
Hemoglobin A1c8.2%8.2\%7.5%7.5\%7.3%7.3\%
Serum creatinine1.6 mg/dL1.6\text{ mg/dL}1.8 mg/dL1.8\text{ mg/dL}2.5 mg/dL2.5\text{ mg/dL}
Estimated GFR45 mL/min/1.73 m245\text{ mL/min/1.73 m}^240 mL/min/1.73 m240\text{ mL/min/1.73 m}^226 mL/min/1.73 m226\text{ mL/min/1.73 m}^2
Serum potassium4.3 mEq/L4.3\text{ mEq/L}4.6 mEq/L4.6\text{ mEq/L}4.9 mEq/L4.9\text{ mEq/L}
Urine albumin-to-creatinine ratio380 mg/g380\text{ mg/g}340 mg/g340\text{ mg/g}290 mg/g290\text{ mg/g}

Based on these findings, which of the following is the most appropriate next step in management?

  1. Discontinue metforminAnswer
  2. B
    Discontinue empagliflozin
  3. C
    Discontinue lisinopril
  4. D
    Order a renal ultrasound
  5. E
    Refer for arteriovenous fistula creation

Answer

The most appropriate next step is to discontinue metformin.
The correct action is to discontinue metformin. Metformin is primarily renally excreted, and its accumulation in severe chronic kidney disease significantly increases the risk of metformin-associated lactic acidosis. Current prescribing guidelines mandate that metformin must be permanently discontinued when a patient's estimated glomerular filtration rate (eGFR) falls below 30 mL/min/1.73 m230\text{ mL/min/1.73 m}^2. Because this patient's eGFR has dropped to 26 mL/min/1.73 m226\text{ mL/min/1.73 m}^2 (CKD stage 4), removing this medication is the most urgent and appropriate next step.

Step-by-Step Solution

1
Analyze the patient's laboratory trends over the past year.
The patient's estimated glomerular filtration rate (eGFR) has progressively declined from 4545 to 26 mL/min/1.73 m226\text{ mL/min/1.73 m}^2, placing him in chronic kidney disease (CKD) stage 4.
Tracking longitudinal kidney function is essential to adjust renally cleared medications and prevent toxicity.
2
Evaluate the safety profile of the patient's current medications at an eGFR of 26 mL/min/1.73 m226\text{ mL/min/1.73 m}^2.
Metformin requires discontinuation, while empagliflozin and lisinopril can safely be continued to provide ongoing nephroprotection.
Various medications have strict eGFR cutoffs for dosing or absolute contraindications to avoid severe adverse events.
3
Identify the critical required intervention.
Metformin must be stopped immediately.
Metformin accumulation in severe CKD significantly increases the risk of life-threatening lactic acidosis.

Key Concept

Metformin must be permanently discontinued when the estimated glomerular filtration rate (eGFR) falls below 30 mL/min/1.73 m230\text{ mL/min/1.73 m}^2 to prevent lactic acidosis.
Estimated Time:1m 30s
Rate this question

Topics

Monitoring and Treatment Evaluation

More questions from this topic