Trial of Sodium Valproate in Amyotrophic Lateral Sclerosis

Inclusion Criteria: Definite, probable, or probable-laboratory supported ALS according to the revised El Escorial World Federation of Neurology criteria. Intake of riluzole 50 mg twice a day (bid) A disease duration at inclusion of more than 6 months and less than 36 months [inclusive] (disease onset is defined as the date of first symptoms excluding muscle cramps and fasciculations) Vital capacity (VC%) ≥ 70% of normal value (slow expiration, best of a minimum of three and a maximum of five measurements, with a respiratory function validly assessable and a spontaneous, non-assisted ventilation) Ages 18 - 85 years (inclusive) Capable of thoroughly understanding the trial information given; has signed the informed consent. Exclusion Criteria: Tracheostomy, tracheostomal ventilation of any type, non-invasive ventilation more than 16 hours/ day, or supplemental oxygen during the last three months prior to inclusion. Any medical condition or intoxication known to have an association with motor neuron dysfunction, which might confound or obscure the diagnosis of ALS. Presence of any concomitant life-threatening disease or any disease or impairment likely to interfere with functional assessment. Confirmed hepatic insufficiency or abnormal liver function (ASAT, ALAT greater than twice the upper limit of normal range).