Pramipexole
Pramipexole is a remarkably interesting medicine about which you are likely to hear a lot in the near future. It is an agonist, which means that it has a positive effect, on D2 dopamine receptors and also on a little-known group of dopamine receptors, known as the D3 group. If you want to get really clever the dopamine receptor D3 group is abbreviated to DRD3. Pramipexole has been in use for almost a decade in the treatment of Parkinson’s disease, and approximately 9.1 million prescriptions for pramipexole have been written in the U.S. since its launch in 1997. It is not without its problems. In Parkinson’s disease it may cause dizziness, involuntary movement, hallucinations, headache, difficulty falling asleep, sleepiness, and nausea. Some people have also had behavioral dyscontrol while taking it.
At a meeting in Athens in February of 2006, we saw confirmation of something that had been shown in previous research: pramipexole seems to be a very effective treatment for restless legs syndrome (RLS). A study published in the journal Neurology has given us a more detailed understanding of the risks and benefits of pramipexole.
The investigators report a 12-week, multicenter, double-blind, randomized, placebo-controlled study of fixed daily doses of pramipexole (0.25 mg, 0.50 mg, and 0.75 mg) involving 344 patients with moderate to severe RLS. Data from 339 patients were analyzed to evaluate the effect of pramipexole treatment on efficacy and safety. The mean age of patients was 51.4 years and the mean duration of RLS symptoms was 5.1 years. The results were very promising, even though half of the patients on placebo also showed an improvement. The most commonly reported side effect included nausea (19.0%), headache (17.8%), insomnia (10.5%) and somnolence (10.1%).
In Europe pramipexole it has been approved for use in this indication. It is marketed as Sifrol® / Mirapexin® In the United States we currently only have one approved medical treatment for RLS, and that is the GlaxoSmithKline medicine ropinirole (Requip), that works at the same D3 receptors in the brain and spinal cord. Ropinirole is effective in a proportion of people with RLS, but it has also been linked to sleepiness, drops in blood pressure and fainting, so those are included in its label.
RLS may be associated with some other illnesses so I was very interested to see two reports of the use of pramipexole in bipolar depression as well as a report of its possible use in REM Behavior Sleep Disorder.
One of the most exciting potential uses for pramipexole may be in some people with fibromyalgia. I’ve mentioned that fibromyalgia, bipolar disorder and some other psychiatric illnesses may be connected. The idea that we might be able to use just one medicine to support our Integrated Medicine approach is very attractive, and also helps point us toward a deeper understanding of what exactly goes wrong at the physical level in RLS, depression and fibromyalgia.
I’ll keep you posted.
Dr. Richard G. Petty, MD is a world-renowned authority on the brain, and his revolutionary work on human energy systems has been acclaimed around the globe.
He is also an accredited specialist in internal and metabolic medicine, endocrinology, psychiatry, acupuncture and homeopathy. He has been an innovator and leader of the human potential movement for over thirty years and is also an active researcher, teacher, writer, professional speaker and broadcaster. He is the author of five books, including the groundbreaking and best selling CD series Healing, Meaning and Purpose. He has taught in over 45 countries and 48 states in the last ten years, but spends as much time as possible on his horse farm in Georgia.
