The main treatment for Parkinson’s disease (given with a decarboxylase inhibitor)
Levodopa
The most effective medicine for the movement symptoms of Parkinson’s disease — it replaces the brain’s missing dopamine, and is always combined with a second drug that helps it reach the brain.
What is Levodopa?
Levodopa is the most effective treatment for the slowness, stiffness and tremor of Parkinson’s disease. The brain converts it into dopamine, the chemical messenger that is lost in Parkinson’s. It is always given combined with a second ingredient (carbidopa or benserazide) that stops it being broken down before it reaches the brain, reducing sickness. Over years its effect can become less smooth, causing "wearing off" and involuntary movements.
Education and reference only. This is a plain-language guide to Levodopa — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Levodopa is the cornerstone treatment for Parkinson’s disease and the most effective medicine for its movement symptoms. In Parkinson’s, the brain cells that make dopamine are lost; levodopa is the building block the brain uses to make dopamine, so it replaces what is missing. It is never given alone — it is always combined with a "decarboxylase inhibitor" (carbidopa in co-careldopa, or benserazide in co-beneldopa) that prevents it being broken down in the body before it reaches the brain, which both improves its effect and greatly reduces nausea. It is taken as tablets or capsules, in regular doses through the day.
How it works
The movement symptoms of Parkinson’s come from a shortage of dopamine in the brain. Dopamine itself cannot be given as a medicine because it does not cross from the blood into the brain — but levodopa can. Once in the brain, levodopa is converted into dopamine, restoring the signalling that controls smooth movement. The added carbidopa or benserazide blocks this same conversion in the rest of the body (where it would cause side effects and waste the drug), so more levodopa reaches the brain.
What it treats
Conditions Levodopa is used for
Practical use
How to take Levodopa
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it at regular, consistent times through the day — keeping to the schedule matters, especially as Parkinson’s progresses.
- Never stop it suddenly; abruptly stopping can cause a serious reaction. Any change is made gradually with your specialist.
- A very high-protein meal can reduce its absorption, so some people take it before food or separate it from large protein meals.
- Report involuntary movements, "wearing off" before the next dose, dizziness on standing, or any new impulse-control changes (e.g. gambling) to your team.
- Tell any prescriber you take it, and carry information about your Parkinson’s medicines in case of hospital admission.
Weighing it up
Advantages & disadvantages of Levodopa
Advantages
- The most effective medicine for the movement symptoms of Parkinson’s.
- The added ingredient greatly reduces nausea and improves how much reaches the brain.
- Available in standard, slow-release and dispersible forms to suit different needs.
Disadvantages
- With years of use its effect becomes less smooth — "wearing off" and involuntary movements.
- Timing around food and doses becomes increasingly important.
- Can cause nausea, low blood pressure on standing, and (from dopamine effects) impulse-control or hallucination problems.
Practical use
Good to know
Levodopa works remarkably well, especially in the early years. Over time, as Parkinson’s progresses, its effect can become less even: doses may "wear off" before the next is due, and higher levels can cause involuntary writhing movements (dyskinesia) — so timing becomes important, and treatment is fine-tuned. Take it at regular, consistent times; a large protein-rich meal can slow its absorption, so some people separate it from big protein meals. It should never be stopped suddenly, as this can cause a dangerous reaction. Nausea, low blood pressure on standing, and sometimes vivid dreams or impulse-control changes can occur.
Who should not take it / use with caution
- People with certain types of glaucoma, or a suspicious undiagnosed skin lesion (melanoma risk), need specialist assessment.
- People taking a non-selective MAOI antidepressant (a washout is needed), and used with care in significant heart, psychiatric or peptic-ulcer disease.
- It is used cautiously and individually in pregnancy and breastfeeding.
Monitoring
- Movement symptoms and response through the day
- Blood pressure (standing)
- Mood, hallucinations and impulse-control behaviours
Side effects
- Common early on: nausea (much reduced by the combined form), low blood pressure on standing (dizziness), and vivid dreams.
- With longer use: involuntary movements (dyskinesia) and fluctuations in the response ("on/off", "wearing off").
- Sometimes hallucinations or confusion, and impulse-control problems (such as gambling or compulsive behaviours) — report these.
Key interactions
- Non-selective MAOI antidepressants must not be combined (risk of a dangerous blood-pressure surge) — a washout gap is needed.
- Some anti-sickness and antipsychotic medicines that block dopamine can reduce its effect or worsen Parkinson’s — domperidone is the usual anti-sickness choice.
- Iron supplements and large protein meals can reduce its absorption if taken at the same time.
Available as: Tablets and capsules (co-careldopa / co-beneldopa), including slow-release and dispersible forms; also a gel given via a pump in advanced disease.
Answers
Levodopa: frequently asked questions
Why is levodopa combined with another drug?
On its own, most levodopa would be converted to dopamine in the body before reaching the brain, causing nausea and wasting the dose. The added carbidopa or benserazide blocks that conversion outside the brain, so more levodopa gets through and there is far less sickness — which is why it is always given as a combination (co-careldopa or co-beneldopa).
What is "wearing off"?
As Parkinson’s progresses, a dose of levodopa may stop working before the next one is due, so symptoms return between doses. This "wearing off", along with involuntary movements when levels are high, is why doses and timing are adjusted over time and why keeping to your schedule matters.
Should I take it with food?
A large protein-rich meal can slow levodopa’s absorption and make it less effective, so some people take it around 30–60 minutes before meals or separate it from big protein meals. If nausea is a problem, a small snack can help. Your specialist nurse can advise on the timing that works best for you.
Can I stop levodopa if I feel well or have side effects?
Never stop it suddenly — abruptly stopping levodopa can cause a serious, potentially dangerous reaction. If side effects are troubling you, contact your Parkinson’s team, who can adjust the timing, amount or form rather than you stopping on your own.
The wider class
About Levodopa (Parkinson’s)
Levodopa belongs to the levodopa (parkinson’s) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF: Co-careldopa; Co-beneldopa (levodopa).
- electronic Medicines Compendium (SmPC): Sinemet; Madopar.
- NICE NG71: Parkinson’s disease in adults.
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