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Accession NumberDB00190  (APRD00160)
TypeSmall Molecule

An inhibitor of DOPA decarboxylase, preventing conversion of levodopa to dopamine. It is used in parkinson disease to reduce peripheral adverse effects of levodopa. It has no antiparkinson actions by itself. [PubChem]

(-)-L-alpha-Hydrazino-3,4-dihydroxy-alpha-methylhydrocinnamic acid monohydrateNot AvailableNot Available
(2S)-3-(3,4-Dihydroxyphenyl)-2-hydrazinyl-2-methylpropanoic acid hydrateNot AvailableNot Available
(2S)-3-(3,4-Dihydroxyphenyl)-2-hydrazinyl-2-methylpropanoic acid monohydrateNot AvailableNot Available
(AlphaS)-alpha-hydrazino-3,4-dihydroxy-alpha-methylbenzenepropanoic acid monohydrateNot AvailableNot Available
(S)-(-)-Carbidopa hydrateNot AvailableNot Available
(S)-(−)-carbidopa hydrateNot AvailableNot Available
(S)-carbidopa hydrateNot AvailableNot Available
carbidopa hydrateNot AvailableNot Available
Carbidopa monohydrateNot AvailableNot Available
Carbidopum monohydricumNot AvailableNot Available
L-alpha-(3,4-Dihydroxybenzyl)-alpha-hydrazinopropionic acid monohydrateNot AvailableNot Available
Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Carbidopatablet25 mgoralOceanside Pharmaceuticals2014-04-04Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lodosyntablet25 mgoralKAISER FOUNDATION HOSPITALS2012-09-25Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lodosyntablet25 mgoralAton Pharma, Inc2010-04-13Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Carbidopatablet25 mgoralAmerigen Pharmaceuticals Inc.2013-11-01Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet, extended release25 mgoralREMEDYREPACK INC.2013-03-25Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet10 mgoralREMEDYREPACK INC.2013-10-07Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet10 mgoralREMEDYREPACK INC.2013-03-28Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet25 mgoralREMEDYREPACK INC.2013-02-27Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet25 mgoralREMEDYREPACK INC.2013-03-15Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet10 mgoralREMEDYREPACK INC.2013-02-22Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Carbidopa and Levodopatablet25 mgoralREMEDYREPACK INC.2013-03-25Not applicableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Over the Counter ProductsNot Available
International BrandsNot Available
Brand mixtures
Apo-levocarb - Tab 10mg/100mgApotex Inc
Apo-levocarb - Tab 25mg/250mgApotex Inc
Apo-levocarb CRApotex Inc
Apo-levocarb-tab 25mg/100mgApotex Inc
Carbidopa and LevodopaTeva Pharmaceuticals USA Inc
Carbidopa, Levodopa and EntacaponeMylan Pharmaceuticals Inc.
Carbidopa, Levodopa, and EntacaponeSandoz Inc
Dom-levo-carbidopaDominion Pharmacal
