High-flux hemodialysis without hemoperfusion is effective in acute valproic acid overdose

OBJECTIVE: To report a case of valproic acid treated successfully with high -flux hemodialysis without the addition of charcoal hemoperfusion. CASE SUMMARY: A 25-year-old white woman with a history of multiple suicide attempts and schizophrenia presented after ingesting an unknown amount of v alproic acid. She became comatose and developed hypotension and lactic acid osis as valproic acid concentrations increased to > 1200 mu g/mL (therapeut ic concentration 50-100). High-flux hemodialysis was performed for four hou rs; the calculated elimination rate constant (k(el)) during the procedure w as 0.2522 h(-1) with a half-life (t(1/2)) of 2.74 hours compared with posth emodialysis k(el) of 0.0296 h(-1) and t(1/2) of 23.41 hours, suggesting tha t high-flux hemodialysis effectively eliminates valproic acid. The patient' s hemodynamic status and mental function improved in conjunction with the a cute reduction in valproic acid concentrations. her subsequent hospital cou rse was complicated only by transient thrombocytopenia. DISCUSSION: Most literature reports of valproic acid overdose have describe d the use of charcoal hemoperfusion alone or in combination with hemodialys is to accelerate valproic acid clearance at toxic concentrations. However, the pharmacokinetic properties of valproic acid indicate that hemodialysis alone would be effective therapy for an acute valproic acid overdose. CONCLUSIONS: We suggest that toxic concentrations of valproic acid can be e ffectively reduced with high-flux hemodialysis without the addition of char coal hemoperfusion and its attendant risks.