Nephrotoxicity is a great concern in patients receiving intravenous colistin and there is a disparity in the reported rates between previous studies. Several preclinical researches studied the effect of the antioxidants (e.g. L.carnitine, vitamin C, vitamin E, N-acetyl cysteine, and alpha lipoic acid) in reducing the risk of colistin-induced nephrotoxicity but there is a lack of clinical studies on human. Due to the paucity of studies that early predict colistin-induced nephrotoxicity using early acute kidney injury "AKI" biomarkers e.g. kidney injury molecule 1"KIM1" and the lack of human studies that evaluate the role of alpha lipoic acid in ameliorating colistin-induced nephrotoxicity, so this study will be conducted.