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Systematic (IUPAC) name
Clinical data
Trade names Comtan (single ingredient), Stalevo (multi-ingredient)
AHFS/Drugs.com monograph
MedlinePlus a601236
Licence data US Daily Med:link
  • AU: B3
  • US: C (Risk not ruled out)
Legal status
Routes of
Pharmacokinetic data
Bioavailability 35%
Protein binding 98% (binds to serum albumin)
Metabolism Hepatic
Biological half-life 0.4-0.7 hour
Excretion Faeces (90%), Urine (10%)
CAS Registry Number 130929-57-6 YesY
ATC code N04BX02
PubChem CID: 5281081
DrugBank DB00494 YesY
ChemSpider 4444537 YesY
UNII 4975G9NM6T YesY
KEGG D00781 YesY
Chemical data
Formula C14H15N3O5
Molecular mass 305.286 g/mol
 YesY (what is this?)  (verify)

Entacapone (INN) (/ˌɛntəkəˈpn/ or /ɛnˈtækəpn/) is a drug that functions as a catechol-O-methyl transferase (COMT) inhibitor. It is used in the treatment of Parkinson's disease.

When administered in conjunction with dopaminergic agents such as L-DOPA, entacapone prevents COMT from metabolizing L-DOPA into 3-methoxy-4-hydroxy-L-phenylalanine (3-OMD) in the periphery, which does not easily cross the blood–brain barrier (BBB). Pharmacologically, entacapone is somewhat similar to carbidopa or benserazide, in that it is an inhibitor of an enzyme that converts L-DOPA into a compound that cannot cross the blood–brain barrier. Carbidopa and benserazide inhibit aromatic L-amino acid decarboxylase, which converts L-DOPA into dopamine, which cannot cross the blood–brain barrier.

Entacapone is a member of the class of drugs known as nitrocatechols.

Side effects[edit]

The most frequent undesirable effects caused by entacapone relate to the increased effects of L-DOPA, such as involuntary movements (dyskinesias). These occur most frequently at the beginning of entacapone treatment. Others common side effects are gastrointestinal problems, including nausea and abdominal pains. Diarrhea is a frequently reported and troublesome side effect that can result in unnecessary investigation, but resolves quickly on withdrawal of the drug.[1] Entacapone may cause urine to turn reddish-brown. This is a harmless side effect and is not a cause for concern. In studies with entacapone, some people have reported experiencing a dry mouth.


Entacapone is developed by Orion Pharma and marketed by Novartis under the trade name COMTan in the United States.

Stalevo is another medication developed by Orion Pharma and marketed by Novartis that contains entacapone in combination with carbidopa and levodopa (active ingredients in Sinemet).


  1. ^ Singer C (2002). "Adverse effects in the treatment of Parkinson’s disease". Expert Review of Neurotherapeutics 2 (1): 105–118. doi:10.1586/14737175.2.1.105. 

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