Description

Simple

A medication used to treat Parkinson's Disease and other related conditions that affect body movement.

Clinical

A dopa decarboxylase inhibitor used in combination with levodopa for the symptomatic treatment of idiopathic Parkinson disease and other conditions associated with parkinsonian symptoms.

Overview

Carbidopa presents a chemical denomination of N-amino-alpha-methyl-3-hydroxy-L-tyrosine monohydrate. It potently inhibits aromatic amino acid decarboxylase (DDC) and due to its chemical properties, it does not cross the blood-brain barrier. Due to its activity, carbidopa is always administered concomitantly with [levodopa]. An individual formulation containing solely carbidopa was generated to treat nausea in patients where the combination therapy [levodopa]/carbidopa is not efficient reducing nausea.[9]

The first approved product by the FDA containing only carbidopa was developed by Amerigens Pharmaceuticals Ltd and approved on 2014.[10] 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.[11]

Pharmacology

Indication

Carbidopa is indicated with [levodopa] for the treatment of symptoms of idiopathic Parkinson disease, postencephalitic parkinsonism and symptomatic parkinsonism followed by carbon monoxide or manganese intoxication.[FDA label]

The combination therapy is administered for the reduction of [levodopa... Read more

Pharmacodynamic

When 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 an increased amount of [levodopa] and [oxitriptan] available for transport to the central ne... Read more

Mechanism of action

Carbidopa is an inhibitor of the DDC which in order, inhibits the peripheral metabolism of levodopa.[ Read more

Absorption

When [levodopa]/carbidopa is administered orally, 40-70% of the administered dose is absorbed.[12] Once absorbed, carbidopa shows bioavailability of 58%.[ Read more

Protein binding

It is widely accepted that the protein binding of carbidopa is 76%. However, more studies are required or the presentation of the source of this information.

Volume of distribution

The volume of distribution reported for the combination therapy of carbidopa/[levodopa] is of 3.6 L/kg.[ Read more

Clearance

The reported clearance rate for the combination therapy of [levodopa]/carbidopa is 51.7 L/h.[ Read more

Half life

The reported half-life of carbidopa is of approximately 107 minutes.[ Read more

Route of elimination

In animal studies, 66% of the administered dose of carbidopa was eliminated via the urine while 11% was found in feces. These studies were performed in humans and it was observed a urine excretion covering 50% of the administered dose.[ Read more

Toxicity

The LD50 of carbidopa is reported to be in the rat of 4810 mg/kg.[MSDS] In animal studies, carbidopa showed no incidences on neoplasia and showed no effect on the fertility status and development.[FDA label]

No reports of overdosage have been registered with the carbidopa-only product. In the eve... Read more

Adverse Effects

Contraindications

  • Hypersensitivity:
    • true
  • Regions: US
  • Regions: US
  • With Categories:
      • Name: Monoamine Oxidase Inhibitors
      • Drugbank Id: DBCAT001004
      • Mesh Id: D008996
  • Regions: US
  • Patient Conditions:
      • Name: Narrow-angle glaucoma
      • Drugbank Id: DBCOND0095646

Food Interactions

    Information currently not available.

Interactions

Type in a drug name to check for interaction with Carbidopa
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
Abacavir
Carbidopa may decrease the excretion rate of Abacavir which could result in a higher serum level.
Acarbose
Carbidopa may decrease the excretion rate of Acarbose which could result in a higher serum level.
Acebutolol
The risk or severity of hypotension can be increased when Carbidopa is combined with Acebutolol.
Aceclofenac
Aceclofenac may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Acemetacin
Acemetacin may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Acetaminophen
Carbidopa may decrease the excretion rate of Acetaminophen which could result in a higher serum level.
Acetazolamide
Acetazolamide may increase the excretion rate of Carbidopa which could result in a lower serum level and potentially a reduction in efficacy.
Acetylsalicylic acid
Acetylsalicylic acid may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Aclidinium
Carbidopa may decrease the excretion rate of Aclidinium which could result in a higher serum level.
Acrivastine
Carbidopa may decrease the excretion rate of Acrivastine which could result in a higher serum level.
Acyclovir
Acyclovir may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Adefovir
Adefovir may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Adefovir dipivoxil
Adefovir dipivoxil may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Albutrepenonacog alfa
Carbidopa may decrease the excretion rate of Albutrepenonacog alfa which could result in a higher serum level.
Alclofenac
Alclofenac may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Aldesleukin
Aldesleukin may decrease the excretion rate of Carbidopa which could result in a higher serum level.
Aliskiren
The risk or severity of hypotension can be increased when Carbidopa is combined with Aliskiren.
Allopurinol
Carbidopa may decrease the excretion rate of Allopurinol which could result in a higher serum level.
Allylestrenol
Carbidopa may decrease the excretion rate of Allylestrenol which could result in a higher serum level.
Almasilate
Carbidopa may decrease the excretion rate of Almasilate which could result in a higher serum level.
12 References
  1. 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: 4150141
  2. 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: 804550
  3. 3 . Mittur A, Gupta S, Modi NB: Pharmacokinetics of Rytary((R)), An Extended-Release Capsule Formulation of Carbidopa-Levodopa. Clin Pharmacokinet. 2017 Sep;56(9):999-1014. doi: 10.1007/s40262-017-0511-y.PubMed: 28236251
  4. 4 . 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: 11106255
  5. 5 . Yeh KC, August TF, Bush DF, Lasseter KC, Musson DG, Schwartz S, Smith ME, Titus DC: Pharmacokinetics and bioavailability of Sinemet CR: a summary of human studies. Neurology. 1989 Nov;39(11 Suppl 2):25-38.PubMed: 2685649
  6. 6 . Nyholm D, Lewander T, Gomes-Trolin C, Backstrom T, Panagiotidis G, Ehrnebo M, Nystrom C, Aquilonius SM: Pharmacokinetics of levodopa/carbidopa microtablets versus levodopa/benserazide and levodopa/carbidopa in healthy volunteers. Clin Neuropharmacol. 2012 May-Jun;35(3):111-7. doi: 10.1097/WNF.0b013e31825645d1.PubMed: 22549097
  7. 7 . Chana P, Fierro A, Reyes-Parada M, Saez-Briones P: [Pharmacokinetic comparison of Sinemet and Grifoparkin (levodopa/carbidopa 250/25 mg) in Parkinson s disease: a single dose study]. Rev Med Chil. 2003 Jun;131(6):623-31.PubMed: 12942590
  8. 8 . Rang, H. P. and Dale, M. M. (2012). Rang and Dale's Pharmacology (7th ed.). Edinburgh: Elsevier/Churchill Livingstone.
  9. 9 . Ahlskog J. (2009). Parkinson's disease treatment guide for physicians. Oxford University Press.
  10. 10 . FDA approvals Link
  11. 11 . FDA approvals Link
  12. 12 . Glown Link