Cw. Cranor et al., CLINICAL AND ECONOMIC-IMPACT OF REPLACING DIVALPROEX SODIUM WITH VALPROIC ACID, American journal of health-system pharmacy, 54(15), 1997, pp. 1716-1722
The impact of replacing divalproex sodium with valproic acid on patien
t outcomes and direct drug costs was studied. Before-and-after medical
chart review was performed in a state-supported facility for mentally
retarded adults in which a pharmacy and therapeutics (P&T) committee
recommended replacement of divalproex with valproic acid. Patients wer
e studied if they had received divalproex for at least three months an
d if their antiepileptic drug was changed from divalproex to valproic
acid between October 1993 and June 1994. Clinical, economic, and presc
ribing-pattern data were recorded for the periods extending 12 months
before and 18 months after the change in therapy. Data for 46 patients
were analyzed. Replacing divalproex with valproic acid was effective
in 41 (89%) of the patients. There was no significant difference betwe
en the divalproex and valproic acid periods in seizure rate or frequen
cy of new drug therapy for GI disorders. Between fiscal year 1992-93 a
nd fiscal year 1995-96 there was a 56% decrease in total direct divalp
roex plus valproic acid costs, including drug products and packaging m
aterials and labor. The rate of valproic acid prescriptions increased
steadily after the replacement was recommended, and then plateaued. Re
placing divalproex sodium with valproic acid in a group of institution
alized mentally retarded adults with epilepsy was clinically effective
and economically advantageous.