Levodopa
A dopamine precursor, given with carbidopa or benserazide, that the brain turns into dopamine to ease Parkinson's disease.
Also called L-dopa (abbreviation), co-careldopa (UK name for levodopa with carbidopa) or co-beneldopa (UK name for levodopa with benserazide).
Drug card
- Class
- Dopamine precursor
- How it works
- Supplying levodopa, which the brain converts into dopamine
- Used for
- Parkinson's disease
- Parkinsonism after encephalitis or poisoning
- Known for
- Involuntary movements (dyskinesia)
- Wearing-off and on-off swings
- Its name
- -dopa means a dopamine-related drug (levodopa type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does levodopa work?
A prodrug: levodopa crosses the blood-brain barrier and DOPA decarboxylase in the brain converts it to dopamine. It is always combined with carbidopa or benserazide, decarboxylase inhibitors that cannot enter the brain; they stop levodopa turning into dopamine in the gut and blood, so more of each dose reaches the brain and nausea and vomiting are reduced.
Uses
What is levodopa used for?
- Parkinson's disease
- Parkinsonism after encephalitis or poisoning
Side effects
Side effects of levodopa
- Involuntary movements (dyskinesia)Known for
- Wearing-off and on-off swingsKnown for
- Nausea and vomiting
- Dizziness on standing (orthostatic hypotension)
- Hallucinations and psychosisSerious
- Falling asleep suddenly during daily activitiesSerious
- Compulsive gambling, spending or eatingSerious
- Fever, rigidity and confusion if stopped suddenlySerious
- Stomach bleeding in people with a past ulcerSerious
- Raised eye pressure in glaucomaSerious
- Dark urine, saliva or sweat
- Melanoma (link to the drug unclear)Serious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Non-selective MAO inhibitors (phenelzine) are contraindicated: stop them at least 2 weeks before, or blood pressure can rise.
- Stopping it suddenly can cause a reaction like neuroleptic malignant syndrome, so the dose is tapered.
- Dopamine blockers (metoclopramide, antipsychotics) and iron salts weaken its effect.
- Pyridoxine (vitamin B6) speeds the breakdown of levodopa given alone; carbidopa cancels this.
Good to know: It eases the symptoms but does not slow the disease; as more dopamine neurons are lost, each dose wears off sooner.
Remember it
A way to remember it
Levodopa travels with a bodyguard.
Carbidopa (or benserazide) guards levodopa in the blood so it is not turned into dopamine before it reaches the brain; the guard itself stays outside the brain.
Written for biofideX
Its name
-dopa means dopamine-related drug (levodopa type)
Levodopa is turned into dopamine in the brain, while methyldopa, with the same ending, lowers blood pressure through a metabolite that stimulates central alpha-2 receptors.
- Every drug name stem
Its class
Dopamine precursors
Levodopa, the amino acid from which dopamine is made, crosses the blood-brain barrier and DOPA decarboxylase in the brain converts it to dopamine, making up for the dopamine lost in Parkinson's disease and easing slowness, stiffness and tremor. A peripheral decarboxylase inhibitor (carbidopa or benserazide) that stays out of the brain is always added, so less levodopa becomes dopamine before it arrives.
Easily mixed up with dopamine agonists and MAO-B inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Carbidopa and levodopa tablets: label (DailyMed)
- Carbidopa and levodopa extended-release capsules: label (DailyMed)
- Levodopa (NCI Thesaurus)
- Carbidopa (NCI Thesaurus)
- Co-beneldopa (NHS)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Parkinson's, dementia and migraine
Levodopa is one of 9 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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