Effects of phenobarbital administration on results of serum biochemical analyses and adrenocortical function tests in epileptic dogs.
OBJECTIVE
To determine what effects long-term phenobarbital administration to dogs with epilepsy would have on serum biochemical factors and adrenocortical function.


METHODS
Prospective, uncontrolled study.


METHODS
Five dogs with idiopathic epilepsy.


METHODS
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.


CONCLUSIONS
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.
Chauvet
A E
AE
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Feldman
E C
EC
Kass
P H
PH
D000302:Adrenal Cortex / Q000187:drug effects* / Q000502:physiology; D000304:Adrenal Cortex Function Tests / Q000662:veterinary; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000410:Alanine Transaminase / Q000097:blood; D000450:Aldosterone / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001663:Bilirubin / Q000097:blood; D001774:Blood Chemical Analysis / Q000662:veterinary; D001798:Blood Proteins / Q000032:analysis / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D003907:Dexamethasone; D004283:Dog Diseases / Q000097:blood / Q000188:drug therapy*; D004285:Dogs; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy / Q000662:veterinary*; D006854:Hydrocortisone / Q000097:blood; D008099:Liver / Q000187:drug effects* / Q000502:physiology; D010634:Phenobarbital / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D011446:Prospective Studies; D012709:Serum Albumin / Q000032:analysis / Q000187:drug effects
D001798:Blood Proteins; D012709:Serum Albumin; D000450:Aldosterone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D002784:Cholesterol; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D001663:Bilirubin; D006854:Hydrocortisone; D010634:Phenobarbital