A method for effecting weight loss by administering a combination of topiramate and phentermine is provided. The phentermine is generally administered in immediate release form, in a daily dose in the range of 2 mg to 8 mg, in combination with a daily dose of topiramate selected to prevent the loss of effectiveness of phentermine alone. Methods for treating obesity, conditions associated with obesity, and other indications are also provided, as are compositions and dosage forms containing low doses of phentermine and topiramate,
