Tolcapone

Tolcapone

Systematic (IUPAC) name
(3,4-dihydroxy-5-nitrophenyl)(4-methylphenyl)methanone
Clinical data
Trade names	Tasmar
AHFS/Drugs.com	monograph
MedlinePlus	a698036
Pregnancy cat.	C(US)
Legal status	℞-only (US)
Routes	Oral
Pharmacokinetic data
Bioavailability	65%
Protein binding	>99.9%
Half-life	2-3.5 hours
Identifiers
CAS number	134308-13-7
ATC code	N04BX01
PubChem	CID 4659569
DrugBank	APRD00445
ChemSpider	3848682 Y
UNII	CIF6334OLY Y
KEGG	D00786 Y
ChEMBL	CHEMBL1324 Y
Chemical data
Formula	C14H11NO5
Mol. mass	273.241 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C14H11NO5/c1-8-2-4-9(5-3-8)13(17)10-6-11(15(19)20)14(18)12(16)7-10/h2-7,16,18H,1H3 Y Key:MIQPIUSUKVNLNT-UHFFFAOYSA-N Y
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Tolcapone (tradename Tasmar) is a drug that inhibits the enzyme catechol-O-methyl transferase (COMT).

Uses

Tolcapone is used in the treatment of Parkinson's disease as an adjunct to levodopa/carbidopa medication.

Chemistry

Tolcapone is a yellow, odorless, non-hygroscopic, crystalline compound with a relative molecular mass of 273.25. The chemical name of tolcapone is 3,4-dihydroxy-4’-methyl-5-nitrobenzophenone. Its empirical formula is C₁₄H₁₁NO₅.

Pharmacology

Tolcapone has the ability to cross the blood-brain barrier and thus exerts its COMT inhibitory effects in the CNS as well as in the periphery.

Tolcapone has demonstrated significant hepatotoxicity that limits the drug's utility. Entacapone, another COMT inhibitor, is an alternative selection for L-DOPA adjunct therapy in the treatment of Parkinson's disease, largely since it has a more favorable toxicity profile.

Normally, administration of levodopa is compromised when COMT converts it to 3-methoxy-dopa. By preventing this effect, more of the levodopa that is administered reaches the CNS. Additionally, levodopa that is in the CNS, after being converted to dopamine, will not be degraded by COMT when tolcapone inhibits COMT activity.

See also

• Entacapone