DuodopaAbbvie Corporation
DuopaAbb Vie Inc.
Nu-levocarb - Tab 10mg/100mgNu Pharm Inc
Nu-levocarb - Tab 25 Mg/100 mgNu Pharm Inc
Nu-levocarb - Tablets 25 Mg/250 mgNu Pharm Inc
ParcopaJazz Pharmaceuticals, Inc.
PMS-levocarb CRPharmascience Inc
Pro-lecarb-100/10 - TabPro Doc Limitee
Pro-lecarb-100/25 - TabPro Doc Limitee
Pro-levocarb - 100/25Pro Doc Limitee
Ratio-levodopa/carbidopaRatiopharm Inc Division Of Teva Canada Limited
RytaryImpax Laboratories, Inc.
SinemetMerck Sharp & Dohme Corp.
Sinemet 100/10Merck Canada Inc
Sinemet 100/25Merck Canada Inc
Sinemet 250/25Merck Canada Inc
Sinemet CRMerck Sharp & Dohme Corp.
Sinemet CR 100/25Merck Canada Inc
Sinemet CR 200/50Merck Canada Inc
StalevoNovartis Pharmaceuticals Corporation
Teva-levocarbidopaTeva Canada Limited
SaltsNot Available
CAS number28860-95-9
WeightAverage: 244.2444
Monoisotopic: 244.105921632
Chemical FormulaC10H16N2O5
(2S)-3-(3,4-dihydroxyphenyl)-2-hydrazinyl-2-methylpropanoic acid hydrate
DescriptionThis compound belongs to the class of organic compounds known as catecholamines and derivatives. These are compounds containing 4-(2-Aminoethyl)pyrocatechol [4-(2-aminoethyl)benzene-1,2-diol] or a derivative thereof formed by substitution.
KingdomOrganic compounds
Super ClassBenzenoids
ClassBenzene and substituted derivatives
Sub ClassPhenols and derivatives
Direct ParentCatecholamines and derivatives
Alternative Parents
  • 3-phenylpropanoic-acid
  • Catecholamine
  • Amphetamine or derivatives
  • Alpha-amino acid or derivatives
  • N-substituted-alpha-amino acid
  • Phenylpropane
  • Amino fatty acid
  • Fatty acyl
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboxylic acid derivative
  • Hydrocarbon derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Hydrazine derivative
  • Carbonyl group
  • Aromatic homomonocyclic compound
Molecular FrameworkAromatic homomonocyclic compounds
External Descriptors
IndicationFor treatment of the symptoms of idiopathic Parkinson's disease (paralysis agitans), post-encephalitic parkinsonism
PharmacodynamicsCarbidopa, a noncompetitive decarboxylase inhibitor, is used in combination with levodopa for the treatment of Parkinson's disease.
Mechanism of actionWhen mixed with levodopa, carbidopa inhibits the peripheral conversion of levodopa to dopamine and the decarboxylation of oxitriptan to serotonin by aromatic L-amino acid decarboxylase. This results in increased amount of levodopa and oxitriptan available for transport to the CNS. Carbidopa also inhibits the metabolism of levodopa in the GI tract, thus, increasing the bioavailability of levodopa.
AbsorptionRapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system.
Volume of distributionNot Available
Protein binding76%

