Abstracts

Rationale: The use of pregabalin (PGB) has been associated with weight gain. The mechanisms mediating this adverse event are yet to be established. The purpose of this study is to investigate variables associated with weight gain during treatment with PGB for epilepsy, including gender, dosing, treatment duration, baseline body mass index (BMI) and concomitant use of anticonvulsant drugs (AEDs) with appetite neutral, suppressant or stimulant properties.Methods: This is a retrospective chart review study of 25 serially selected patients on PGB at a comprehensive epilepsy center. Patient weight, BMI, PGB dose and concomitant AEDs from each visit were recorded. Length of follow-up, change in weight and BMI classification, maximum dose and mg/kg of PGB were calculated. Patients were grouped into being on concomitant AEDs with either appetite neutral (lamotrigine, carbamazepine, levetiracetam), appetite suppressant (topiramate, zonisamide) or appetite stimulant (valproic acid) properties. Patients on appetite suppressant or stimulant AEDs were further subdivided into groups either remaining on these AEDs while PGB was added versus patients who were tapered off the appetite effective medication. Results: Data from 16 females and 9 males were reviewed. The mean age of the sample was 37.8 (± 12.9) years and the mean duration of treatment with PGB was 9.9 (± 4.9) months. Baseline BMI classifications for the sample were as follows: 3 patients were classified as underweight, 11 were classified as normal, 7 were overweight and 4 were classified as obese. At follow-up, this pattern changed with 1 underweight, 9 normal, 4 overweight, 9 obese and 2 extremely obese. This change in distribution of BMI classification was due to an overall mean increase of 17.3 (± 12.2) pounds in weight. To assess variables associated with this weight change, baseline weight, duration of follow-up, age, PGB mg/kg, and concomitant use of AEDs with appetite suppressant or appetite stimulant properties were entered into a multiple regression as predictor variables with weight change as the outcome variable. The only significant predictor variable that entered the model was concomitant use of AEDs with appetite suppressant properties (F[1,23] 5.9, p < .03). Examination of the group means revealed that patients who had discontinued appetite suppressant AEDs following administration of PGB suffered greater weight gain than patients who either remained on, or did not receive appetite suppressant or stimulant AEDs.Conclusions: Patients who are tapered off appetite suppressant AEDs while treated with PGB appear to be at risk for significantly higher weight gain compared to patients who remained on AEDs with either appetite suppressant, neutral or stimulant properties. The cause of this weight gain may be primarily due to change in appetite following PGB treatment, rebound from tapering off appetite suppressant AEDs, or a combination of these effects. Regardless of cause, increased weight may not only lead to significant health problems but may also effect patient compliance for PGB treatment.