Hemodiafiltration and High-Flux Hemodialysis Significantly Reduce Serum Valproate Levels Inducing Epileptic Seizures: Case Report

cally appearing after her HD sessions. At that time she was treated with postdilutional HDF, with 20 l infusate per 4.5-hour session, FX80 dialyzer (helixone, 1.8 m 2 , Fresenius Medical Care, Bad Homburg, Germany), blood flow 300 ml/min, AVF as vascular access. Valproate concentrations were measured before and after HDF approximately every 2 weeks and were 666 8 53 (range 567–750, therapeutic levels 345– 690)  mol/l before and 341 8 63 (range 261–462) mol/l after HDF, which represents a 49 8 9% (range 38–59%) decrease Sir, Valproate is used in the treatment of some forms of epilepsy. A recent review of antiepileptic drugs in patients with kidney disease [1] reports that dose supplementation after hemodialysis (HD) is not routinely recommended. It refers to some rather old literature, reporting that (lowefficiency) dialysis removes only 20% of administered valproate dose [2] and that (low-efficiency) HD (combined with hemoperfusion) produces only a transient drop in valproate concentration [3] . A significant removal of valproate with (highefficiency) HD has been reported in recent years, but only in cases of valproate intoxication at serum concentrations up to 10 times therapeutic levels [4, 5] . The previously mentioned review therefore remarks that the effect of high-efficiency HD on clearance and seizure activity in patients on chronic HD is not known. We report a case of a 23-year-old female HD patient (dry weight 57 kg, primary renal disease focal segmental glomerulosclerosis) who has been on HD for 3 years. She has had epilepsy since the age of 5 years and was treated with entericcoated valproic acid (Apilepsin ) 1,500– 1,800 mg on the non-dialysis day, with an additional 150–300 mg on the dialysis day – taken before or during HD. As hemodiafiltration (HDF) was introduced in our center in 2006, she began to experience short partial complex seizures typiPublished online: June 4, 2008