New research findings show most doctors are prescribing levodopa as they should — when a patient needs it.
There's debate about when to start taking levodopa (Sinemet) for Parkinson's movement symptoms. Some people think starting the medication will bring on jerky movements associated with levodopa use (called dyskinesia) sooner, so they delay levodopa even if they have significant symptoms of tremor and stiffness.
Others have wondered if levodopa is slowing the disease process and they should start taking it early in their disease course. The brain turns levodopa into the neurotransmitter dopamine, which is lost in Parkinson's disease. Some studies questioned if that process improved disease even after stopping the medication.
Findings published this week in the New England Journal of Medicine showed neither was true. Levodopa use sooner didn't bring on greater dyskinesia, but it also didn't slow the course of disease.
"Basically, it confirms what we currently do," Susan Bressman, MD, told U.S. News and World Report. Bressman is co-director of the Mount Sinai Parkinson and Movement Disorders Center and co-author of an editorial accompanying the study.
"Most people don't start levodopa at first diagnosis, when they have hardly any symptoms, because they don't need it. We don't think the drug is protecting the brain, so we don't start it right away... But as soon as they do start to need it, we start it. We use it. And we're judicious in how we use it," she said.
Researchers at the University of Amsterdam in the Netherlands gave 222 people with early-stage Parkinson's disease levodopa for 80 weeks. Another group, of 223 people, got a placebo for 40 weeks then levodopa for 40 weeks. The participants, and their study physicians, did not know their assigned group to minimize placebo effect.
At the end of the 80 weeks, they found the groups very similar. The group that took levodopa for the first 40 weeks did not have slower disease progression, but they also did not have a faster rate of dyskinesia or symptom fluctuations.
"We couldn't really prove one way or the other if it's good or bad for the brain," Bressman said. "But the bottom line — people need it. We don't have a better drug. It's the most potent drug for the symptoms, so you've got to use it, but you don't use a high dose."
We are working on better drugs that will stop the disease process. Read about progress in therapies toward a leading target: LRRK2.
In the meantime, we're also working on new treatments to better control symptoms. The recently approved Inbrija — which received early funding from MJFF — helps quickly alleviate symptoms when oral levodopa wears off. Read more about that therapy and another that will receive word on market approval next week.
And hear from our movement disorder specialist, Rachel Dolhun, MD, on myths around levodopa and its use. Read her blog and watch your email inbox for a new video on this topic in her popular "Ask the MD" series.