Treatment of epileptic patients with valproic acid does not modify plasma and urine short-chain-fatty acids.

The purpose of this study was to evaluate the possible modifications of the plasma and urine short-chain-fatty acid (SCFA) patterns indiced by treatment with valproic acid (VPA). Increased amounts of SCFAs in patients under VPA treatment may explain the presence of VPA-induced hyperammonemia, toxic encephalopathies and rarer Rey-like syndromes recently observed. For this reason we assayed SCFA levels in the plasma and looked for propionic acid in the urine of 10 epileptic patients to whom it was decided to add VPA to their previously unsatisfactory anti-epileptic treatment. This was carried out prior to and during therapy with VPA. 5 of these patients developed toxic encephalopathy with hyperammonemia induced by VPA. Our data show that plasma and urine SCFAs are not modified by VPA treatment. This is so even in patients who have toxic encephalopathy with hyperammonemia indiced by this drug.