What is the typical starting dose of sinemet (carbidopa and levodopa) for a patient with parkinsons? How long do you need to take it feel its effects? Several weeks?

Varies. Different movement disorder neurologists have varying treatment regimens, but i prefer to start sinemet (carbidopa and levodopa) at low dosing initially, such as 10/100 3-4 times daily in divided dosing. With your dbs, the regimen may require a different plan.