Carbidopa
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Carbidopa
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| Systematic (IUPAC) name | |
| (2S)-3-(3,4-dihydroxyphenyl)-2-hydrazino-2-methylpropanoic acid | |
| Identifiers | |
| CAS number | |
| ATC code | ? |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C10H14N2O4 |
| Mol. mass | 226.229 g/mol |
| SMILES | & |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Protein binding | 76% |
| Metabolism | decarboxylated to dopamine in extracerebral tissues |
| Half life | 2 hours |
| Excretion | ? |
| Therapeutic considerations | |
| Licence data | |
| Pregnancy cat. |
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| Legal status | |
| Routes | ? |
Carbidopa (sold as Lodosyn) is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa.
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[edit] Pharmacology
Carbidopa inhibits aromatic-L-amino-acid decarboxylase (DOPA Decarboxylase or DDC),[1] an enzyme important in the biosynthesis of L-tryptophan to serotonin and in the biosynthesis of L-DOPA to Dopamine (DA).
Along with carbidopa, other DDC inhibitors are benserazide (Ro-4-4602), difluromethyldopa, and α-methyldopa.
[edit] Uses
Used in tandem with L-DOPA (trade name levodopa, a dopamine precursor converted in the body to dopamine), it increases the plasma half-life of levodopa from 50 minutes to 1 1/2 hours. CarbiDOPA cannot cross the blood brain barrier, so it inhibits only peripheral DDC. It thus prevents the conversion of L-DOPA to dopamine peripherally. This reduces the side effects caused by dopamine on the periphery, as well as increasing the concentration of L-DOPA and dopamine in the brain.
The combination of carbidopa/levodopa) carries the brand names of Sinemet, Parcopa and Atamet; whilst Stalevo is a combination with entacapone, which enhances the bioavailability of carbidopa and levodopa.
Carbidopa is also used in combination with 5-HTP, a naturally occurring amino acid which is a precursor to the neurotransmitter serotonin and an intermediate in tryptophan metabolism. Carbidopa prevents 5-HTP's metabolism in the liver, which can lead to elevated levels of serotonin in the bloodstream. Research shows that co-administration of 5-HTP and carbidopa greatly increases plasma 5-HTP levels. Without the use of carbidopa, there is a significant risk of heart valve disease when taking 5-HTP, due to serotonin's affect on the heart.[2][3] In Europe, 5-HTP is prescribed with carbidopa to prevent the conversion of 5-HTP into serotonin until it reaches the brain.[4]
[edit] References
- ^ Gilbert JA, Frederick LM, Ames MM (November 2000). "The aromatic-L-amino acid decarboxylase inhibitor carbidopa is selectively cytotoxic to human pulmonary carcinoid and small cell lung carcinoma cells". Clinical cancer research : an official journal of the American Association for Cancer Research 6 (11): 4365–72. PMID 11106255. http://clincancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=11106255.
- ^ Gustafsson BI, Tømmerås K, Nordrum I, Loennechen JP, Brunsvik A, Solligård E, Fossmark R, Bakke I, Syversen U, Waldum H (March 2005). "Long-term serotonin administration induces heart valve disease in rats". Circulation 111 (12): 1517–22. doi:. PMID 15781732.
- ^ Xu J, Jian B, Chu R, Lu Z, Li Q, Dunlop J, Rosenzweig-Lipson S, McGonigle P, Levy RJ, Liang B (December 2002). "Serotonin mechanisms in heart valve disease II: the 5-HT2 receptor and its signaling pathway in aortic valve interstitial cells". Am. J. Pathol. 161 (6): 2209–18. PMID 12466135. PMC: 1850896. http://ajp.amjpathol.org/cgi/content/abstract/161/6/2209.
- ^ http://www3.interscience.wiley.com/journal/119498636/abstract?CRETRY=1&SRETRY=0
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