What is the difference between parkinson's drug sinemet and stalevo (carbidopa and levodopa and entacapone)?

COMT inhibitor: Entacaptone is a selective catecholamine-o methyl transferase (comt) inhibitor that increases the bioavailabilty of dopamine. Like Carbidopa in sinemet it does not cross the blood brain barrier. Stalevo (carbidopa and levodopa and entacapone) is a combination of l dopa, Carbidopa and entacaptone. Sinemet is a combination of Carbidopa and l-dopa.