Introduction: Valproic acid is increasingly used in the
treatment of epilepsy, and also prescribed for bipolar
affective disorders, schizoaffective disorders, schizophrenia and migraine prophylaxis. We describe two case reports involving valproic acid intoxication with ingestion of ethanol.
Methods: One patient was treated by supportive care, one patient received haemodialysis.
Results: From analysis of plasma concentrations before
and during haemodialysis (pre- and post-filter) it is
shown that valproic acid can be effectively eliminated by
haemodialysis when plasma levels are way above 100 μg/ml. In the literature, plasma protein binding is reported to be around 90% for levels within the therapeutic range. In our patient plasma protein binding was around 50% after treatment with haemodialysis.
Conclusion: These findings make haemodialysis in
valproic acid intoxication a sensible therapeutic option
with increasing efficiency when plasma concentration is
high. Furthermore our findings suggest that lowering
valproic acid concentrations to a therapeutic level by
haemodialysis does not necessarily result in an immediate, simultaneous increase in plasma protein binding of valproic acid.