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Levodopa / Carbidopa

Ross D. Zafonte, MD · FDA-approved active Small molecule

Levodopa is converted to dopamine in the brain to replace deficient neurotransmitter levels, while carbidopa inhibits premature conversion of levodopa in the periphery, allowing more to reach the brain.

Levodopa is converted to dopamine in the brain to replace deficient neurotransmitter levels, while carbidopa inhibits premature conversion of levodopa in the periphery, allowing more to reach the brain. Used for Parkinson's disease, Parkinsonism secondary to carbon monoxide poisoning or manganese intoxication.

At a glance

Generic nameLevodopa / Carbidopa
Also known asSinemet
SponsorRoss D. Zafonte, MD
Drug classDopamine precursor with peripheral decarboxylase inhibitor
TargetAromatic amino acid decarboxylase (AADC); dopamine pathway
ModalitySmall molecule
Therapeutic areaNeurology
PhaseFDA-approved

Mechanism of action

Levodopa is a precursor to dopamine that crosses the blood-brain barrier, where it is converted to dopamine by aromatic amino acid decarboxylase (AADC). Carbidopa is a decarboxylase inhibitor that does not cross the blood-brain barrier, so it blocks peripheral conversion of levodopa to dopamine, reducing side effects and increasing the amount of levodopa available for central nervous system conversion. This combination restores dopamine levels in Parkinson's disease patients.

Approved indications

Common side effects

Key clinical trials

Primary sources

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SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results