Abstracts

Weight gain is associated with valproic acid / divalproex sodium therapy. However, long-term data which quantifies weight changes seen in epilepsy patients receiving the drug is lacking. We report on the long-term changes that occur in patients taking the drug., Patients started on valproic acid (VPA) in the form of divalproex sodium at Penn State, Milton S. Hershey Medical Center were offered the opportunity to participate in the study. Initial weights were recorded prior to starting therapy. Weights were recorded at each visit on the same digital scale. Concomitant medications were recorded., Forty-two patients entered the study. One was lost to follow-up, leaving 41 patients for analysis. There were 17 female and 24 male patients. Mean age was 33.1 years with a range of 17 to 69 years of age. Focal onset seizures were present in 27 patients, 5 were primary generalized, and 9 patients had features of both, making it difficult to determine the class. Mean VPA dosage was 1659 mg/day with mean VPA doses ranging from 500 - 4846 mg/day. Time on therapy ranged from 12 - 138 months with a mean of 56 months. Mean starting weight was 75.4 kg with a range from 46.4 - 131.8 kg.
Weight gain was defined as an increase in weight of 5% or more while on VPA therapy. Weight gain was seen in 26 patients (63.4%) with the mean weight gained at time of maximum weight being 19% of initial body weight. Weight gain ranged from 5.18 % - 56.5% of initial weight. Four patients did not maintain maximum weight and by the end of the study, only 22 patients (53.7%) had weights greater than 5% of start weights. Mean time to maximal weight gain was 44.2 months, with a range of 10 - 124 months. Male patients had a higher tendency toward weight gain, with 17 of the 24 males (70.8%) experiencing weight gain. Of 17 female patients, 9 (52.9%) demonstrated weight gain. A comparison based on seizure type was also looked at, but numbers were small. Fifteen of 27 (55.6%) focal onset patients and 3 of 5 (60%) patients with primary generalized onset experienced weight gain. Interestingly, 8 of the 9 patients with features of both focal and generalized onset demonstrated weight gain. Patients with weight gain were on a mean VPA dose of 1791 mg/day, compared to 1429 mg/day in patients without weight gain., Weight gain occurred in 63.4% of patients receiving VPA, although only 53.7% demonstrated weight gain by the end of the study. The mean maximum weight gained was 19% of initial body weight. Mean time to maximum weight was 44.2 months. Weight gain was more likely in male patients and patients on higher dosages of VPA. No significant difference was noted in focal onset versus primary generalized, although numbers for the latter were small. Interestingly, 88.9% of patients with features of both focal onset and primary generalized epilepsy (unclear onset) demonstrated weight gain.,