People with Parkinson’s disease who received zonisamide, in addition to levodopa and other anti-Parkinson’s medications had significantly reduced odds of developing dementia, gastric ulcers and insomnia. These results were compared with those who were given three of the seven non-levodopa drug classes. Zonisamide is currently indicated for the treatment of seizure disorder. The findings also associated zonisamide to a significantly lower likelihood of constipation, limb fracture and orthostatic hypotension but a higher risk of aspiration pneumonia and depression, compared with one or more of the other non-levodopa medications, which may make it an alternative choice in the treatment of Parkinson’s Disease.