The loss of the hydrazine functional group (probably as molecular nitrogen) represents the major metabolic pathway for carbidopa. There are several metabolites of carbidopa metabolism including 3-(3,4-dihydroxyphenyl)-2-methylpropionic acid, 3-(4-hydroxy-3-methoxyphenyl)-2-methylpropionic acid, 3-(3-hydroxyphenyl)-2-methylpropionic acid, 3-(4-hydroxy-3-methoxyphenyl)-2-methyllactic acid, 3-(3-hydroxyphenyl)-2-methyllactic acid, and 3,4-dihydroxyphenylacetone (1,2). [PMID: 4150141]

Not Available
Not Available
3-(3-hydroxyphenyl)-2-methyllactic acidDetails
Not Available
3-(3-hydroxyphenyl)-2-methylpropionic acidDetails
Not Available
3-(3,4-dihydroxyphenyl)-2-methylpropionic acidDetails
Not Available
3-(4-hydroxy-3-methoxyphenyl)-2-methyllactic acidDetails
Not Available
3-(4-hydroxy-3-methoxyphenyl)-2-methylpropionic acidDetails
Route of eliminationIn clinical pharmacologic studies, simultaneous administration of separate tablets of carbidopa and levodopa produced greater urinary excretion of levodopa in proportion to the excretion of dopamine when compared to the two drugs administered at separate times.
Half life1-2 hours
ClearanceNot Available
ToxicitySymptoms of a carbidopa toxicity include muscle spasms or weakness, spasms of the eyelid, nausea, vomiting, diarrhea, an irregular heartbeat, confusion, agitation, hallucinations, and unconsciousness.
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
Predicted ADMET features
Human Intestinal Absorption+0.8638
Blood Brain Barrier-0.9659
Caco-2 permeable-0.7517
P-glycoprotein substrateSubstrate0.5584
P-glycoprotein inhibitor INon-inhibitor0.9619
P-glycoprotein inhibitor IINon-inhibitor0.9952
Renal organic cation transporterNon-inhibitor0.9484
CYP450 2C9 substrateNon-substrate0.7843
CYP450 2D6 substrateNon-substrate0.8017
CYP450 3A4 substrateNon-substrate0.6267
CYP450 1A2 substrateInhibitor0.9106
CYP450 2C9 substrateNon-inhibitor0.9071
CYP450 2D6 substrateNon-inhibitor0.9231
CYP450 2C19 substrateNon-inhibitor0.9025
CYP450 3A4 substrateNon-inhibitor0.8308
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.9615
Ames testAMES toxic0.9107
BiodegradationNot ready biodegradable0.9741
Rat acute toxicity2.0520 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.9868
hERG inhibition (predictor II)Non-inhibitor0.9413
  • Aton pharma inc
Dosage forms
Tabletoral10 mg
Tabletoral25 mg
Tabletoral10 mg
Tablet, extended releaseoral25 mg
Tablet, orally disintegratingoral10; 100 mg/1; mg
Tablet, orally disintegratingoral25; 100 mg/1; mg
Tablet, orally disintegratingoral25; 250 mg/1; mg
Tablet, film coatedoral100; 200; 25 mg/1; mg/1; mg
Tablet, film coatedoral12.5; 200; 50 mg/1; mg/1; mg
Tablet, film coatedoral125; 200; 31.25 mg/1; mg/1; mg
Tablet, film coatedoral150; 200; 37.5 mg/1; mg/1; mg
Tablet, film coatedoral18.75; 200; 75 mg/1; mg/1; mg
Tablet, film coatedoral200; 200; 50 mg/1; mg/1; mg
Tablet, film coatedoral25; 200; 100 mg/1; mg/1; mg
Tablet, film coatedoral31.25; 200; 125 mg/1; mg/1; mg
Tablet, film coatedoral37.5; 200; 150 mg/1; mg/1; mg
Tablet, film coatedoral50; 200; 12.5 mg/1; mg/1; mg
Tablet, film coatedoral75; 200; 18.75 mg/1; mg/1; mg
Gelintraintestinal (upper)5 mg
Suspensionenteral20; 4.63 mg/mL; mg/mL
Tabletoral25 mg
Capsuleoral145; 36.25 mg/1; mg
Capsuleoral195; 48.75 mg/1; mg
Capsuleoral245; 61.25 mg/1; mg
Capsule, extended releaseoral95; 23.75 mg/1; mg
Tabletoral10; 100 mg/1; mg
Tabletoral25; 100 mg/1; mg
Tabletoral25; 250 mg/1; mg
Tablet, extended releaseoral25; 100 mg/1; mg
Tablet, extended releaseoral50; 200 mg/1; mg
Tablet (extended-release)oral25 mg
Tablet (extended-release)oral50 mg
Tabletoral200 mg
Tablet, film coatedoral12.5; 50; 200 mg/1; mg/1; mg
Tablet, film coatedoral18.75; 75; 200 mg/1; mg/1; mg
Tablet, film coatedoral25; 100; 200 mg/1; mg/1; mg
Tablet, film coatedoral31.25; 125; 200 mg/1; mg/1; mg
Tablet, film coatedoral37.5; 150; 200 mg/1; mg/1; mg
Tablet, film coatedoral50; 200; 200 mg/1; mg/1; mg
Unit descriptionCostUnit
Carbidopa powder27.54USD g
Lodosyn 25 mg tablet2.53USD tablet
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
PatentsNot Available
Experimental Properties
melting point208 °CPhysProp
water solubility3.8 mg/LNot Available
logP-1.9Not Available
Predicted Properties
pKa (Strongest Acidic)3.59ChemAxon
pKa (Strongest Basic)5.65ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count6ChemAxon
Hydrogen Donor Count5ChemAxon
Polar Surface Area115.81 Å2ChemAxon
Rotatable Bond Count4ChemAxon
Refractivity68.77 m3·mol-1ChemAxon
Polarizability21.81 Å3ChemAxon
Number of Rings1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Mass Spec (NIST)Not Available
SpectraNot Available
Synthesis Reference


