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The effects of valproic acid on liver function
Insights
Valproic acid (VPA) did not increase liver enzyme activity in epileptic children but enhanced D-glucaric acid (GLA) excretion. This VPA effect on GLA was also observed in guinea pigs, alongside liver cell changes.
Area of Science:
- Pharmacology
- Biochemistry
- Pediatric Neurology
Background:
- Valproic acid (VPA) is a widely used antiepileptic drug.
- Concerns exist regarding VPA's potential enzyme-inducing effects and hepatotoxicity.
- Gamma-glutamyltranspeptidase (GGT) is a marker for liver enzyme induction, while D-glucaric acid (GLA) excretion may reflect altered drug metabolism.
Purpose of the Study:
- To investigate the enzyme-inducing potential of VPA in children with epilepsy.
- To assess the effect of VPA on serum GGT activity and urinary GLA excretion.
- To explore the VPA-induced GLA excretion phenomenon in an animal model.
Main Methods:
- Serum GGT activity and urinary GLA excretion were measured in 32 epileptic children on VPA monotherapy.
- VPA was administered to guinea pigs to evaluate its effect on GLA excretion and liver histology.
- Statistical analysis was performed to determine the significance of observed changes.
Main Results:
- VPA monotherapy in children did not significantly alter serum GGT activity.
- VPA selectively enhanced urinary GLA excretion in epileptic children.
- In guinea pigs, VPA administration increased GLA excretion and caused cytoplasmic vacuolization in hepatic cells.
- A potential link between VPA-induced GLA excretion and hepatotoxicity was suggested but not confirmed.
Conclusions:
- VPA does not appear to induce GGT activity in children at the studied dosage.
- VPA selectively stimulates GLA excretion in both epileptic children and guinea pigs.
- Further research is needed to elucidate the relationship between VPA-induced GLA excretion and potential hepatotoxicity.
Abstract:
To study a possible enzyme-inducing potency of valproic acid (VPA) in children, serum gamma-glutamyltranspeptidase (GGT) activity in serum and D-glucaric acid (GLA) excretion in urine were measured in 32 epileptic children who were on sodium valproate monotherapy (29.6 +/- 10.3 mg/kg/day). VPA did not affect GGT activity, but it selectively enhanced GLA excretion. To approach this phenomenon experimentally an attempt was made to induce a similar effect in animals. In guinea pigs it was possible to provoke a VPA induced rise in GLA excretion. In addition, vacuolisation of the cytoplasm of the hepatic parenchymal cells was observed. The question of the possible relationship between VPA hepatotoxicity and stimulation of GLA excretion remains to be answered.