Lerario MP, Grotta JC, Merkler AE, et al. - Using inpatient and outpatient claims between 2008 and 2015 from a nationally representative 5% sample of Medicare beneficiaries, researchers conducted a retrospective cohort study to ascertain if individuals with stroke who receive thrombolytic agents face a higher risk of anaphylaxis than those who do not receive thrombolytics. Participants in the study were patients who were ≥ 65 years old and hospitalized with acute ischemic stroke, defined by validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. Of the 66,989 stroke individuals, the 3,176 who had intravenous thrombolysis more frequently had atrial fibrillation and more frequently received intravenous contrast dye but were otherwise comparable in terms of demographics and comorbidities. The data presented in this work showed a significant link between receipt of intravenous thrombolysis and anaphylaxis after adjustment for demographics, comorbidities, contrast dye, mechanical thrombectomy, and history of allergies. A similar association was found for anaphylactic shock. Although a rare occurrence, among patients who received intravenous thrombolysis, the risk of anaphylaxis was significantly higher among those with acute ischemic stroke.