This study was performed in order to determine the effects of valproic acid on serum free carnitine, β-hydroxybutyrate and blood ammonia. Serum free carnitine, β-hydroxybutyrate and blood ammonia levels were measured in 24 epileptic children and in 24 age and sex-matched controls. The mean serum free carnitine level was significantly lower in patients taking valproic acid (33.5 ± 13.1 nmol/ml) than in control subjects (50.8 ± 14.6 nmol/ml) (p < 0.001). The mean blood ammonia level was significantly higher in patients receiving valproic acid (93.9 ± 20.5 µg/dl) than in controls (79.6 ± 21.4 µg/dl) (p < 0.002). The mean serum β-hydroxybutyrate level was significantly lower in patients taking valproic acid (2.26 ± 2.24 mg/dl) than in controls (4.38 ± 2.43 mg/dl) (p < 0.001).

Our results support the decision that valproic acid induces hypo-carnitinemia, hypoketonemia and an increased blood ammonia level.

Keywords: blood ammonia, carnitine, valproic acid