TITLE:
Altered Mental Status and Hyperammonemia after Overdose of Valproic Acid with Therapeutic Valproic Acid Concentrations
AUTHORS:
Evan S. Schwarz, Mark Thoelke
KEYWORDS:
Valproic Acid, L-Carnitine, Levocarnitine, Overdose, Toxicity
JOURNAL NAME:
International Journal of Clinical Medicine,
Vol.5 No.10,
May
13,
2014
ABSTRACT: Valproic acid is
used in the treatment of multiple disorders. Adverse effects from valproic acid
include hepatotoxicity, hypotension, metabolic acidosis, and decreased mental
status. Valproic acid also causes hyperammonemia. Many physicians assume that this
is due to a supratherapeutic valproic acid concentration; when in fact, it can
occur with therapeutic valproic acid concentrations. This is because the
hyperammonemia may be related to carnitine deficiency and disruption of the
urea cycle, which can both occur with therapeutic valproic acid concentrations.
We report a patient presented to the emergency department with alteration of
mental status after ingesting valproic acid for recreational purposes, who
developed hyperammonemia with a therapeutic valproic acid concentration.