Carbidopa
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Carbidopa
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| Systematic (IUPAC) name | |
| (2S)-3-(3,4-dihydroxyphenyl)-2-hydrazinyl-2-methyl- propanoic acid |
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| Identifiers | |
| CAS number | |
| ATC code | ? |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C10H14N2O4 |
| Mol. mass | 226.229 g/mol |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Protein binding | 76% |
| Metabolism | decarboxylated to dopamine in extracerebral tissues |
| Half life | 2 hours |
| Excretion | ? |
| Therapeutic considerations | |
| Licence data |
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| Pregnancy cat. |
? |
| Legal status | |
| Routes | ? |
Carbidopa (MK-486, tradename Lodosyn) is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa.
Carbidopa inhibits aromatic-L-amino-acid decarboxylase (DOPA Decarboxylase or DDC), 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.
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.
