Key takeaways
Selegiline (Zelapar) and Carbidopa (Lodosyn) are both used to help manage symptoms of Parkinson's disease (PD), but they work in different ways and have distinct characteristics. Selegiline is a monoamine oxidase type B (MAO-B) inhibitor that helps prevent the breakdown of dopamine in your brain, extending the effects of levodopa. It comes in tablets, capsules, and orally disintegrating tablets (ODTs), with the tablet and capsule forms available as lower-cost generics. Carbidopa, on the other hand, is a decarboxylase inhibitor that helps more levodopa reach your brain by preventing its breakdown before it gets there. Carbidopa must be taken with levodopa and is available in a lower-cost generic form. Selegiline can cause high blood pressure if you eat foods rich in tyramine, while Carbidopa can cause dark-colored bodily fluids and usually needs to be taken multiple times a day. Both medications can cause sleepiness, hallucinations, and changes in behavior, but Selegiline also has a risk of serotonin syndrome when taken with certain other medications.
