Key takeaways
Sinemet (carbidopa/levodopa) and Stalevo (carbidopa/levodopa/entacapone) are both used to treat Parkinson's disease (PD) symptoms like shakiness and slowed movement. Sinemet combines carbidopa and levodopa, while Stalevo adds a third ingredient, entacapone. The addition of entacapone in Stalevo helps levodopa stay in your body longer, reducing "off" periods when symptoms return. Sinemet is available in immediate-release, extended-release, and orally disintegrating tablets, whereas Stalevo is only available in an immediate-release tablet. Both medications can cause sleepiness and dark-colored bodily fluids, but Stalevo can cause diarrhea that may last awhile. Sinemet is often a first-choice treatment, while Stalevo is useful if you need longer-lasting symptom relief. Both medications are available in lower-cost generic versions.
