Monitoring and evaluation of colistin blood level at intensive care units

To evaluate the influence of the parameters predicted to develop nephrotoxiciy and the incidence of acute renal failure on the development of nephrotoxicity 30 patients who underwent intravenous colistin therapy for at least 3 days between 26 April 2017 and 18 October 2017 in medical intensive care units of Hacettepe University Hospitals were included in this prospective study. After the third day of colistin therapy, the blood samples of 5 mL from each patient were drawn 10 minutes before colistin administration (trough level) and 30 minutes after the end of infusion (peak level). Samples were centrifuged and stored at -80 °C until analyzed. Concentrations were determined by liquid chromatography tandem mass spectrometry. On day 7, the mean±sd plasma trough and peak concentrations of patients with nephrotoxicity were 14.50±7.23 mg/L and 45.30±21.04 μg/mL, respectively and they were respectively 17.27±2.84 mg/L and 52.33±27.70 mg/L in patients without nephrotoxicity (p>0.05). Although nephrotoxicity was determined with colistin usage (after 7 days 33%, at the end of treatment 40%), the influence of trough and peak levels were not statistically significant on the development of nephrotoxicity (respectively p=0.483; p=0.695). It was found that daily (227±67.17 mg; p=0.564) and cumulative colistin doses (1590±600.833 mg; p=0.682) were higher in patients with nephrotoxicity, although this was not statistically significant. Eventhough the influence of factors on colistin toxicity was not detected in this study, in terms of colistin resistance and toxicity, rational use of colistin should be considered.