The recommendations in this guideline were developed following a review of studies published before December 31, 2018, in English. Studies were identified through Library of Congress, LISTA (Library, Information Science & Technology Abstracts [EBSCO]), and PubMed database searches with no date restrictions using Medical Subject Headings. Examples of keywords used to conduct literature searches were polymyxin, colistin, polymyxin B, nephrotoxicity, pharmacokinetics, pharmacodynamics, area under the curve, toxicodynamics, resistance, carbapenem, A. baumannii, P. aeruginosa, and Klebsiella pneumoniae.