Carbidopa 25mg tablets
Requires a prescription from a doctor or prescriber
Carbidopa presents a chemical denomination of N-amino-alpha-methyl-3-hydroxy-L-tyrosine monohydrate.
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MHRA alerts for Carbidopa
Safety monitoring data
Yellow Card reports
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Suspected adverse reactions reported for Carbidopa
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Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
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Suspected adverse reactions reported for Carbidopa
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1 branded products available
NHS prescribing volume and spending trends
Guidelines from the National Institute for Health and Care Excellence
NICE clinical guidance(2)
Foslevodopa–foscarbidopa for treating advanced Parkinson's with motor symptoms (TA934)
Parkinson's disease in adults (NG71)
Source: National Institute for Health and Care Excellence (NICE). Contains public sector information licensed under the Open Government Licence v3.0.
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Supply & safety information
Official UK regulator monitoring and safety alerts
Pharmacy links redirect to the retailer's own search and do not represent real-time stock levels. Shortage and safety information sourced from MHRA drug safety updates (gov.uk, Crown Copyright under OGL v3.0).
Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0.
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Academic studies and reviews for this medicine's active substance
Showing the 50 most relevant studies.
Reviews & meta-analyses: 18 · Randomised trials: 12 · 1999–2026
Showing the 50 most relevant studies, sorted by most relevant.
R. Hauser, A. Hsu, S. Kell, et al.
The Lancet. Neurology, 2013
Rinaldi D, De Carolis L, Ledda C, et al.
2026
Background/Objectives: Non-motor symptoms (NMS) are highly prevalent in advanced Parkinson's disease (PD) and substantially affect quality of life. Continuous infusion therapies are established treatment options for motor fluctuations not controlled by oral medication, but their effects on NMS remain incompletely characterized. We aimed to evaluate the effects of continuous infusion therapies on NMS in advanced PD. Methods: A systematic review was conducted according to PRISMA guidelines. PubMed, Embase, and Cochrane were searched for English-language original studies published between January 2005 and 1 March 2026. Eligible studies included patients with PD treated with levodopa-carbidopa intestinal gel (LCIG), continuous subcutaneous apomorphine infusion (CSAI), subcutaneous levodopa formulations, or levodopa-entacapone-carbidopa intestinal gel (LECIG) and reported quantitative NMS outcomes. Due to methodological heterogeneity, results were synthesized qualitatively. Results: Fifty-four studies were included. Most evaluated LCIG (n = 38), followed by CSAI (n = 14), subcutaneous levodopa formulations (n = 6), and LECIG (n = 2). Overall, 4157 patients were assessed at baseline and 2919 at follow-up. Global non-motor burden improved in 33/45 (73.3%) baseline-to-follow-up comparisons. NMSS total score decreased from 84.4 ± 35.2 to 54.9 ± 17.6. The most consistent benefits were observed for sleep/fatigue and gastrointestinal symptoms. Sleep/fatigue outcomes improved in 26/31 (83.9%) baseline-to-follow-up comparisons. Cognitive outcomes were mostly stable, while cardiovascular, urinary, sexual, and mood-specific outcomes showed less consistent benefit. Conclusions: Continuous infusion therapies may be associated with reduced global non-motor burden in advanced PD, particularly sleep/fatigue and gastrointestinal symptoms. Evidence is strongest for LCIG, while data for CSAI, LECIG, and subcutaneous levodopa formulations remain limited.
Abstract licence: CC BY
Libo Wang, Jia Li, Jiajun Chen
Frontiers in Neurology, 2018
A. Espay, Fabrizio Stocchi, Rajesh Pahwa, et al.
The Lancet. Neurology, 2024
R. Hauser, A. Espay, A. Ellenbogen, et al.
JAMA Neurology, 2023
H. Baishya
Journal of Developing Drugs, 2017
A. Antonini, W. Poewe, K. Chaudhuri, et al.
Parkinsonism & related disorders, 2017
E. Freire-Álvarez, E. Kurča, L. López Manzanares, et al.
Movement Disorders, 2021
R. Pahwa, K. Lyons, R. Hauser, et al.
Parkinsonism & related disorders, 2014
Antonini A, Bergmans B, Kern DS, et al.
