Relação entre a concentração sérica do fenobarbital e parâmetros bioquímicos hepáticos em cães em tratamento crônico

Abstract

Epilepsy is one of the most frequent chronic neurological diseases in small animal practice, and phenobarbital is one of the main anticonvulsant drugs used to treat this condition in dogs. Despite its therapeutic efficacy, its use may be associated with hepatic alterations, making laboratory monitoring indispensable for these patients. This study aimed to evaluate the relationship between serum phenobarbital concentration and biochemical parameters indicative of liver injury and function in dogs undergoing chronic treatment with this drug. Eight dogs on continuous use of phenobarbital for at least six months were evaluated by measuring serum drug levels and analyzing laboratory parameters, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), albumin, total bilirubin and fractions, cholesterol, glucose, and urea. Statistical analysis was performed using Spearman's correlation coefficient. A very strong positive correlation was observed between serum phenobarbital concentrations and ALT, a strong positive correlation with GGT, and a strong negative correlation with albumin. No statistically significant correlations were observed with AST, total bilirubin, cholesterol, glucose, or urea. The results indicate that the chronic use of phenobarbital may be associated with specific hepatic biochemical alterations, involving both hepatocellular integrity and the synthetic function of the liver. It is concluded that periodic monitoring of serum phenobarbital concentration, combined with an integrated evaluation of hepatic parameters, is essential for the safe and individualized management of anticonvulsant treatment in dogs.