Alkaline phosphatase and its isoenzyme activity for the evaluation of bone metabolism in children receiving anticonvulsant monotherapy

AbstractThis study aimed to investigate whether carbamazepine, sodium valproate or phenobarbital as monotherapy in ambulatory epileptic children with adequate sun exposure have some effect on their bone metabolism based on the determination of total serum alkaline phosphatase (AP) levels and its bone isoenzyme activity. Blood samples were obtained from 118 epileptic children (37 on carbamazepine, 47 on sodium valproate and 34 on phenobarbital) and from corresponding healthy controls matched for age, gender and anthropometric parameters. AP and its liver, bone and intestinal isoenzyme levels, other common biochemical markers of bone and liver metabolism and drug levels were measured in the study participants. Patients on carbamazepine or phenobarbital had significantly elevated AP levels accompanied by increased bone and liver isoenzyme activity compared to controls. An increase of bone AP isoenzyme values, correlated with the duration of treatment ( r= 0.49, P= 0.002), was found in children on sodium valproate without, however, a concomitant significant elevation of total AP values. We conclude that children who receive antiepileptic drugs as monotherapy, even when residing in a Mediterranean country with adequate sunlight, may have their bone metabolism affected as indicated by the elevated levels of bone AP isoenzyme. This isoenzyme, but not total AP values, could therefore be used as a marker for the selection of patients who would be benefited by a thorough evaluation of their bone metabolism profile

Effect of sodium valproate monotherapy on serum uric acid concentrations in ambulatory epileptic children: A prospective long-term study

Purpose: Hyperuricemia has been shown to be related to cardiovascular morbidity and mortality. There is controversial data about the effect of sodium valproate (VPA) monotherapy on serum uric acid concentrations. The purpose of this study was to investigate by a long-term, prospective method, whether treatment with VPA monotherapy may alter serum uric acid concentrations and liver function tests in ambulatory epileptic children. Material and methods: Serum uric acid concentrations were determined in 28 ambulatory epileptic children before and at 6, 12 and 24 months of VPA monotherapy. Serum concentrations of biochemical markers of liver and renal function, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), gamma-glutamyltransferase (gamma-GT) and creatinine (Cr) were also measured before and at 6, 12 and 24 months of VPA monotherapy. Serum VPA concentrations remained within the therapeutic range (50-100 mg/L) during the period of study. Results: No statistically significant changes in serum Uric acid concentrations were found at 6, 12 or 24 months of treatment. Serum ALT concentrations were significantly increased at 6 and 12 months of treatment, AST concentrations at 6 and 12 months of treatment and LDH concentrations at 12 months of treatment. Conclusions: VPA monotherapy does not have a significant effect on serum uric acid concentrations in ambulatory epileptic children. Further studies are needed to definitively address whether it would be useful for physicians to routinely check for elevated serum uric acid levels in children treated with VPA. (C) 2006 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved