 Carbidopa/levodopa/entacapone was approved by the U.S. Food and Drug Administration (FDA) in June 2003, to treat adults with Parkinson's disease of unknown cause in two scenarios.First, to substitute with equivalent strength of each of the three components for immediate-release carbidopa/levodopa and entacapone previously administered as individual products.Second, to replace immediate-release carbidopa/levodopa therapy (without entacapone) when people experience the signs and symptoms of end-of-dose "wearing-off" but only for people taking a total daily dose of levodopa of 600 mg or less and not experiencing dyskinesias.