Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 12 2 2026 02 22 214 215 Padideh Ansar Department of Anesthesiology, Shohada-e-Tajrish Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Neda Tadjeddin Department of Anesthesiology, Shohada-e-Tajrish Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hamideh Ariannia Department of Anesthesiology, Shohada-e-Tajrish Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Faranak Behnaz Department of Anesthesiology, Shohada-e-Tajrish Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Seyedpouzhia Shojaei Department of Anesthesiology, Shohada-e-Tajrish Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2025 03 05 2025 03 10 This case report outlines a rare occurrence of accidental intrathecal injection of atracurium during spinal anesthesia for knee arthroscopy in a 22-year-old male patient. The solution intended to be bupivacaine mixed with fentanyl raised concerns after the ampule was discarded before verification. Fortunately, the patient showed no signs of paralysis or analgesia post-injection. The anesthesia team promptly administered high-dose methylprednisolone to reduce potential neurotoxic effects and monitored the patient closely in the Post-Anesthesia Care Unit. After six hours of stability and no neurological deficits, follow-up evaluations confirmed no lasting damage, allowing for safe discharge after 24 hours. This incident underscores the critical need for rigorous drug verification and safety protocols in anesthesia to prevent medication errors. https://aacc.tums.ac.ir/index.php/aacc/article/view/1223