Sinemet: profile and news

Fraser speaks out about Parkinson’s Apr 21, 2006
...s disease. Steenson takes Sinemet and Mirapex and his doses are slowly being increased to help him keep the disease at bay. He said ... - Campbell River Mirror,

Other information

Indication
For the treatment of idiopathic Parkinson's disease (Paralysis Agitans), postencephalitic parkinsonism, symptomatic parkinsonism which may follow injury to the nervous system by carbon monoxide intoxication, and manganese intoxication.

Pharmacology
Levodopa (L-dopa) is used to replace dopamine lost in Parkinson's disease because dopamine itself cannot cross the blood-brain barrier where its precursor can. However, L-DOPA is converted to dopamine in the periphery as well as in the CNS, so it is administered with a peripheral DDC (dopamine decarboxylase) inhibitor such as carbidopa, without which 90% is metabolised in the gut wall, and with a COMT inhibitor if possible; this prevents about a 5% loss. The form given therapeutically is therefore a prodrug which avoids decarboxylation in the stomach and periphery, can cross the blood-brain barrier, and once in the brain is converted to the neurotransmitter dopamine by the enzyme aromatic-L-amino-acid decarboxylase.

Mechanism Of Action
Striatal dopamine levels in symptomatic Parkinson's disease are decreased by 60 to 80%, striatal dopaminergic neurotransmission may be enhanced by exogenous supplementation of dopamine through administration of dopamine's precursor, levodopa. A small percentage of each levodopa dose crosses the blood-brain barrier and is decarboxylated to dopamine. This newly formed dopamine then is available to stimulate dopaminergic receptors, thus compensating for the depleted supply of endogenous dopamine.

Drug Category
Dopamine Agents; Antiparkinson Agents; Antidyskinetics; ATC:N04BA01; ATC:N04BA04

Brand Names/Synonyms
Atamet; Bendopa; Brocadopa; Cidandopa; DA; DOPA; Deadopa; Dopaflex; Dopaidan; Dopal; Dopal-Fher; Dopalina; Dopar; Doparkine; Doparl; Dopasol; Dopaston; Dopastral; Doprin; Eldopal; Eldopar; Eldopatec; Eurodopa; Helfo-Dopa; Insulamina; L-DOPA; L-Dihydroxyphenylalanine; L-Dopa; L-Dopa for Biochemistry 99+%; Laradopa; Larodopa; Ledopa; Levedopa; Levodopa; Levopa; Maipedopa; Parda; Pardopa; Prodopa; Sinemet; Sinemet Cr; Syndopa; Veldopa; Weldopa

Dosage Forms
Tablets, pink, scored, each containing levodopa 0.1 g

Absorption
Levodopa is rapidly absorbed from the proximal small intestine by the large neutral amino acid (LNAA) transport carrier system.

Interactions
Interactions for Levodopa:

No information provided.

Chemical IUPAC Name
2-amino-3-(3,4-dihydroxyphenyl)-propanoic acid

Chemical Formula
C9H11NO4

Half Life
50 to 90 minutes

Drug Type
Approved Drug

# Accession No
APRD00309

CAS Registry Number
59-92-7