Extrapyramidal side effects in a blue and gold macaw (Ara ararauna) treated with amitriptyline

Extrapyramidal side effects were observed in a 17-year-old female blue and gold macaw (Ara ararauna) that presented with an acute onset of dystonic reactions (repetitive and abnormal motions as well as head bobbing) and akathisia (restlessness and pacing) a few hours after a single partial dose of amitriptyline (5 mg/kg) orally. The patient was concurrently being treated with meloxicam (1 mg/kg orally every 12 hours) and had previously been treated with hydroxyzine, prednisolone, leuprolide acetate, and deslorelin acetate, for chronic feather damaging behavior. The patient was hospitalized and treated with diphenhydramine (2-3 mg/kg intramuscularly [IM] every 12 hours, 3 doses), propranolol (0.04 mg/kg IM once), cyproheptadine (1.2 mg/kg orally twice), midazolam (0.2-3 mg/kg IM as needed), and supportive care. Resolution of clinical signs was not achieved with any attempted therapy, but the dystonia and akathisia progressively resolved during 5 days. Residual signs were still visible at discharge. The severe adverse effects encountered with what appears to be an overdose of amitriptyline in this case is a reminder that species-specific pharmacologic and toxicologic studies on tricyclic antidepressants are needed and that psychotherapeutic agents may be associated with neurologic adverse effects, especially when using extrapolated doses. In addition, this case illustrates that tricyclic antidepressant must be started at a low dose in birds and follow a gradual titration approach to avoid adverse effects and maximize treatment efficacy.