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Difficulty: MediumMonitoring and Treatment Evaluation

A 62-year-old man with a 12-year history of type 2 diabetes mellitus and chronic kidney disease is evaluated during a routine follow-up visit. One month ago, his hemoglobin A1c was 8.1% and his estimated glomerular filtration rate (eGFR) was 45 mL/min/1.73 m 2^2. At that time, dapagliflozin was added to his medication regimen, which also includes metformin and lisinopril, to optimize glycemic control and slow the progression of diabetic nephropathy. Today, the patient reports feeling well overall. He denies urinary frequency, dysuria, dizziness, or orthopnea. He mentions having mild, intermittent bilateral knee pain due to osteoarthritis and asks for a medication recommendation. His blood pressure is 126/78 mm Hg and heart rate is 74/min.

Laboratory studies obtained today show:

TestResult
Serum sodium138 mEq/L
Serum potassium4.6 mEq/L
Serum urea nitrogen24 mg/dL
Serum creatinine1.8 mg/dL (Baseline 1.5 mg/dL)
eGFR37 mL/min/1.73 m2^2

Which of the following is the most appropriate next step in the management of this patient?

  1. Continue the current regimen and recommend oral acetaminophen for the knee painAnswer
  2. B
    Discontinue dapagliflozin to prevent progressive acute kidney injury
  3. C
    Discontinue lisinopril due to the synergistic risk of glomerular ischemia
  4. D
    Order a renal ultrasound with Doppler to evaluate for renal artery stenosis
  5. E
    Continue the current regimen and prescribe oral naproxen for the knee pain

Answer

The most appropriate next step is to continue the current medication regimen without modifications and recommend oral acetaminophen for the patient's knee osteoarthritis pain.
The correct answer is to continue the current regimen and recommend oral acetaminophen for the knee pain. This patient has experienced a 20% increase in serum creatinine (from 1.5 mg/dL to 1.8 mg/dL) one month after initiating dapagliflozin, an SGLT2 inhibitor. SGLT2 inhibitors cause afferent arteriolar vasoconstriction by increasing sodium delivery to the macula densa, which lowers intraglomerular pressure. This hemodynamic change is the mechanism behind their long-term renoprotective effect, but it causes an expected, mild initial drop in eGFR. Current clinical guidelines state that an initial serum creatinine increase of up to 30% from baseline is acceptable and should not prompt discontinuation of the drug. Furthermore, the patient's osteoarthritis should be managed with acetaminophen. Oral NSAIDs (like naproxen) are contraindicated in patients with chronic kidney disease, as they inhibit prostaglandin-mediated afferent arteriolar vasodilation, increasing the risk of severe acute kidney injury, particularly in patients taking ACE inhibitors.

Step-by-Step Solution

1
Analyze the patient's change in renal function after initiating the SGLT2 inhibitor.
The serum creatinine increased from 1.5 mg/dL to 1.8 mg/dL, representing exactly a 20% increase.
To determine if the laboratory change falls within the acceptable safety threshold for this class of medications.
2
Evaluate the clinical guidelines for SGLT2 inhibitor monitoring.
An initial increase in serum creatinine of up to 30% is an expected, hemodynamically mediated effect that correlates with long-term renoprotection. The medication should be continued.
To make the correct evidence-based clinical decision regarding the continuation or discontinuation of the new medication.
3
Assess the patient's request for osteoarthritis pain medication in the context of his comorbidities.
The patient has chronic kidney disease and is taking an ACE inhibitor. NSAIDs are contraindicated due to the risk of precipitating acute kidney injury.
To select an analgesic (acetaminophen) that provides safe symptom management without exacerbating renal impairment.

Key Concept

An initial increase in serum creatinine of up to 30% is an expected hemodynamic effect of SGLT2 inhibitors and does not warrant discontinuation. Oral NSAIDs are contraindicated in patients with CKD taking ACE inhibitors.
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Topics

Monitoring and Treatment Evaluation

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