Addisonian crisis in a dog treated with phenobarbitone

• Published in: Australian veterinary journal 2015-04, Vol.93 (4), p.105-108
• Main Authors: Simerdova, V, Hajek, I, Schanilec, P
• Format: Article
• Language: English
• Subjects: Acute Disease; Addison Disease - chemically induced; Addison Disease - veterinary; adrenal insufficiency; Animals; Anticonvulsants - adverse effects; cytochrome P‐450 enzyme system; Dog Diseases - chemically induced; Dogs; Epilepsy, Generalized - drug therapy; Epilepsy, Generalized - veterinary; Female; Medical treatment; Phenobarbital - adverse effects; phenobarbitone
• ISSN: 0005-0423; 1751-0813
• DOI: 10.1111/avj.12301

Background A 2‐year‐old intact female Irish Setter was presented with a 1‐week history of anorexia, lethargy, vomiting and diarrhoea. Previous medical therapy included a 3‐week treatment with phenobarbitone for suspected idiopathic epilepsy. In humans, phenobarbitone accelerates metabolism of both exogenous and endogenous steroids. Case report Based on history, the physical examination showing abnormal mentation and laboratory abnormalities including azotaemia, hyponatraemia and hyperkalaemia, Addisonian crisis was suspected. An adrenocorticotropic hormone stimulation test was performed and confirmed the diagnosis. Treatment with intravenous fluid therapy, glucocorticoids and mineralocorticoids led to a resolution of clinical signs in 3 days. Conclusion To the authors' current knowledge, this is the first reported case of Addisonian crisis in a dog most probably related to phenobarbitone administration. As Addisonian crisis can be life‐threatening, clinicians should be aware of this adverse effect of phenobarbitone and use it cautiously in dogs with borderline hypoadrenocorticism.