Tolcapone

Information about Tolcapone

Entacapone is a catechol-O-methyltransferase inhibitor used in the therapy of Parkinson disease as adjunctive therapy in combination with levodopa and carbidopa.  Entacapone has been associated with a low rate of serum enzyme elevations during treatment, but has yet to be implicated in cases of clinically apparent acute liver injury with jaundice. 

Mechanism of action of Tolcapone

Entacapone (en tak' a pone) is a specific inhibitor of cathechol-O-methyltransferase (COMT) which is a major enzyme in the pathway of levodopa metabolism.  As a result, entacapone slows the metabolism of levodopa, causing an increase in its bioavailability and duration of action.  Entacapone inhibits COMT activity only peripherally, unlike tolcapone which acts both peripherally and centrally. 

FDA approval information for Tolcapone

Entacapone was approved for use in the United States in 2003, the second COMT inhibitor approved for use in the therapy of symptomatic Parkinson disease as an adjunct to levodopa/carbidopa therapy in patients with motor complications. 

{[dose}} Entacapone is available in tablets of 200 mg generically and under the brand name of Comtan.  It is also available in several fixed dose combinations with carbidopa and levodopa generically and under the brand name Stalevo.  Entacapone is typically initiated in doses of 200 mg with each dose of levodopa/carbidopa to a maximum of 1600 mg daily. 

Side effects of Tolcapone

Common side effects include somnolence, dizziness, confusion, dyskinesia, vivid dreams, hallucinations, depression, fatigue, headache, diarrhea and gastrointestinal upset, side effects that are largely due to enhancement of the dopaminergic effects of levodopa.

• Dailymed label info on Tolcapone
• FDA Tolcapone

Tolcapone

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  Chemical structure of Tolcapone

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  3D model of Tolcapone

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  Tolcapone bound to COMT enzyme

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  COMT enzyme activity

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  Metabolism of Tolcapone

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  Synthesis of Tolcapone