Clinical and pharmacokinetic observations on sodium valproate - a 5-year follow-up study in 100 children with epilepsy.

Results of clinical and pharmacokinetic observations on sodium valproate (VPA) are reported from a long-term study in 100 children with epilepsy. VPA is the drug of choice in patients with absences. VPA may preferably be chosen as the first drug in patients with atonic seizures partly because all treatment of these seizures is uncertain, and the effect of VPA may be striking, without side effects. When starting with VPA the great problem of drug interactions is avoided. Treating patients with intractable epilepsy has shown that VPA may be effective in all seizure types regardless of the EEG-findings. However, generalized paroxysms of spike and wave complexes in the EEG are a good prognostic sign especially when fairly regular. Side effects are few when using enteric coated tablets, but toxic effects may be serious. Control schemes of blood and liver functions are necessary. Drug fasting serum level monitoring is mandatory, especially when VPA is given in combination with other anti-epileptic drugs as interactions with these are pronounced. Optimal clinical effect is usually seen on serum levels between 300 and 600 microgram mol/l, which may be obtained by giving 10-20 mg/kg daily assuming that the patient is receiving VPA monotherapy, which should always be aimed at. Comedication may have to be withdrawn to obtain therapeutic serum levels of VPA due to drug interactions.