2231. Safety of Nebulized Colistin as Adjunctive Treatment of Lower Respiratory Tract Infections

Abstract

BackgroundSystemic antibiotics used in treatment of drug-resistant lower-respiratory tract infections (LRTI) may have poor lung penetration or narrow therapeutic indices. Nebulized administration of colistin allows direct instillation of active agent to maximize concentrations at the site of infection. Theoretically, local administration also avoids treatment-limiting toxicities and adverse drug reactions (ADR). Current literature supports efficacy of nebulized colistin as adjunctive treatment for LRTI. However, there is a paucity of data surrounding safety and tolerability of this administration technique.MethodsThe electronic medical record (EMR) was queried to identify patients treated with nebulized colistin between January 1, 2016 and December 31, 2018. The following data were collected from the EMR and hospital ADR reporting systems: demographics, treatment regimen, serum creatinine (SCr), concomitant nephrotoxins, infecting pathogen, treatment-emergent ADRs, and drug toxicities. The primary outcome was prevalence of renal (acute kidney injury [AKI]), neurologic (seizure, visual disturbance), or respiratory (bronchospasm) ADRs secondary to colistin nebulization therapy. AKI was defined according to the RIFLE criteria.ResultsThirty-two patients were administered nebulized colistin during the study period. Approximately 19% of patients had a baseline renal impairment. Cultures were positive in 29 patients of which 11 organisms were resistant to all tested antimicrobials. The most common infecting pathogen was A. baumanii (n = 15) followed by K. pneumoniae (n = 9). The median duration of therapy was 4.6 days. Seventeen patients (53.1%) were exposed to concomitant nephrotoxins. Three patients experienced AKI of which two received simultaneous furosemide and one had underlying renal dysfunction and received concomitant vancomycin. The one observed neurologic reaction, seizure, occurred in a patient with underlying epilepsy. No patients had documented visual disturbances or bronchospasm.ConclusionThe results of our study are consistent with the principle that localized administration of colistin results in a lower incidence of systemic adverse events. Nebulized colistin is a safe adjunct for managing LRTI. Renal, pulmonary, and neurologic reactions in this study were likely not treatment-related. Disclosures All authors: No reported disclosures.