Abstracts

To describe the incidence and characteristics of myoclonus occurring in hospitalized patients with end stage renal disease(ESRD) exposed to gabapentin.
Retrospective review of charts for occurrence of myoclonus in patients with ESRD hospitalized during a 18 month period who were exposed to gabapentin. Clinical details including type of myoclonus, dose of gabapentin, EEG findings and duration of symptoms related to gabapentin exposure and reduction were analyzed.
Three patients from a total of 71 patients with ESRD exposed to gabapentin were documented to have myoclonus. Gabapentin dose at which myoclonus occurred ranged from 10 to 16mg/kg and occurred within 2 month of onset of treatment. Myoclonus was charaterized as multifocal involving all extremities in all patients. EEG did not show any cortical epileptiform discharges associated with myoclonus. Resolution of myoclonus was observed in all patients with discontinuation of gabapentin and occurred between 2 and 8 days of stopping the medication.
Gabapentin at low dose is associated with myoclonus in patients with ESRD and occurs at frequencies similar to that described in epilepsy patients (Asconape J, 1996). EEG findings suggest a noncortical mechanism as reported previously in patients with seizures. Myoclonus in this patient group was more disabling and required discontinuation of gabapentin. Resolution of myoclonus took longer and is probably related to delayed renal excretion. The mechanism of production of these symptoms is unclear but may imply a spinal mechanism as has been previously suggested.