"Common Drugs for Parkinson's Disease
Levodopa and carbidopa (Duopa, Rytary,Sinemet). Levodopa (also called L-dopa) is the most commonly prescribed medicine for Parkinson’s. It’s also the best at controlling the symptoms of the condition, particularly slow movements and stiff, rigid body parts.
Levodopa works when your brain cells change it into dopamine. That’s a chemical the brain uses to send signals that help you move your body. People with Parkinson’s don’t have enough dopamine in their brains to control their movements.
Sinemet is a mix of levodopa and another drug called carbidopa. Carbidopa makes the levodopa work better, so you can take less of it. That prevents many common side effects of levodopa, such as nausea, vomiting, and irregular heart rhythms."
https://www.webmd.com/parkinsons-disease/guide/drug-treatments#1