Valproic acid adverse reaction

Valproic acid has been suspected to cause some adverse reactions through reduced serum biotinidase enzyme activity. The activity of this enzyme was determined in 57 children taking valproic acid, eight of whom had hyperammonemia and three of whom, all female, had hair loss in 17 children taking car-bamazepine and in 75 age- and sex-matched healthy controls no significant differences were found between the groups [328. ... 

Psychiatric Confusion, delirium, and dementia Using the French Pharma-covigilance database, 272 cases (153 women and 119 men) of confusion associated with valproic acid were selected [362 ]. This adverse reaction mostly occurred in patients aged 61-80 years and in 40% was observed during the first 2 weeks of valproic acid exposure. It was labeled as serious in almost 63% and its outcome was favorable in 82%. 

Bondon-Guitton E, Sommet A, Montastruc JL. French Association of Regional Pharmacovigilance Centres. Confusion a rather serious adverse drug reaction with valproic acid a review of the French Pharmacovigilance database. Pharmacopsychiatry 2009 42(2) 61-5. 

---