2026
IntroductionWe evaluated continuous subcutaneously administered foslevodopa/foscarbidopa (LDp/CDp) in younger patients earlier within advanced Parkinson's disease (aPD).MethodsThis phase 3 trial included patients aged ≥ 30 years with levodopa-responsive PD, Mini-Mental State Examination score ≥ 24, and levodopa equivalent dose ≥ 400 mg/day. Patients were considered by the investigator as inadequately controlled on current oral/transdermal therapy and experienced ≥ 2.5 h/day "Off" time, with recognizable "On"/"Off" states. Patients were randomized (1:1) to LDp/CDp plus placebo capsules or orally administered immediate-release levodopa/carbidopa plus placebo infusion. This post hoc exploratory analysis focused on younger patients (≤ 65 years) earlier within aPD (Hoehn and Yahr stage ≤ 2 ["On" state], ≤ 5 years since motor fluctuations started). Outcomes included change from baseline (CFB) to week 12 in "Off" and "On" time, Movement Disorder Society Unified PD Rating Scale (MDS-UPDRS) II, 39-item PD Questionnaire (PDQ-39), and PD Sleep Scale-2 (PDSS-2).ResultsTwenty-six patients met subgroup criteria (LDp/CDp, n = 13; orally administered levodopa/carbidopa, n = 13). Despite small sample sizes, at week 12, LDp/CDp was associated with significantly greater improvements in "Off" time (mean [SD] CFB - 3.7 [3.1] vs - 1.6 [2.9] h; P = 0.0011), "On" time without troublesome dyskinesia (+ 3.9 [3.3] vs + 1.4 [3.8] h; P = 0.0011), and PDSS-2 (- 6.4 [4.6] vs - 1.8 [3.1]; P = 0.0220) vs orally administered levodopa/carbidopa. Mean (SD) CFB to week 12 (LDp/CDp vs orally administered levodopa/carbidopa) was + 4.2 (2.8) vs + 1.9 (4.6) h for "On" time without dyskinesia (P = 0.0878), - 3.0 (6.4) vs - 0.9 (3.5) for MDS-UPDRS II (P = 0.3539), and - 9.9 (7.4) vs - 1.9 (9.4) for PDQ-39 (P = 0.0534). For most assessments, treatment differences were numerically larger in the subgroup vs the overall population. Safety findings were consistent with the overall population.ConclusionsLDp/CDp was associated with significantly greater improvements in motor function and sleep vs orally administered levodopa/carbidopa in younger patients earlier within aPD whose symptoms were inadequately controlled by oral/transdermal therapies. Larger real-world studies are needed to confirm findings.Trial registrationClinicalTrials.gov identifier, NCT04380142.
Abstract licence: CC BY-NC
Sources: aggregated from Europe PMC (EMBL-EBI), OpenAlex, Crossref, PubMed and other open scholarly databases. Retracted articles are excluded. Study information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
173 found
Half-life
107 minutes
Mechanism
Carbidopa is an inhibitor of the DDC which in order, inhibits the peripheral metabolism of levodopa.
Food interactions
None known
Human targets
1 target
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
40-70%
[L5116]
…
Half-life
107 minutes
[A173944]
Protein binding
76%
Volume of distribution
3.6 L/kg
Metabolism
Elimination
66%
Clearance
51.7 L/h
[A173947]
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
The first approved product by the FDA containing only carbidopa was developed by Amerigens Pharmaceuticals Ltd and approved on 2014.[L5110] On the other hand, the combination treatment of carbidopa/levodopa was originally developed by Watson Labs but the historical information by the FDA brings back to the approval of this combination therapy developed by Mayne Pharma in 1992.[L5113]
The combination therapy is administered for the reduction of [levodopa]-driven nausea and vomiting.[FDA label]
The product of carbidopa should be used in patients where the combination therapy of carbidopa/[levodopa] provide less than the adequate daily dosage.[FDA label]
As well carbidopa can be used in patients where the dosages of carbidopa and [levodopa] require individual titration.[FDA label]
Known interactions with other medicines. Always consult a healthcare professional.
