Methods After institutional review board approval (Thomas Jefferson University, Control# 22E. 056), the records from three institutions were queried over the date range January 1, 2013 to January 1, 2022 for patients who (1) received a ketamine infusion for≥ 12 cumulative hours and (2) had an international classification of disease (ICD) code associated with bladder dysfunction (online supplemental table 1) or a consultation with urology or gynecology within 90 days of treatment. Neither had evidence of bladder injury. Table 1 Patient demographics, ketamine dosing, and hospitalization details Patient or treatment characteristic, n= 116 Result Treatment site, N (%) University of Virginia 93 (80) Thomas Jefferson University 15 (13) Mayo Clinic—Florida 8 (7) Age in years, median (range) 53 (1–83) Sex, N (%) Male 68 (59) Female 48 (41) Body mass index in kg/m2, median (range) 28.2 (13.3–47.9) Type of admission, N (%) Medical 31 (27) Surgical 85 (73) Surgical specialty, N (%) Vascular/cardiothoracic 30 (26) Neurosurgery 14 (12) General 13 (11) Orthopedics 8 (7) More than one specialty/mixed 7 (6) Gynecological/urological 6 (5) Otolaryngology/plastic surgery 1 (1) Indication for ketamine, N (%) Postoperative pain 79 (68) Acute non-operative pain 21 (18) Intensive care unit sedation 13 (11) Complex regional pain syndrome/migraine 3 (3) Median ketamine infusion dose in mg/h, median,(range) 13.4 (4.8–409.8) Total duration of ketamine infusion in hours, median (range) 49 (12–746) Total dose of ketamine administered in mg, median (range) 732 (77–115,758) Likelihood of ketamine involvement in bladder complaint Unlikely 114 Possibly likely 2 Likely 0 Discussion Survey data have suggested that about 26% of respondents who admitted to illicit ketamine use in the past 12 months experienced at least one urinary tract symptom. 4 For ketamine use disorder patients with confirmed cystitis, hematuria was a universal finding. 3 While the exact prevalence of cystitis is not known, survey data reveal that about 1.5% of illicit users reported hematuria. 4 Our data suggest that hematuria is rare in patients prescribed ketamine for medical purposes. Twitter@ ESchwenkMD Contributors SP helped design the study, analyze data, and write the manuscript; PEA helped design the study and write the manuscript; PP helped collect data and write the manuscript; DAE helped collect data and write the manuscript; MPP helped collect data and write the manuscript; FJ-R helped collect data and write the manuscript.