Key words:esophageal diverticulum, systemic lupus erythematosus, convulsion, drug concentration levels 〈Abstract〉 A fifty-year-old male was diagnosed as having systemic lupus erythematosus(SLE), complicated by Lupus nephritis, which was confirmed on kidney biopsy to be class Ⅴ of the WHO classification in January 1986. The patient began to develop epilepsy seizures since September 2004. Brain MRI scan findings suggested that the epilepsy was likely associated with multiple intracranial ischemic lesions. Afterwards, the patient had the repetition of epilepsy seizures on an irregular basis, regardless of his regular taking of an oral anticonvulsant such as phenobarbital. In addition, his renal dysfunction advanced slowly, and reached end-stage renal disease in July 2006. On November 16, 2007, he was emergently admitted to our hospital due to a generalzed epileptic seizure after hemodialysis treatment at a dialysis clinic. Blood examination showed that blood concentrations of phenobarbital rather varied among the measurements after taking the drug. After switching the route of drug administration to intramuscular injection, the blood concentration of phenobarbital increased and stablized, and then the seizures disappeared. We thought that this could be associated with poor control of epilepsy despite