Evaluation of the effect of phenobarbital administration on biochemistry profile with focus on serum liver concentrations in cats with epilepsy : a multi-center study

Phenobarbital (PB) is the most common antiseizure drug (ASD) used for
the management of feline epilepsy. In dogs, PB is known to cause serum
liver enzyme induction and hepatotoxicity especially after long-term
administration or high serum PB concentrations. In cats, insufficient evidence
is available to draw similar conclusions. The aim of this study was to
evaluate the effect of PB administration on the serum biochemistry profile
in cats with epilepsy. Medical records of four veterinary center were retrospectively
reviewed for cats with epilepsy receiving PB treatment. Serum
alkaline phosphatase, alanine transferase (ALT), aspartate transaminase and
gammaglutamyl transferase activities and total bilirubin, bile acids, glucose,
albumin, total protein, urea and creatinine concentrations before and during
PB administration were recorded. Serum PB concentration was also
recorded, when available. Thirty-three cats with a median age of 3 years
met the inclusion criteria. Idiopathic or structural epilepsy was diagnosed
in 25 (76%) and 8 (24%) cats, respectively. The follow-up period ranged
from 1 to 62 months. No statistically significant increase in serum liver
enzymes and other evaluated biochemistry parameters was found comparing
parameters at baseline to parameters during PB treatment. PB administration
did only result in serum hepatic enzyme induction in a minority of
cats and no increase was found for the other biochemical abnormalities in
cats. This strengthens the safety profile of PB as an ASD in cats.