Analysis finds side effects, loss of effectiveness over time
MONDAY, May 12 (HealthDay News) -- The drugs that are widely used to treat restless legs syndrome do provide relief, but they are burdened by side effects and a gradual loss of effectiveness that causes many sufferers to stop taking them, a new analysis finds.
"One of the things that we found that we can't fully explain is that they have more robust effects early in therapy," said study co-author C. Michael White, an associate professor of pharmacy practice at the University of Connecticut School of Pharmacy. The report was published in the May/June issue of the Annals of Family Medicine.
White and his colleagues looked at 14 trials of four nonergot dopamine agonist (NEDA) drugs, one of which never reached the market. The other three, pramipexole (Mirapex), ropinirole (Requip) and rotigotine (Neupro) are the mainstays of treatment for a condition that affects 5 percent to 10 percent of American adults.
"This kind of meta-analysis hasn't been done before," White said. "There have been lots of studies to assess their effects, but they didn't look at things like rates of withdrawal and risks associated with using the therapy."
Restless legs syndrome is a neurological disorder in which the leading symptom is described by its name. Those symptoms usually occur at night, interfering with sleep. NEDA drugs quiet the legs by mimicking the activity of dopamine, a molecule that acts as a hormone and also a signal transmitter between cells. Such drugs are also used to treat Parkinson's disease.
One drug that looked good in the meta-analysis was sumanirole, whose development was stopped in 2004 by Pfizer Inc. on the grounds that it offered no apparent advantage over existing medications. The meta-analysis included just one short-term study of sumanirole.
Among the others, White said, "when you look at the benefits of pramipexole,
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