How to manage a patient with impaired renal function and a GFR of 46?

From the Guidelines

Managing a patient with impaired renal function and a GFR of 46 requires careful medication adjustment and monitoring, with a focus on blood pressure control, preferably using ACE inhibitors or ARBs, and lifestyle modifications to slow CKD progression. This patient has Stage 3a chronic kidney disease (CKD), requiring dose adjustments for renally cleared medications. Common medications needing adjustment include metformin (limit to 1000 mg daily), gabapentin (reduce dose by 50%), and many antibiotics like levofloxacin (750 mg every 48 hours instead of daily) 1. NSAIDs should be avoided due to their potential to worsen kidney function.

Key Considerations

• Blood pressure control is essential, with a target below 130/80 mmHg, as recommended by the European Society of Hypertension and the European Society of Cardiology 1.
• Regular monitoring should include quarterly kidney function tests, annual urinary albumin-to-creatinine ratio, and electrolyte panels.
• Lifestyle modifications are crucial, including:
  • Sodium restriction to 2-3 g daily
  • Moderate protein intake (0.8 g/kg/day) 1
  • Adequate hydration
  • Smoking cessation These interventions help slow CKD progression by reducing hyperfiltration stress on remaining nephrons and minimizing additional kidney damage from medications and comorbidities.

Medication Adjustments

• ACE inhibitors or ARBs like lisinopril (start at 5-10 mg daily) or losartan (25-50 mg daily) are recommended for blood pressure control and to reduce proteinuria 1.
• Other medications may need to be adjusted or avoided based on the patient's individual needs and kidney function.

Additional Recommendations

• Patients with CKD should be referred to a specialist for consultation and comanagement if the patient's personal physician cannot adequately evaluate and treat the patient, particularly if the GFR is less than 30 mL/min per 1.73 m² 1.
• Dietary interventions, such as reducing salt intake and avoiding high protein intake, may assist in slowing the progression of CKD 1.

From the FDA Drug Label

1. 3 Impaired Renal Function Monitor renal function periodically in patients treated with lisinopril. Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, post-myocardial infarction or volume depletion) may be at particular risk of developing acute renal failure on lisinopril. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on lisinopril [see Adverse Reactions (6. 1), Drug Interactions (7.4)].

Management of a patient with impaired renal function and a GFR of 46:

• Monitor renal function periodically while the patient is being treated with lisinopril.
• Be aware of the risk of acute renal failure, especially since the patient's GFR is already impaired.
• Consider the patient's overall clinical condition, including any other health issues that may affect renal function, such as renal artery stenosis, chronic kidney disease, or severe congestive heart failure.
• Adjust the treatment plan as needed to minimize the risk of further decreasing renal function, which may include withholding or discontinuing lisinopril if a clinically significant decrease in renal function occurs 2.
• Note that the elimination half-life of lisinopril is little changed when the glomerular filtration rate is above 30 mL/min 2.

From the Research

Patient Management with Impaired Renal Function

The patient's GFR of 46 indicates impaired renal function. To manage this patient, the following points should be considered:

• The patient's GFR has increased from 42 two months ago, which may indicate a positive response to treatment or other factors.
• Blood urea nitrogen (BUN) and creatinine levels should be monitored regularly to assess renal function.

Treatment Options

The following treatment options may be considered:

• Angiotensin-converting enzyme (ACE) inhibitors, which have been shown to increase GFR and renal blood flow in patients with hypertension, and may also have a beneficial effect on limiting the progression of renal disease 3, 4.
• Calcium entry blockers, which may also exert a beneficial effect on renal function, although the evidence is less clear 3.
• Other antihypertensive agents, which may be used in combination with ACE inhibitors or calcium entry blockers to control blood pressure and reduce proteinuria.

Monitoring and Follow-up

Regular monitoring of the patient's renal function, including GFR, BUN, and creatinine levels, is essential to assess the effectiveness of treatment and adjust the treatment plan as needed.

• The patient's renal function should be monitored closely, especially when initiating or adjusting antihypertensive therapy, to avoid acute deterioration in renal function 3, 5.
• A decline in renal function has been associated with an increased risk of heart failure readmissions, highlighting the importance of optimizing renal function in patients with heart failure 6.

Additional Considerations

The following additional considerations may be relevant:

• The use of ACE inhibitors has been shown to reduce proteinuria in patients with chronic glomerulonephritis, although the effect on renal haemodynamics may be variable 7.
• The patient's overall cardiovascular risk should be assessed, and treatment should be tailored to address any underlying cardiovascular conditions.