Efficacy Study of Betahistine on Body Weight in Obese Female Subjects

This is a randomized, double-blind, placebo-controlled, dose finding, multicenter study. The study will consist of 3 treatment groups (48 mg/day, 96 mg/day, and matching placebo). Approximately 180 subjects (60 per treatment group) will be randomized into this 12-week study. A screening visit will be used to determine subject suitability for inclusion in the trial. One week after the screening visit subjects who meet all inclusion criteria and none of the exclusion criteria will be randomly assigned to 1 of the following treatment groups: * Betahistine 24 mg twice a day (BID) (48 mg/day total), * Betahistine 48 mg BID (96 mg/day total), * Matching placebo. All subjects will be prescribed a nutritionally balanced mildly hypocaloric diet. The prescribed diet will contain approximately 30% of calories from fat, 50% of calories from carbohydrates, and 20% of calories from protein. The individual subject's estimated total daily energy expenditure minus 600 kcal will be used to determine each subject's daily caloric intake value during the study. The total daily energy expenditure will be estimated for each subject from the basal energy expenditure multiplied by a correction factor of 1.3 to account for the amount of energy needed in mild to moderate daily activity for obese subjects. Double-blind treatment will continue for 12 weeks. Study medication (betahistine and/or matching placebo) will be orally administered BID about 1-2 hrs prior to meals (at 10:00 and at 17:00). During this period, 4 additional study visits (at 2, 4, 8, and 12 weeks) will take place.