"Once-Daily Divalproex Similar to Twice-Daily Formulations in Seizure Control: Presented at AES"
By Paula Moyer
SAN DIEGO, CA -- December 8, 2006 -- People with epilepsy who switch from delayed-release divalproex (Depakote DR) to an extended-release (ER) formulation of the drug experience similar benefits in seizure control after the switch, according to research presented here at the annual meeting of the 1[st North American Regional Epilepsy Congress (NAREC).
The meeting is organized by the American Epilepsy Society (AES) jointly with the Canadian League Against Epilepsy.
The delayed-release formulation is taken on a twice-daily or 3-times-daily basis, and the ER formulation is taken once daily. The investigators conducted the study when the pharmacy at their facility, a county hospital, quit carrying the delayed-release formulation.
Richard T. Brannegan, DO, attending neurologist, Stroger Hospital of Cook County, Chicago, Illinois, and colleagues monitored their epilepsy outpatients prospectively to see if they had any changes in seizure frequency as well as in medication adverse effects after being switched and to see if they had any preferences between the 2 preparations.
The investigative team obtained data at the patient's index visit regarding seizure frequency over the previous 6 months, as well as information on adverse effects that might be related to divalproex, such as fatigue, gastrointestinal (GI) upset, hair loss, and weight change.
Patients completed a 20-item questionnaire about the effect, if any, that hand tremor had on various daily activities, and they were asked to copy an Archimedes spiral. The investigators also recorded the patient's weight at the initial visit, when the treatment was switched, and at 3 and 6 months. The switch resulted in an increase in total dose of approximately 20%.
The investigators also analyzed changes in seizure frequency, as well as any changes in adverse effects at 3 and 6 months. Two trained, blinded raters graded the patients' Archimedes spirals; they also asked patients which divalproex preparation they preferred and times per day that they used the ER formulation.
The investigators enrolled 47 patients, of whom 38 completed all 3 follow-up visits. There were no significant changes in seizure frequency 6 months after patients were switched to the ER formulation, although there was a nonsignificant trend for improvement in seizure frequency (P = .08). They also detected no changes in adverse effects regarding fatigue, GI upset, and hair loss, and patients' weights were unchanged after the switch.
The raters documented no significant changes in Archimedes spirals at 6 months. However, questionnaire responses about hand tremor in various activities showed significant improvement at 3 and 6 months after the switch (P = .03 P = .05, respectively). Among these patients, the majority (62%) preferred the extended-release formulation. However, more than 25% of patients used it in the same manner as the delayed-release formulation, with 10 using it twice a day, and 2 using it 3 times a day.
"Divalproex extended-release was as effective as divalproex delayed-release for seizure control in adult outpatients with a variety of seizure types," Dr. Brannegan concluded. "Adverse effects were generally similar with the two preparations although hand tremor was felt to be improved with the extended-release formulation."
The study was funded by Abbott Laboratories, which manufactures Depakote.
[Presentation title: Prospective Evaluation of Seizure Frequency and Side Effect Profile When Switching Adult Patients From Depakote (DR to Depakote ER at a Large Public Hospital. Abstract 2.109]
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