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Comtan (ENTACAPONE)

Orion Pharma · FDA-approved approved Small molecule Quality 60/100

Comtan works by blocking the enzyme catechol-O-methyltransferase, which breaks down dopamine in the brain.

Comtan (Entacapone) is a small molecule catechol-O-methyltransferase inhibitor developed by Orion Pharma, currently owned by the same company. It was FDA approved in 1999 for the treatment of Parkinson's disease. As an off-patent medication, Comtan is available as a generic from multiple manufacturers. Key safety considerations include its short half-life of 2.4 hours and moderate bioavailability of 42%. Comtan is used in combination with levodopa and carbidopa to manage symptoms of Parkinson's disease.

At a glance

Generic nameENTACAPONE
SponsorOrion Pharma
Drug classCatechol-O-Methyltransferase Inhibitor [EPC]
TargetCatechol O-methyltransferase
ModalitySmall molecule
Therapeutic areaMetabolic
PhaseFDA-approved
First approval1999

Mechanism of action

Mechanism of Action. Entacapone is selective and reversible inhibitor of catechol-O-methyltransferase (COMT).In mammals, COMT is distributed throughout various organs with the highest activities in the liver and kidney. COMT also occurs in the heart, lung, smooth and skeletal muscles, intestinal tract, reproductive organs, various glands, adipose tissue, skin, blood cells, and neuronal tissues, especially in glial cells. COMT catalyzes the transfer of the methyl group of S-adenosyl-L-methionine to the phenolic group of substrates that contain catechol structure. Physiological substrates of COMT include dopa, catecholamines (dopamine, norepinephrine, and epinephrine) and their hydroxylated metabolites. The function of COMT is the elimination of biologically active catechols and some other hydroxylated metabolites. In the presence of decarboxylase inhibitor, COMT becomes the major metabolizing enzyme for levodopa, catalyzing the metabolism to 3-methoxy-4-hydroxy-L-phenylalanine (3-OMD) i

Approved indications

Common side effects

Key clinical trials

Primary sources

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SourceUsed for
FDA labelMechanism, indications, dosing, boxed warnings, drug interactions
ClinicalTrials.govTrial enrolment, design, endpoints, results