New research on levodopa's influence on Parkinson's progression

A clinical trial has produced further evidence that there is no benefit of delaying levodopa therapy.

Research published in the New England Journal of Medicine, suggests levodopa doesn't influence the progression of Parkinson's.

As part of a controlled trial carried out at the University of Amsterdam, 417 people with early Parkinson's were split into 2 groups:

  • half received levodopa in combination with carbidopa for 80 weeks
  • half received a placebo for 40 weeks and then levodopa in combination with carbidopa for 40 weeks

The researchers measured Parkinson's symptoms using the Unified Parkinson's Disease Rating Scale at various points in the trial in order to assess the progression of the condition.

At the end of the 80-week trial there was no significant difference between symptoms in those that had received the drug straight away and those that had the delayed start.

What is levodopa?

Levodopa is a common drug used to control symptoms in Parkinson's. It is a chemical building-block that your body converts into dopamine, replacing the dopamine that is lost in Parkinson's. It is often taken with a drug such as carbidopa to make sure as much levodopa as possible reaches the brain.

There is already evidence that levodopa, for most people, improves symptoms particularly related to movement. But there is some evidence linking long term levodopa therapy with side effects, such as involuntary movements called dyskinesia.

No effect on progression

In this new trial, after 40 weeks the researchers found that those on levodopa had improved symptoms compared with those on the placebo. But at the end of the trial there were no significant differences between the 2 groups and those who had taken levodopa for 80 weeks did not experience more side effects.

Dr Katherine Fletcher, our Research Communications Officer, says:

"Levodopa is an important tool for managing Parkinson's symptoms. But, there are outstanding research questions about how levodopa impacts the progression of Parkinson's and when people should start the treatment.

"This new research suggests that levodopa does not alter the progression of the condition within the tested timescale. More research into different doses and timescales would be needed to assess this further.

"If people are concerned about their Parkinson's medication – please seek healthcare advice."