RLS can affect up to 12 million people in the United States. Recent research suggests it affects about 10 per cent of adults in Europe with rates increasing with age. Lower prevalence has been found in India, Japan and Singapore, indicating that racial or ethnic factors are associated with RLS.
Pramipexole, is a non-ergot agonist and while the exact mechanism of action is unknown, it is believed to help increase the release of certain neurological chemicals that improve control over movement.
The study, part of Boehringer Ingelheim's ongoing clinical development program into Restless Legs Syndrome, demonstrated that a once-daily dose regimen improved RLS symptoms for a 24-hour period. In the study pramipexole showed a rapid onset of action and produced significant improvements in patients' sleep.
Patients of at least 18 years of age with idiopathic Restless Legs Syndrome were randomised to treatment with pramipexole or placebo. Patients underwent a flexible dose titration phase during weeks one to four (dose range: 0.125mg to 0.75 mg daily). A total of 345 patients in five European countries received treatment. The mean age at RLS onset was 55.5 years and the mean duration of RLS was 5.2 years.
The results showed severity was significantly greater for the pramipexole group compared to the placebo group. Additionally, nearly two-thirds (62.9 per cent) of the patients treated with pramipexole were classified as responders (much or very much improved) compared to 32.5 per cent of the placebo patients.
Just under one-third of patients (30.6 per cent) treated with pramipexole showed a much or very much improved response after one week on the starting dose of just 0.125 mg per day compared to only 7.0 per cent receiving placebo.
"This is important for patients and physicians as they can expect a fast onset of action as well as a persistent response in some RLS patients maintained on the starting dose of just 0.125 mg," said Professor Wolfgang Oertel, chairman of the department of neurology centre of nervous diseases, Philipps University, Germany.
Restless Legs Syndrome is a neurological disorder characterised by an uncontrollable urge to move the legs, usually accompanied by unpleasant and sometimes painful sensations in the legs. Around one-third of sufferers experience symptoms more than twice weekly causing moderate to severe distress. The motor restlessness worsens during the evening and night causing difficulty initiating and maintaining sleep.
The results of this study indicate that Pramipexole may become a viable choice for a disorder that has suffered from an inability to determine exactly what causes RLS. Although many different drugs may help RLS, those most commonly used are found three categories
Benzodiazepines are central nervous system depressants that do not fully suppress RLS sensations or leg movements, but allow patients to obtain more sleep despite these problems. Some drugs in this group may result in daytime drowsiness. People with sleep apnea should not use benzodiazepines.
Dopaminergic agents are drugs used to treat Parkinson's disease and are also effective for many people with RLS. These medications have been shown to reduce RLS symptoms and nighttime leg movements.
Opioids are pain killing and relaxing drugs that can suppress RLS in some people. These medications can sometimes help people with severe, unrelenting symptoms.