Study May Herald Change In Treatment for Parkinson's Disease
May 17, 2000 -- The treatment of Parkinson's disease may be about to undergo
a dramatic shift, particularly for people who are diagnosed with the condition
in their 30s and 40s. A new study has found that the drug Requip is far less
likely to cause the abnormal twisting and flailing movements that are a common
side effect of levodopa, the drug now used to treat the disease.
The study, published in the New England Journal of Medicine, is being
heralded by experts on the disease as extraordinarily important.
"Of the 50,000 people newly diagnosed with the disease, almost 30,000
will be candidates for going on an agonist [such as Requip] first," Abraham
Lieberman, MD, medical director of the National Parkinson Foundation, said at a
conference announcing the results of the study.
Requip, known generically as ropinirole, is one of a class of drugs called
"dopamine agonists." Dopamine is a chemical produced in the brain that
controls movement. People with Parkinson's disease lack sufficient dopamine,
which is why they have tremors in their arms and legs, walk slowly, and have
rigid muscles. Dopamine agonists are drugs that work like dopamine in the
Levodopa, which is sometimes called L-dopa, also acts like dopamine, but
because of the way it's converted in the brain, it eventually works for shorter
and shorter periods of time. The short bursts, or cycles, of stimulation
eventually cause severe involuntary movements known as dyskinesia. The problem
can become so severe that the drug must be discontinued, and the person is
It's estimated that 75% to 80% of people taking levodopa have side effects.
For many, the last resort for treating their disease is brain surgery, which is
expensive and has complications of its own.
To compare the two drugs, nearly 300 people age 30 and up with early
Parkinson's disease were studied for five years at 30 medical centers in
Europe, Israel, and Canada. All required medication to control their
Neither doctors nor the patients knew whether they were taking Requip or
levodopa. However, if their symptoms worsened and levodopa supplements were
necessary, the patients were told so.
Remarkably, more than half of the participants completed the study.
Two-thirds of those taking Requip required levodopa supplementation during the
course of the study, and one-third of those in the levodopa group needed more
of the drug. The number of people who had to drop out of the study early
because of side effects, such as nausea and hallucinations, was nearly equal in
the two groups.
While the symptoms of Parkinson's were equally well controlled by both
drugs, the important finding is that only about one in five of the patients
taking Requip developed dyskinesia, while nearly half of those in the levodopa
group did after five years.