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 patients with stroke who receive thrombolytic agents face a higher risk of anaphylaxis than those who do not receive thrombolytics. 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, were included. Of the 66,989 patients with stroke, 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. Although a rare occurrence, the risk of anaphylaxis was significantly higher among those receiving intravenous thrombolysis in patients with acute ischemic stroke.