Successful treatment of valproic acid overdose with hemodialysis.

A 43-year-old woman took a large amount of depakote (divalproex, a slow-release form of valproate), became comatose, and developed severe hypotension refractory to fluid resuscitation and high-dose vasopressors. The serum valproic acid (VPA) concentration on admission was 1,380 microgram/mL (therapeutic range, 50 to 100 microgram/mL). She also had metabolic acidosis, thrombocytopenia, and normal renal and liver functions. Hemodialysis was initiated 4 hours after presentation. After 6 hours of hemodialysis with a high-flux dialyzer, her serum VPA concentration decreased from 940 microgram/mL to 164 microgram/mL, coincident with improvement in clinical status. The half-life of VPA was reduced to 2.4 hours with hemodialysis, whereas it was 7.2 hours before the procedure. Hemodialysis could be a valuable therapeutic intervention in VPA toxicity.