Intervention
gastrointestinal disorder
GASTROINTESTINAL DISORDER
During the observation period, levodopa/decarboxylase inhibitors were administered at ≤300 mg/day for 4 consecutive weeks, maintaining constant dosage and administration. This baseline treatment with levodopa was also maintained during the evaluation period at the same dosage and administration as during observation (At the end of the observation period, subjects were randomized to receive either zonisamide 25 mg/day in addition to levodopa (zonisamide add-on group) or an increased levodopa dose of 100 mg/day (100 mg once daily or 50 mg twice daily at the physician’s discretion) (levodopa increase group), and the timing of the administration was set at the physician’s discretion. Therefore, although this was an open-label study, the method of administration of the increased levodopa dose of 100 mg differed among patients. During the evaluation period, the study drug (zonisamide or levodopa) was administered orally for 24 weeks (zonisamide 25-mg tablets once daily in the morning). The final observation was made at the end of the study drug administration. Restricted concomitant medications included antihypertensive, central nervous system, cardiovascular, and gastrointestinal disorder drugs, and Chinese herbal preparations.