The FDA has approved entacapone (COMTAN, Orion Corp, Scotch Plains, NJ), a new catechol-O-methyltransferase (COMT) inhibitor, as an adjunct to levodopa/carbidopa for patients with Parkinson disease who experience end-of-dose worsening. Entacapone's ability to inhibit COMT, one of the enzymes responsible for the metabolism of dopamine, results in greater and more sustained plasma levels of dopamine than levodopa/carbidopa when the latter is given alone. One 200-mg entacapone tablet is administered concomitantly with each dose of levodopa/carbidopa, up to a maximum of 8 doses per day (1600 mg/d).
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