New research presented Tuesday shows that a relatively new drug for treating Parkinson's disease produces less of a debilitating side effect than the most widely prescribed drug used for the disorder.
Dr. Oliver Rascol of the Centre Hospitalier Universitaire, Toulouse, France, presented the study at a medical conference in Vancouver, British Columbia.
The study compared the widely used levadopa with the newer drug Requip, made by SmithKline Beecham, which has its U.S. headquarters in Philadelphia. Requip was approved by the federal government just two years ago while levadopa, also known as Sinemet, has been available for 35 years and is given to 75 percent of patients.
Levadopa is the most effective treatment for the symptoms of Parkinson's, which include tremors, slow movement, rigidity and poor balance. But it has a side effect -- involuntary body movements.
For most patients, this is mostly a social embarrassment. But in some patients, "it can be even more troublesome, preventing you from being able to eat or to sit up in a chair," Rascol said.
An expert not involved in the study agreed.
"Some of the longer-term complications are much more difficult to manage...and can be as disabling as the disease itself," said Dr. Matthew B. Stern, director of the Parkinson's Disease and Movement Disorders Center at the University of Pennsylvania.
Requip is one of a promising new class of drugs called dopamine agonists. They still have side effects, including confusion, upset stomach, lightheadedness, hallucinations and sleepiness, but they are not as disabling as the involuntary body movements, Stern said.
The five-year study shows that treating patients with Requip at the outset, and using levadopa only when Parkinson's symptoms become bad enough to require the stronger drug, resulted in fewer involuntary body movements than the common treatment of using levadopa from the beginning.
"You can delay the levadopa and you can use lower doses of levadopa," Rascol said. In a minority of cases, no levadopa is needed at all, he said.
Previous studies supported a similar conclusion, but Rascol's study had more reliable conclusions than earlier ones, Stern said.
For one thing, this study selected the patients early on and tracked them throughout their treatments. Also, this was a "double-blind" study in which neither the patients nor the people tracking the symptoms knew which drugs were in use.
According to SmithKline Beecham, 130 people completed the study, 85 on Requip and 45 on levadopa. Among those given Requip, 27 percent suffered side effects, compared with 29 percent of those on levadopa.
However, the incidence of uncontrollable body movements was 5 percent for Requip and 36 percent for levadopa.
Written By Dan Robrish