741. Evaluation of Serotonin Syndrome with Linezolid and Serotonergic Agents at an Academic Medical Center

Abstract

Abstract Background The risk of linezolid-associated serotonin syndrome based on the potency and number of serotonergic agents is unclear. Thus, the primary outcome was to evaluate the incidence of serotonin syndrome among hospitalized patients who are concurrently receiving linezolid with or without serotonergic agents. Secondary outcomes were to assess the potency, agent selection, and number of serotonergic agents. Methods This was a single-center, retrospective cohort study of hospitalized patients >18 years of age who received >1 dose of linezolid with or without a concurrent serotonergic agent between 1/1/14–6/30/2021. Patients were excluded if < 18 years of age, had linezolid ordered but not administered, were pregnant, or incarcerated. Up to five concurrent serotonergic agents were recorded and potency was divided into low, moderate, and high potency based on if the drug strength was < 33%, 33–66%, and >66% of the maximum daily dose, respectively. Serotonin syndrome was identified by searching patients’ electronic medical record for ‘serotonin syndrome’ or ‘serotonin toxicity’. If either term was identified, Hunter and Sternbach criteria were applied. Descriptive statistics including number (percentages) and mean (standard deviation) were used. Results Of 2022 patients screened, 1743 were included. Mean age, weight, and linezolid duration were 58.5 years, 90.7 kg, and 4.1 days, respectively. Of patients included who received linezolid, 43.2%, 16.2%, 5.7%, 1.4%, and 0.5% received at least one, two, three, four, and five concurrent serotonergic agents, respectively. Most patients received either a moderate and/or high potency (53.8%) compared to a low potency serotonergic agent (46.2%). Only 2 patients (0.11%) were identified with ‘serotonin syndrome’ or ‘serotonin toxicity’. Patient 1 received escitalopram moderate potency and trazodone low potency but did not meet either Hunter or Sternbach criteria. Patient 2 received duloxetine moderate potency, vilazodone moderate potency, and metoclopramide low potency but only met Sternbach criteria. Conclusion Serotonin syndrome among hospitalized patients receiving linezolid with other serotonergic agents was exceedingly rare, even among those who received multiple and more potent serotonergic agents. Disclosures Wesley D. Kufel, Pharm.D., BCPS, BCIDP, AAHIVP, Melinta: Grant/Research Support|Merck: Grant/Research Support|Theratechnologies, Inc.: Advisor/Consultant.