What are the management and treatment options for a patient with impaired renal function?

Management of Severe Renal Impairment (GFR 20.7 mL/min/1.73 m²)

This patient has Stage 4 chronic kidney disease approaching Stage 5 (end-stage renal disease) and requires immediate nephrology referral, careful medication review with dose adjustments or discontinuation of renally-cleared drugs, and preparation for renal replacement therapy. 1, 2

Immediate Actions

Nephrology Referral

• Patients with GFR <30 mL/min/1.73 m² should be referred to a nephrologist immediately for specialized management and preparation for potential dialysis or transplantation 1
• This patient is at Stage 4 CKD (GFR 15-29 mL/min/1.73 m²) and requires evaluation of benefits, risks, and timing of kidney replacement therapy 1

Medication Management Priority

• Estimate creatinine clearance and adjust all renally-cleared medications immediately to prevent drug accumulation and toxicity 1, 3
• Discontinue metformin immediately if the patient is taking it - metformin is contraindicated with eGFR <30 mL/min/1.73 m² due to high risk of fatal lactic acidosis 3
• Review all medications for nephrotoxic agents (NSAIDs, aminoglycosides, contrast agents) and discontinue them 1, 2

Specific Medication Considerations

Contraindicated Medications

• Metformin must not be initiated and should be stopped in patients with eGFR <30 mL/min/1.73 m² 3
• Avoid sofosbuvir-based hepatitis C regimens as they are primarily renally eliminated 2

Medications Requiring Dose Adjustment

• Zoledronic acid should be held when creatinine clearance is <30 mL/min 1
• Lenalidomide requires significant dose reduction in multiple myeloma patients with severe renal impairment 1
• Most renally-cleared medications need adjustment based on pharmacokinetic data 1

Safe Medication Options

• Bortezomib-containing regimens can be used without dose adjustment in severe renal impairment and dialysis 1
• Denosumab may be administered without dose adjustment but requires careful monitoring for severe hypocalcemia 1, 2
• Glecaprevir/pibrentasvir for hepatitis C requires no dose adjustment in CKD stage 4-5 1

Preparation for Renal Replacement Therapy

Patient Education

• Begin education about treatment options immediately - patients at Stage 4 CKD need time to understand dialysis, transplantation, and conservative management options 1
• Discuss hemodialysis, peritoneal dialysis, kidney transplantation, and conservative therapy without dialysis 1

Access Planning

• Plan for permanent vascular access (arteriovenous fistula) or peritoneal dialysis catheter placement before dialysis becomes urgent 1
• Evaluate candidacy for preemptive kidney transplantation if appropriate 1, 2

Timing Considerations

• Dialysis initiation should be considered when patients develop uremic symptoms, fluid overload refractory to diuretics, severe metabolic acidosis, or hyperkalemia 1
• Conservative therapy with dietary management, loop diuretics, and sodium polystyrene sulfonate is appropriate for selected patients who decline dialysis 1

Monitoring and Supportive Care

Laboratory Monitoring

• Monitor serum creatinine, BUN, electrolytes (especially potassium and calcium), and acid-base status frequently 1
• Check vitamin B12 levels if patient has been on metformin, as deficiency is common 3
• Assess for anemia and consider erythropoiesis-stimulating agents if indicated 1

Metabolic Management

• Correct hypercalcemia if present with hydration and bisphosphonates (dose-adjusted) or denosumab 1
• Manage hyperkalemia with dietary restriction and sodium polystyrene sulfonate 1
• Address metabolic acidosis with sodium bicarbonate if indicated 1

Cardiovascular Risk Reduction

• Control blood pressure aggressively - target <130/80 mmHg using ACE inhibitors or ARBs if proteinuria is present 1
• Monitor for volume overload and adjust diuretic therapy accordingly 1
• This patient has significantly elevated cardiovascular mortality risk due to severe CKD 1

Special Clinical Scenarios

If Contrast Imaging Required

• Provide adequate hydration before and after any contrast procedures 1
• Use minimum contrast volume necessary 1
• Consider alternative imaging modalities when possible 1

If Acute Deterioration Occurs

• Evaluate for reversible causes: volume depletion, nephrotoxic medications, urinary obstruction, or acute interstitial nephritis 1
• Urgent dialysis may be required for severe hyperkalemia, pulmonary edema, uremic pericarditis, or severe metabolic acidosis 1

Common Pitfalls to Avoid

• Do not rely on serum creatinine alone - it overestimates GFR in patients with low muscle mass and underestimates severity of renal dysfunction 1, 4, 5
• Do not delay nephrology referral - waiting until GFR <15 mL/min/1.73 m² results in suboptimal access placement and emergency dialysis initiation 1
• Do not continue nephrotoxic medications including NSAIDs, which can precipitate acute-on-chronic kidney injury 1, 2
• Do not assume normal troponin levels exclude cardiac disease - troponin T is frequently elevated in renal failure without acute coronary syndrome 1