Characterization of Vancomycin Reactions and Linezolid Utilization in the Pediatric Population

Background Red man syndrome (RMS) occurs because of non–IgE-mediated histamine release. Unlike vancomycin allergy, which necessitates the use of an alternative drug (often linezolid), RMS does not typically preclude further vancomycin use. Care should be taken to differentiate these reaction types from one another to prevent unnecessary vancomycin avoidance. Objective To characterize vancomycin reaction types in our population, and to determine whether having a reaction consistent with RMS is associated with otherwise unexplained vancomycin avoidance and linezolid use. Methods We retrospectively reviewed charts for children with documented vancomycin reactions. We classified the in-hospital reactions via an objective analysis and estimated the prevalence of different reaction types. We then identified children who received linezolid over 3 years, and investigated reasons for linezolid use instead of vancomycin. Results Of the 78 in-hospital reactions we characterized, 72 (92%) were objectively consistent with RMS, 5 we could not objectively classify (2 most likely RMS, 3 more suspicious for possible IgE-mediated allergy), and 1 was a non-RMS/non-IgE reaction. Of 60 children who received linezolid, 19 had previous reactions consistent with RMS, which should not preclude further vancomycin. Nevertheless, only 7 of 19 (37%) had a clear explanation for receiving linezolid instead of vancomycin compared with 32 of 39 (82%) children without previous vancomycin reactions (P <.001). Conclusions The vast majority of patients had vancomycin reactions consistent with RMS. These patients are at risk for unnecessary vancomycin avoidance and linezolid utilization. We propose that this may be related to how reactions appear in the electronic medical record.