Parenteral polymyxins: assessing efficacy and safety in critically ill patients with renal dysfunction

Studies have established the effectiveness and safety of polymyxins in treating multidrug resistant (MDR) pathogens. However, the challenge is whether these nephrotoxic drugs can be administered in compromised renal states. The present study was undertaken to establish their role in such patients. The effectiveness and nephrotoxicity of polymyxins in critically ill-patients harboring MDR Gram-negative bacteria with already compromised renal functions was compared with those with normal renal functions.

This retrospective cohort study (March 2008-March 2010) was conducted in the intensive care unit of a tertiary care hospital. A total of 48 eligible critically ill-patients receiving polymyxins were enrolled. A comparison was carried out (length of stay in hospital, mortality, renal function) between patients with acute kidney injury (AKI, n = 18; defined by the RIFLE classification) and patients with normal renal function (non-AKI, n = 30).

Patients with baseline AKI had a significantly higher adjusted mortality rate at admission when compared with the non-AKI group. At the end of therapy with polymyxins, 26.66% non-AKI patients developed renal dysfunction while 38.88% of patients in the AKI group had worsening of renal function (P = 0.006). However, there was no significant difference in the length of hospital stay (23.9 ± 13.24 vs. 30.5 ± 22.50; P = 0.406) and overall mortality (44.4% vs. 36.7%; P = 0.76) between two groups.

Polymyxins can be administered in AKI patients with favorable results provided used judiciously with strict monitoring of renal functions, dose modification according to creatinine clearance and aggressive fluid management.