A Rare Case of Valproic Acid Toxicity Requiring Hemodialysis

Valproic acid poisoning can have mild to fatal consequences depending on its body concentration. There are rare case reports and barely any known controlled studies on the use of hemodialysis as a last treatment resort. We report a rare valproic acid poisoning case at One Brooklyn Health/Interfaith campus, New York City, warranting intubation and hemodialysis. The patient is a 47-year-old male with a past medical history of seizure disorder, polysubstance use disorder, schizophrenia, and gastroesophageal reflux disease (GERD) who was brought to the medical emergency department (ED) for intentional valproic acid overdose with 60 tablets of his prescribed home Depakote DR 500 mg (~30 g). The patient's other outpatient medications included valproic acid, trazodone, acetaminophen, famotidine, fluoxetine, folic acid, hydrocortisone-aloe, multivitamin, nicotine polacrilex, and thiamine. The patient's initial blood tests showed high valproic acid, ammonia, ethanol, and lactate. About six hours after ED admission, the patient became somnolent, desaturated to 74% on a non-rebreather oxygen mask, warranting intubation and hemodialysis after noticing persistently high serum concentrations of valproic acid. The relatively low molecular weight (144 Daltons) and low volume of distribution of valproic acid suggest a potential benefit from hemodialysis, especially at a serum concentration of >850 mg/L or in the event of a shock. In this patient, mentation and stability status were improved after hemodialysis. Hemodialysis appears to be the last treatment resort for severe valproic acid poisoning.