tedizolid and Thrombocytopenia

Thrombocytopenia is commonly seen in patients receiving linezolid for >14 days. Linezolid is a reversible inhibitor of mitochondrial function in various cell types. This study investigated the inhibitory effects of linezolid and tedizolid, and their potential recovery on (i) CYTox I expression (subunit I of cytochrome c-oxidase; encoded by the mitochondrial genome), (ii) cytochrome c-oxidase activity and (iii) mitochondrial respiration (Seahorse bioanalysis) in two megakaryocytic cell lines [UT-7 WT (human acute megakaryoblastic leukaemia cells) and UT-7 MPL (transduced to express the thrombopoietin receptor)]. Cells were exposed to linezolid (0.5-25 mg/L) or tedizolid (0.1-5 mg/L) for up to 5 days and recovery followed after drug removal. Both oxazolidinones caused concentration- and time-dependent inhibition of CYTox I expression, cytochrome c-oxidase activity and mitochondrial spare capacity. On electron microscopy, mitochondria appeared dilated with a loss of cristae. Globally, tedizolid exerted stronger effects than linezolid. While CYTox I expression recovered completely after 6 days of drug washout, only partial (linezolid) or no (tedizolid) recovery of cytochrome c-oxidase activity, and no rescue of mitochondrial spare capacity (after 3 days) was observed. Thus, and in contrast to previous studies using a variety of cell lines unrelated to megakaryocytic lineages, the inhibitory effects exerted by oxazolidinones on the mitochondrial function of megakaryoblastic cells appear to be particularly protracted. Given the dynamics of platelet production and destruction, these results may explain why oxazolidinone-induced thrombocytopenia is one of the most common side effects in patients exposed to these antibiotics.

Topics: Cell Line; Electron Transport Complex IV; Humans; Linezolid; Megakaryocyte Progenitor Cells; Mitochondria; Oxazolidinones; Oxygen Consumption; Protein Synthesis Inhibitors; Tetrazoles; Thrombocytopenia

Several studies have suggested the risk of thrombocytopenia with tedizolid, a second-in-class oxazolidinone antibiotic (approved June 2014), is less than that observed with linezolid (first-in-class oxazolidinone). Using data from the Food and Drug Administration adverse event reporting system (July 2014 through December 2016), we observed significantly increased risks of thrombocytopenia of similar magnitudes with both antibiotics: linezolid reporting odds ratio [ROR], 37.9 (95% confidence interval [CI], 20.78 to 69.17); tedizolid ROR, 34.0 (95% CI, 4.67 to 247.30).

Topics: Anti-Bacterial Agents; Humans; Linezolid; Oxazolidinones; Tetrazoles; Thrombocytopenia