My mom (75 years old but biologically younger) has early parkinson's. any downside to mao-b inhibitor instead of levodopa if symptoms minimal?

Neurologist can help: A small amount of information is on the internet regarding MAO inhibitors (such as selegiline) and l-dopa to treat parkinson's. Among elderly patients, individuals can react quite differently to various meds & doses, so a person's treatment has to be customized. It appears that using both meds allows one to use a lower dose of l-dopa. The list of selegiline side effects looks milder than l-dopa's.

NO, it's preferred!!: Dopamine meds are mainstay of treatment. Modern therapy recommends longer lasting, milder potency meds first: Azilect (mao-b selective inhibitor) & Dopamine agonists (requip xl/mirapex er/neupro). After they've been maximized & stronger meds ate needed to adequately manage symptoms, then sinemet +/- Comtan (stalevo (carbidopa and levodopa and entacapone) is both together) are begun. Tailor rx with side effects in mind for each person.