Cognitive function in adult epileptic patients on long-term sodium valproate

A battery of psychometric tests was administered to 102 adult patients with epilepsy. Forty-eight were receiving long-term treatment with sodium valproate (VPA) as monotherapy, and 28 took a combination of VPA with either carbamazepine or phenytoin. An additional 26 patients were untreated, and the tests were also administered to 24 nonepileptic controls. The polypharmacy group performed significantly less well than the other groups in 6 of the 11 tests. Overall, there were no differences in performance between the VPA monotherapy patients and both the drug-free groups. However, patients with higher total and free VPA concentrations reported more sedation and scored less well on the threshold detection task. Patients were divided into those “tolerant” and “intolerant” to the drug in terms of these two tests. The “intolerant” group had a significantly earlier age of onset of epilepsy and a lower nonverbal IQ. Monotherapy with VPA is unlikely to impair cognitive function and may be a suitable choice if cognitive function is an important consideration.