Entacapone
Encyclopedia
Entacapone (icon or ɛ) is a drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

 that functions as a catechol-O-methyl transferase
Catechol-O-methyl transferase
Catechol-O-methyltransferase is one of several enzymes that degrade catecholamines such as dopamine, epinephrine, and norepinephrine. In humans, catechol-O-methyltransferase protein is encoded by the COMT gene...

 (COMT) inhibitor
COMT inhibitor
A COMT inhibitor is a drug that inhibits the action of catechol-O-methyl transferase. This enzyme is involved in degrading neurotransmitters. COMT inhibitors are used in the treatment of Parkinson's disease....

. It is used in the treatment of Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...

.

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
Carbidopa
Carbidopa is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa.- Pharmacology :...

 or benserazide
Benserazide
Benserazide is a peripherally-acting aromatic L-amino acid decarboxylase or DOPA decarboxylase inhibitor, which is unable to cross the blood-brain barrier.- Indications :...

, 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
Aromatic L-amino acid decarboxylase
Aromatic L-amino acid decarboxylase is a lyase enzyme.-Reactions:It catalyzes several different decarboxylation reactions:* L-DOPA to dopamine - a neurotransmitter* 5-HTP to serotonin - also a neurotransmitter...

, which converts L-DOPA into dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

, which cannot cross the blood brain barrier.

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

The most frequent undesirable effects caused by entacapone relate to the increased effects of L-DOPA, such as involuntary movements (dyskinesia
Dyskinesia
Dyskinesia is a movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements, similar to tics or choreia. Dyskinesia can be anything from a slight tremor of the hands to uncontrollable movement of, most commonly, the upper body but...

s). These occur most frequently at the beginning of entacapone treatment. Others common side effects are gastrointestinal
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

 problems, including diarrhoea, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

 and abdominal pains. The substance 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.

Products

Entacapone is developed by Orion Pharma and marketed by Novartis
Novartis
Novartis International AG is a multinational pharmaceutical company based in Basel, Switzerland, ranking number three in sales among the world-wide industry...

 under the trade name COMTan in the United States.

Stalevo
Stalevo
Stalevo is an anti-parkinsonian dopaminergic combination medication that contains carbidopa, levodopa, and entacapone for the treatment of Parkinson's disease...

 is another Novartis medication that contains entacapone in combination with carbidopa
Carbidopa
Carbidopa is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa.- Pharmacology :...

 and levodopa
Levodopa
L-DOPA is a chemical that is made and used as part of the normal biology of some animals and plants. Some animals including humans make it via biosynthesis from the amino acid L-tyrosine. L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine , and epinephrine collectively...

 (active ingredients in Sinemet).

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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