Relationship between changes in drug score, D-glucaric acid excretion, and gamma-glutamyltransferase and beta-glucuronidase serum activities during anticonvulsant treatment.

The purpose of this study was to investigate the relationship of changes in the enzyme-inducing anticonvulsant daily dosage (drug score) to variations in urinary D-glucaric acid excretion and gamma-glutamyltransferase and beta-glucuronidase serum activities. These biochemical determinations were carried out before and after a mean period of 5.0 years in 16 adult epileptic patients (8 men and 8 women) treated with phenobarbital, phenytoin and/or carbamazepine and with a good therapeutic compliance. A significant correlation between D-glucaric acid excretion and drug score was obtained (r=0.508, p<0.001). When the interindividual variation was diminished by assessing the changes of these variables in the same subjects, the correlation was better (r=0.836, p<0.001). However, a statistical significance was not attained between the gamma-glutamyltransferase or beta-glucuronidase and drug score changes. Therefore the urinary excretion of D-glucaric acid appears to be more sensitive to changes in anticonvulsant drug score than serum gamma-glutamyltransferase and beta-glucuronidase.