Therapeutic drug monitoring with valproate-Why product selection is an important factor

Abstract

There is a modest collection of literature describing the pharmacokinetic and clinical differences between the extended-release form of divalproex sodium (Depakote ER ® ) and the delayed-release form (Depakote ® ). Published articles are quick to espouse the extended-release formulation, especially in the setting of seizure control. Reasons commonly cited include a longer dosing interval, improved patient compliance, a more consistent pharmacokinetic profile, and fewer side effects. There are fewer articles discussing these differences in the context of treating mental illnesses, namely bipolar affective disorder. This article aims to compare these two formulations of divalproex with a special focus on their pharmacokinetic profiles, uses in psychiatric illness, and the role of therapeutic drug monitoring. The patient case that follows will describe a scenario in which a patient was prescribed each formulation during an acute hospitalization.