Polyneuropathy caused by chlorprothixene

Seven chronic psychiatric patients developed signs of polyneuropathy mainly in the lower limbs after receiving chlorprothixene (500-1800 mg/d) from 3 to more than 24 months. The most prominent electroneuromyographic findings were decreased or not measurable motor conduction velocities of the peroneal nerves. Electromyography showed signs of denervation in the leg muscles in all the patients, and also in the upper limbs in 4 of them. The signs of polyneuropathy gradually subsided after withdrawal of chlorprothixene. Thus, chlorprothixene may cause a toxic, dose-dependent, reversible polyneuropathy.