The frequency of reversible parkinsonism and cognitive decline associated with valproate treatment: A study of 364 patients with different types of epilepsy

Purpose: We report the frequency of parkinsonism and cognitive decline (P/CD) in patients treated with valproate (VPA) after 1 year of treatment and at least 1 year of follow-up. Methods: Three hundred sixty-four patients with various epileptic syndromes and seizure types were treated with VPA mono- or polytherapy for more than 1 year. Results: We found five cases of P/CD (1.37%; 95% CI, 0.18-2.56%). Among 140 patients with different adverse effects (AEs) of VPA, P/CD were among the rarest in frequency but significant in terms of drug discontinuation (five of 17). Conclusions: Early identification of this type of AE and discontinuation of the drug led to complete recovery in affected patients.