Colistin co-administration with other nephrotoxins: experience of teaching hospital of Latvia

Background Colistin is a potentially nephrotoxic antibiotic used for the management of multidrug-resistant bacterial infections in critically ill patients. Co-administration with other nephrotoxins was reported as a potentially modifiable risk factor of colistin acute kidney injury. Objective To establish the role of colistin dosing and co-medications in development of colistin kidney injury. Setting Community teaching hospital in Latvia. Method Adult patients from intensive care units with diagnosed Gram-negative bacterial infections, undergoing colistin treatment for longer than 72 h, and not receiving renal replacement therapy were included in this retrospective study. Main outcome measure Colistin nephrotoxicity was defined as an increase in the serum creatinine level by at least 50% from the baseline after ≥ 48 h. Results In 73 of 87 cases, Acinetobacter baumannii pneumonia was diagnosed. The nephrotoxicity rate was 27.6% with a median onset of 8 days. In 79% of the cases, colistin was co-administrated with at least one potentially nephrotoxic agent. The most used nephrotoxins were loop diuretics (44 cases), non-steroidal anti-inflammatory drugs (19 cases) and vancomycin (11 cases). The use of nephrotoxins was similar in patients with colistin nephrotoxicity (group-1) and without it (group-2). Carbapenems were more common in group-2 (37% vs 62%, p = 0.004) and a colistin loading dose of 9 MU in group-1 (87% vs 62%, p = 0.027). However, in the multifactor regression analysis, the protective role of carbapenems was not confirmed. Conclusion Potentially nephrotoxic agents are commonly co-administrated with colistin. This study failed to prove their role in the development of acute kidney injury.

Colistin Use in Patients with Extreme Renal Function: From Dialysis to Augmented Clearance

Background and objectives: Colistin is used for the treatment of multidrug-resistant (MDR) Gram-negative bacteria infection in critically ill patients. It is recommended to adjust the dose in cases of renal impairment but not in cases of augmented renal clearance (ARC). The aim of this study was to determine colistin use pattern in patients with different renal functional states. Materials and Methods: Adult patients admitted to intensive care units of single Latvian hospitals in the years 2015–2017 with an MDR Gram-negative bacterial infection and at least 72 h colistin therapy were included in this study. Data were collected retrospectively from medical notes. Colistin use pattern and outcomes were analyzed in patients with different renal function prior to colistin therapy: normal, ARC, impaired, and on renal replacement therapy (RRT). Results: 100 cases of colistin use met the inclusion criteria. The study group was heterogeneous, and patients had different renal function states prior to colistin therapy-from continuous RRT (18 cases) to ARC (16 cases). The standard colistin dose of 9 million units (MU) daily was the most common dose among the patients. In many cases (43%), colistin dose adjustment did not follow the recent recommendations of drug manufacturers-this was mainly in patients with renal impairment prior to colistin therapy. Eighteen cases of colistin acute kidney injury (AKI) were detected, mostly (10 cases) in patients with normal renal function and without ARC prior to colistin therapy. No patients with colistin AKI needed RRT. Conclusions: Colistin doses varied greatly among patients, and in patients with renal function impairment it was commonly not in accordance with the summary of product characteristics (SPC). Patients with ARC mostly received a standard colistin daily dose of 9 MU daily, but the cumulative dose had a tendency to be higher and duration of colistin therapy was longer in comparison with other patient groups. ARC’s role in the development of colistin nephrotoxicity is still unclear.