The quality of life issues, including those related to health, will most probably become one of the central problems of sustainable development in the 21st century. These issues are of paramount importance for both healthy populations and, especially, people affected by chronic disorders," commented Dr Yasuhiro Suzuki, an executive director at WHO in Geneva.
Parkinson's disease is one of the most common diseases affecting movement in people over age 55. It is chronic, meaning you will have it the rest of your life. It also is progressive, which means the symptoms grow worse over time. The disease may become disabling after many years. However, proper treatment should make it possible for you to lead a fulfilling, productive life.
The brain, there are two types of cells: neurons and neuroglia. Neurons are responsible for sending and receiving nerve impulses or signals. Neuroglia provide neurons with nourishment, protection and structural support. Collectively, there are more than one hundred billion neurons in the brain, comprising thousands of distinct types. Each of these neurons communicates with other neurons via specialized structures called synapses. More than one hundred distinct brain chemicals, called neurotransmitters, communicate across these synapses. In aggregate, there are probably more than 100 trillion synapses in the brain. Circuits, formed by hundreds or thousands of neurons, give rise to complex mental and behavioural processes.
In parkinson's disease , brain cells deteriorate (or degenerate) in an area of the brain called the substantia nigra. From the substantia nigra, specific nerve cell tracts connect to another part of the brain called the corpus striatum, where the neurotransmitter (a chemical messenger in the brain) called dopamine is released. Dopamine is an important neurotransmitter and alterations in its concentration can lead to different medical problems.
People who have Parkinson's disease experience tremors or shaking as a result of the damage to their nerve cells. Tremors caused by Parkinson's get worse when the person is at rest and better when the person moves. The tremor may affect one side of the body more than the other, and can affect the lower jaw, arms and legs.
Two studies have already provided clues that health-related quality of life may be affected by factors other than disease severity and drug therapy: A US-based study suggested that health-related quality of life might be seriously misjudged if inferred from clinical observations only. Another, more recent study in the UK has demonstrated that quality of life may not be strongly correlated with severity of Parkinson's disease but is affected by additional factors, such as the patients' access to a support group, the ability to gain the information and quality of contact they require, their use of non-drug therapies, etc.
The loss of these specific brain cells and decline in dopamine concentration are the cornerstone of signs and symptoms of PD as well as the target for treatment.Although doctors can prescribe drugs that control symptoms of the disease, there is nothing that can stop this neurological disease from getting worse.Since Parkinson's disease is a very gradual, progressive condition, it takes many patients and a significant period of time to demonstrate that drugs are having an impact on the course of the disease.
There is no cure for Parkinson's disease. But medicines can help control the symptoms of the disease. Some of the medicines used to treat Parkinson's disease include carbidopa-levodopa (one brand name: Sinemet), bromocriptine (brand name: Parlodel), selegiline (one brand name: Eldepryl), pramipexole (brand name: Mirapex), ropinirole (brand name: Requip), tolcapone (brand name: Tasmar) and pergolide (brand name: Permax).
Two drugs commonly used to treat Parkinson's disease can cause harm to heart valves, according to two studies in the New England Journal of Medicine.
The drugs, pergolide and cabergoline, are both from a class of medications called "ergot-derived dopamine receptor agonists." Ergot is a fungus, and ergot-derived drugs are used not only in the treatment of Parkinson's but also for restless leg syndrome and migraine headaches.
Ergot-derived dopamine receptor agonists were also in the now banned diet drug Fen-phen -- also associated with heart valve disease.
"We uncovered the biomedical reason why Fen-phen had particular side effects on the heart," said Dr. Bryan L. Roth, of the Department of Pharmacology at the University of North Carolina and author of an accompanying journal editorial.
"We evaluated other medications and predicted that they would have the same side effect on the heart," he said. "Our predictions were verified in these two studies."
Based on the new findings, Roth wants the U.S. Food and Drug Administration to look at all drugs that have this side effect with an eye to banning pergolide (brand named Permax) and cabergoline (Dostinex). "This side effect is very dangerous," he said. "It could result in an individual's death or undergoing valve replacement surgery," he added.
These types of drugs interact with a receptor in the heart valve, causing the valve to overgrow and become floppy and leaky, Roth explained.
In the first report, Dr. Edeltraut Garbe, from the Institute of Clinical Pharmacology, Charité, University Medicine, Berlin, and colleagues collected data on more than 11,000 people 40 to 80 years of age who were taking anti-Parkinson's drugs between 1988 and 2005.
The researchers found that, among 31 patients with newly diagnosed cardiac valve problems, six were taking pergolide, six were taking cabergoline, and 19 had not taken any dopamine agonist in the past year.
Almost 30 percent of the patients taking pergolide or cabergoline were at increased risk for heart valve problems.
"In this study, use of the dopamine agonists pergolide and cabergoline was associated with an increased risk of newly diagnosed cardiac-valve regurgitation," the authors concluded.
In the second study, a team of Italian researchers led by Dr. Renzo Zanettini, from the Istituti Clinici di Perfezionamento, Milan, studied 155 patients taking dopamine agonists for Parkinson's disease. Among these patients, 64 were taking pergolide, 49 were taking cabergoline, and 42 were taking non-ergot-derived dopamine agonists. In addition, there were 90 controls.
Zanettini's group found that about 23 percent of the patients taking pergolide had heart valve problems, as did about 29 percent of the patients taking cabergoline.
In contrast, none of the patients taking non-ergot-derived dopamine agonists had a heart problem, while 5.6 percent of the control patients did.
In addition, patients who took higher doses of pergolide or cabergoline had more advanced heart valve disease, the researchers reported.
"The frequency of clinically important valve regurgitation was significantly increased in patients taking pergolide or cabergoline, but not in patients taking non-ergot-derived dopamine agonists, as compared with control subjects," the researchers wrote. "These findings should be considered in evaluating the risk-benefit ratio of treatment with ergot derivatives," they concluded.
"If you have Parkinson's, you need to find out from your doctor if you're taking a medication that could cause this risk of serious heart damage," Roth said. "I would recommend not prescribing these medications at all. Our hope is that these two studies will encourage the FDA to remove these drugs from use."
Roth also noted that the drug Ecstasy also has the potential to damage the heart in the same way. "People who take Ecstasy on a regular basis may be at risk for this particular side effect," he said.
In a related story, a new drug to treat early Parkinson's, called transdermal rotigotine, has shown in a phase 3 clinical trial that it is safe and effective, according to a report in Neurology.
Rotigotine is a non-ergot-derived dopamine receptor agonist delivered via a patch designed for once-a-day application. The drug is currently being reviewed by the FDA. It is currently marketed in Europe as therapy for early-stage Parkinson's and has received a favorable review for advanced-stage Parkinson's, according to the German drug company Schwarz Pharma, the maker of rotigotine.
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