Suspected Obstructive Sleep Apnea Successfully Treated with Ondansetron in a Pug

Obstructive sleep apnea (OSA) has been uncommonly reported in dogs and is often associated with brachycephalic obstructive airway syndrome (BOAS). OSA independent from BOAS has been rarely reported. Treatment of OSA with ondansetron has only been reported in one dog and has not been reported in a breed commonly affected by BOAS. Here, we report the case of a pug with episodes of OSA despite appropriate treatment of BOAS. Administration of ondansetron led to a rapid and near-complete resolution of the clinical signs, with a follow-up of 3 mo. OSA independent of BOAS should be considered as a differential diagnosis in dogs that present for sleep-disordered breathing without exercise intolerance after appropriate treatment for BOAS. Use of certain serotonin antagonists may be useful as a treatment option for these cases.