Management of Polymyxin-Associated Acute Kidney Injury (AKI)

Introduction to Management Strategies

For patients with polymyxin-associated AKI, the American College of Critical Care Medicine recommends switching to polymyxin B from colistin, dose adjustment based on renal function, discontinuation of concurrent nephrotoxic agents, and close monitoring of renal parameters as management strategies 1

Preventive measures for polymyxin-associated AKI include avoiding concurrent use of other nephrotoxic medications when possible, and discontinuation of NSAIDs, which can exacerbate kidney injury 2, 3

AKI should be diagnosed when serum creatinine increases by ≥0.3 mg/dL within 48 hours or ≥50% from baseline, or when urine output is reduced below 0.5 mL/kg/h for >6 hours 2
Monitor for early signs of nephrotoxicity, including albuminuria 2, cellular casts 4, azotemia 4, and diminishing urine output 2

Immediately discontinue all potentially nephrotoxic medications 3
Consider switching from colistin to polymyxin B if the patient is on colistin, as polymyxin B has been associated with lower incidence of renal failure 1, 5, 4
Adjust polymyxin B dosing based on renal function, with a recommended loading dose of 2-2.5 mg/kg and maintenance dose of 1.5-3 mg/kg/day 1, 5, 4
For patients on continuous renal replacement therapy, dose adjustment is not necessary for polymyxin B, and a dose of at least 9 million IU/day is suggested for colistin 1, 5, 4
For patients on intermittent hemodialysis, administer 2 million IU colistimethate sodium every 12 hours with a normal loading dose, and schedule dialysis toward the end of a CMS dosage interval 1, 5, 4

Monitor renal function closely during polymyxin therapy, and assess urine output, vital signs, and fluid status as indicated 2, 3

If the patient has a concurrent infection requiring antibiotics, obtain cultures before starting therapy to guide definitive treatment 3
Avoid antibiotics with known nephrotoxic potential when alternatives are available for patients with suspected UTI and AKI 3
Do not treat asymptomatic bacteriuria in patients with AKI 3

Avoid the combination of NSAIDs, diuretics, and ACE inhibitors/ARBs during polymyxin treatment as this dramatically increases AKI risk 3