Clinical Experiences High‐flux hemodialysis in the treatment of severe valproic acid overdose: A case report

Introduction: Hemoperfusion, with or without hemodialysis, has been used to treat patients suffering from severe valproic acid poisoning. We report a patient suffering from severe valproic acid intoxication who was treated effectively with high-flux hemodialysis alone. Case: A 20-year-old man with a history of bipolar disorder was admitted after having ingested unknown amounts of valproic acid (Depakote®), prednisone, and erythromycin. He was agitated and obtunded but hemodynamically stable initially. Serum valproic acid level was 1,028 μg/mL. Urine toxicology screen as well as serum levels of ethanol, acetaminophen, and acetylsalicylic acid levels were negative. A gastric lavage was followed by activated charcoal instillation. Subsequent myoclonic twitchings that progressed to continuous seizure activity were managed with intravenous lorazepam therapy and endotracheal intubation. Serum valproic acid value measured two hours after admission remained elevated at 1,046 μg/mL. Hemodialysis was performed continuously for 10.5 hours using a high-flux, polysulfone dialyzer (Polyflux 21S, Fresenius Medical Care, Lexington, MA), a dialyzer blood flow of 200–300 mL/min, and a dialysate flow of 500 mL/min. The therapy brought about a fall in serum valproic acid level to 110 μg/mL and a complete recovery of the patient. Discussion: Valproic acid (144 Dalton) is 90–95% protein-bound at therapeutic serum values. However, in the face of an overdose, the unbound fraction rises because of saturation of protein-binding sites. This unbound fraction is readily dialyzable. We suggest that high-flux hemodialysis is effective in the treatment of severe valproic acid poisoning.