Effects of phenobarbital administration on results of serum biochemical analyses and adrenocortical function tests in epileptic dogs
Chauvet, A.E.; Feldman, E.C.; Kass, P.H.
Journal of the American Veterinary Medical Association 207(10): 1305-1307
1995
ISSN/ISBN: 0003-1488 PMID: 7591923 Document Number: 448780
Objective-To determine what effects long-term phenobarbital administration to dogs with epilepsy would have on serum biochemical factors and adrenocortical function. Design-Prospective, uncontrolled study. Animals-Five dogs with idiopathic epilepsy. Procedure-Serum total protein, albumin, total bilirubin, and cholesterol concentrations and serum alkaline phosphatase and alanine aminotransferase activities were measured before and 2 weeks, 6 months, and 12 months after initiation of phenobarbital administration. Endogenous ACTH concentration was measured, and ACTH stimulation and low-dose dexamethasone suppression tests were performed at the same time. Results-Serum albumin concentration decreased in 4 of 5 dogs, and serum cholesterol concentrations decreased in all 5 dogs over the course of the study. Serum alkaline phosphatase concentration and alanine aminotransferase activities increased over time, and were greater than the upper reference limits in 4 of the 5 dogs by the end of the study. EndogenouS ACTH concentration increased in all dogs but remained within reference limits. Plasma ACTH-stimulated aldosterone concentration increased over the course of the study. Plasma cortisol concentration did not suppress, after administration of dexamethasone, in 1 dog after 6 and 12 months of phenobarbital administration. Clinical Implications-Although endogenous ACTH concentration should be normal in dogs receiving phenobarbital, results of ACTH stimulation and dexamethasone suppression tests may be altered. Serum albumin and cholesterol concentrations, and serum alkaline phosphatase and alanine aminotransferase activities may also be abnormal.