Showing 50 of 942 interactions
No reports of overdosage have been registered with the carbidopa-only product. In the event of overdosage, immediate gastric lavage is recommended as well as intravenous fluid administration. Continuous electrocardiographic monitoring is required.[FDA label]
DDC can be found in the body periphery and in the blood-brain barrier.[A13607] The action of carbidopa is focused on peripheral DDC as this drug cannot cross the blood-brain barrier.[T28] Hence, it will prevent the metabolism of [levodopa] in the periphery but it will not have any activity on the generation of dopamine in the brain.
The presence of additional units of circulating [levodopa] can increase the effectiveness of the still functional dopaminergic neurons and it has been shown to alleviate symptoms for a time. The action of carbidopa is very important as [levodopa] is able to cross the blood-brain barrier while dopamine cannot.[T28] Hence the administration of carbidopa is essential to prevent the transformation of external [levodopa] to dopamine before reaching the main action site in the brain.
The coadministration of carbidopa with [levodopa] has been shown to increase the half-life of [levodopa] more than 1.5 times while increasing the plasma level and decreasing clearance. The combination therapy has also shown an increase of the recovery of [levodopa] in urine instead of dopamine which proves a reduced metabolism. This effect has been highly observed by a significant reduction in [levodopa] requirements and a significant reduction in the presence of side effects such as nausea. It has been observed that the effect of carbidopa is not dose-dependent.[T394]
How the body processes this drug — absorption, distribution, metabolism, and elimination
[L5116]
Once absorbed, carbidopa shows bioavailability of 58%.
[A173941]
A maximum concentration of 0.085 mcg/ml was achieved after 143 min with an AUC of 19.28 mcg.min/ml.
[A173944]
[A173944]
[A173947]
However, carbidopa is widely distributed in the tissues, except in the brain.
[L5116]
After one hour, carbidopa is found mainly in the kidney, lungs, small intestine and liver.
[A274]
[A274]
[A274]
[A173947]
Proteins and enzymes this drug interacts with in the body
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
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Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Carbidopa
Additional database identifiers
Drugs Product Database (DPD)
2370
ChemSpider
31640
BindingDB
50418773
PDB
142
ZINC
ZINC000019168887
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2719
GenAtlas
DDC
GeneCards
DDC
GenBank Gene Database
M76180
GenBank Protein Database
181521
UniProt Accession
DDC_HUMAN
DrugBank citations
If you use DrugBank data in your research, please cite:
- DrugBank 6.02024Recommended citationKnox C., Wilson M., Klinger C.M., et alDrugBank 6.0: the DrugBank Knowledgebase for 2024Nucleic Acids Res. 2024 Jan 552(D1):D1265-D1275
- DrugBank 5.02018Wishart D.S., Feunang Y.D., Guo A.C., et alDrugBank 5.0: a major update to the DrugBank database for 2018Nucleic Acids Res. 2017 Nov 846(D1):D1074-D1082
- DrugBank 4.02014Law V., Knox C., Djoumbou Y., et alDrugBank 4.0: shedding new light on drug metabolismNucleic Acids Res. 2014 Jan 142(1):D1091-7
- DrugBank 3.02011Knox C., Law V., Jewison T., et alDrugBank 3.0: a comprehensive resource for 'omics' research on drugsNucleic Acids Res. 2011 Jan39(Database issue):D1035-41
- DrugBank 2.02008Wishart D.S., Knox C., Guo A.C., et alDrugBank: a knowledgebase for drugs, drug actions and drug targets.Nucleic Acids Research2008 Jan36(Database issue):D901-6
- DrugBank 1.02006Wishart D.S., Knox C., Guo A.C., et alDrugBank: a comprehensive resource for in silico drug discovery and exploration.Nucleic Acids Research2006 Jan 134(Database issue):D668-72