Researchers hope a drug used to treat Parkinson's disease will help put a major medical cause of insomnia to rest.
A study published in the August issue of the journal Sleep has found that the drug, ropinirole, can bring relief to people suffering from a condition known as Restless Legs Syndrome.
About 10 percent of the general U.S. population have the neurological disorder, researchers say. About 80 percent of them suffer from uncomfortable feelings that cause their legs to twitch as they try to sleep.
Dr. Richard Allen, a neurologist at Johns Hopkins Bayview Medical Center in Baltimore, is one of the authors of the 12-week study. Allen said the condition is a significant cause of insomnia.
"These are dramatically effective treatments for what remains an unmet medical need in our society," he said.
People with the condition can take 30 minutes to an hour to get to sleep, Allen said, but the medicine reduced that time down to about 8 or 10 minutes.
"It also increased the sleep time, so they're getting about a half an hour more of sleep a night, which may not sound like a lot, but that's a significant benefit on average," Allen said.
The report was the largest placebo-controlled published sleep study evaluation of any treatment for the condition. It found that patients woke up less in the middle of the night when treated with GlaxoSmithKline's Requip (ropinirole).
Sixty-five patients with at least a moderately severe form of the condition took part in the study, which included a placebo controlled, parallel study at 15 research centers nationwide.
The 32 patients randomly assigned to receive ropinirole had a mean age of 55 years and 63 percent were women.
Fifty-five patients completed the study, including 28 of 32 in the ropinirole group and 27 of 33 in the placebo group.
Involuntary leg movements decreased from 49 per hour to 12 per hour in the group treated with Requip, the study found. That compared with a decrease of 36 kicks each hour to 34 in the placebo group.
"The study indicates that the use of Requip produces a dramatic reduction in abnormal leg movements during sleep and results in improved sleep quality, allowing people to then function better on their next day," said Philip Becker, president of Sleep Medicine Associates of Texas.
While ropinirole is used to treat Parkinson's disease, the study found that much less dosages of the drug were needed to treat Restless Legs Syndrome. A mean dose of 1.8 mg per day reduced the periodic leg movements to normal levels. A pill is taken an hour or two before bed.
Requip is under review by the Food and Drug Administration for the treatment of the condition.
Patients between 18 to 79 were used in the study. The condition can affect people of all ages, but it tends to worsen in people over the age of 50. Women suffer from the condition more than men at a ratio of about 2 to 1.
Although the underlying cause of the condition remains unknown, research points to mild alterations in dopamine regulation in the brains of patients.
Requip stimulates post-synaptic dopamine receptors in the brain.
Allen said he hoped the drug could go on the market next year to treat Restless Legs Syndrome.
Researchers reported no serious side effects from the drug. The most common reported with Requip versus placebo were headaches (34.4 percent vs. 18.2), nausea (31.3 vs. 15.2) and dizziness (18.8 vs. 3 percent), according to the study.
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