General Reference
  1. Vickers S, Stuart EK, Bianchine JR, Hucker HB, Jaffe ME, Rhodes RE, Vandenheuvel WJ: Metabolism of carbidopa (1-(-)-alpha-hydrazino-3,4-dihydroxy-alpha-methylhydrocinnamic acid monohydrate), an aromatic amino acid decarboxylase inhibitor, in the rat, rhesus monkey, and man. Drug Metab Dispos. 1974 Jan-Feb;2(1):9-22. Pubmed
  2. Vickers S, Stuart EK, Hucker HB: Further studies on the metabolism of carbidopa, (minus)-L-alpha-hydrazino-3,4-dihydroxy-alpha-methylbenzenepropanoic acid monohydrate, in the human, Rhesus monkey, dog, and rat. J Med Chem. 1975 Feb;18(2):134-8. Pubmed
External Links
ATC CodesNot Available
AHFS CodesNot Available
PDB Entries
FDA labelNot Available
MSDSDownload (73.4 KB)
Drug Interactions
DroxidopaCarbidopa may diminish the therapeutic effect of Droxidopa. Carbidopa may decrease serum concentrations of the active metabolite(s) of Droxidopa. Carbidopa may increase the serum concentration of Droxidopa.
Food InteractionsNot Available


1. Aromatic-L-amino-acid decarboxylase

Kind: protein

Organism: Human

Pharmacological action: yes

Actions: inhibitor


Name UniProt ID Details
Aromatic-L-amino-acid decarboxylase P20711 Details


  1. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. Pubmed
  2. Durso R, Evans JE, Josephs E, Szabo G, Evans B, Fernandez HH, Browne TR: Variable absorption of carbidopa affects both peripheral and central levodopa metabolism. J Clin Pharmacol. 2000 Aug;40(8):854-60. Pubmed
  3. Yee RE, Cheng DW, Huang SC, Namavari M, Satyamurthy N, Barrio JR: Blood-brain barrier and neuronal membrane transport of 6-[18F]fluoro-L-DOPA. Biochem Pharmacol. 2001 Nov 15;62(10):1409-15. Pubmed
  4. Kaufmann H, Saadia D, Voustianiouk A, Goldstein DS, Holmes C, Yahr MD, Nardin R, Freeman R: Norepinephrine precursor therapy in neurogenic orthostatic hypotension. Circulation. 2003 Aug 12;108(6):724-8. Epub 2003 Jul 28. Pubmed
  5. Orlefors H, Sundin A, Lu L, Oberg K, Langstrom B, Eriksson B, Bergstrom M: Carbidopa pretreatment improves image interpretation and visualisation of carcinoid tumours with 11C-5-hydroxytryptophan positron emission tomography. Eur J Nucl Med Mol Imaging. 2006 Jan;33(1):60-5. Epub 2005 Sep 24. Pubmed
  6. Calabrese V, Mancuso C, Ravagna A, Perluigi M, Cini C, De Marco C, Butterfield DA, Stella AM: In vivo induction of heat shock proteins in the substantia nigra following L-DOPA administration is associated with increased activity of mitochondrial complex I and nitrosative stress in rats: regulation by glutathione redox state. J Neurochem. 2007 May;101(3):709-17. Epub 2007 Jan 4. Pubmed
  7. Gilbert JA, Frederick LM, Ames MM: The aromatic-L-amino acid decarboxylase inhibitor carbidopa is selectively cytotoxic to human pulmonary carcinoid and small cell lung carcinoma cells. Clin Cancer Res. 2000 Nov;6(11):4365-72. Pubmed

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Drug created on June 13, 2005 07:24 / Updated on September 24, 2013 16:39