Successful management and recovery of a dog with immune‐mediated thrombocytopenia following vincristine overdose

Objective To describe the management and outcome of a dog following a 10‐fold dosing error of vincristine. Case Summary A 2‐year‐old neutered female Toy Fox Terrier presenting for immune‐mediated thrombocytopenia was administered an accidental overdose of vincristine (0.2 mg/kg [2.71 mg/m2]). The dog was managed for severe gastrointestinal signs, neutropenia, and neurological consequences secondary to the overdose. Neurological signs included diffuse muscle tremors, limb hyperextension, and myalgia during the dog's hospitalization. Medical management consisted of aggressive supportive care in addition to novel strategies, including folinic acid, glutamic acid, and Tbo‐filgrastim. The dog was discharged from the hospital after 12 days of hospitalization and recovered completely within a month of the overdose with no lasting consequences. New or Unique Information Provided This is the first report of the successful management of severe vincristine overdose in a dog. Therapy included the use of Tbo‐filgrastim, folinic acid, and glutamic acid along with aggressive supportive care.