April 24, 2000 -- A preliminary study of a new drug for Parkinson's disease suggests it is safe to use, but whether or not it actually works is another story.
When tested in animals together with other medications, remacemide hydrochloride appears to reduce Parkinson's disease symptoms. However, it does not decrease symptoms when used on its own in humans, according to an article in the April 25 issue of Neurology.
Parkinson's disease is a progressive disease that causes difficulty in walking and moving, stiff muscles, and tremors. It typically affects the elderly, but can affect adults in their 30s and 40s and occasionally affects children. It is caused by a decrease of cells in the brain that produce a chemical called dopamine, which is important for regulating the body's movement.
Parkinson's disease is often treated with levodopa, a drug that helps replace dopamine. Because of the side effects of levodopa, which is sold under the brand names Dopar and Larodopa, other drugs have also been developed. Certain brain surgeries have also relieved symptoms in some patients. Currently, there is no cure for Parkinson's disease.
Research has suggested that some of the symptoms of Parkinson's disease may be caused by overactivity of a chemical in the brain called glutamate. Stanley Fahn, MD, who served on the steering committee of the Parkinson Study Group, and the author of the paper, tells WebMD that remacemide may work to block one of the glutamate receptors in the brain. Fahn is also a professor of neurology at Columbia University School of Medicine in New York City.
In this study, 200 patients with early Parkinson's disease who were not taking levodopa or other dopamine drugs received varying levels of remacemide hydrochloride or a sugar pill twice a day for five weeks.
While some patients reported nausea and dizziness, there were no serious side effects. Those who experienced strong side effects at higher dosage levels were allowed to divide the medication into four doses. However, 85% of the patients were able to tolerate the drug.
Although previous studies in animals had shown improvement of symptoms, there was no evidence of that in the patients taking remacemide for this study.
"The people who did this research are the best people in the country to do a study like this," says Abraham Lieberman, MD. "However, this time they didn't come up with very striking results." Lieberman, who is a consultant to WebMD, is the national medical director of the National Parkinson Foundation Inc. in Miami.
Even though remacemide did not reduce Parkinson's symptoms when used on its own, it may still be useful when combined with other medications. "Work in monkeys suggests when remacemide is combined with a low dose of levodopa, the combination is effective," Fahn says. This possibility is being tested in a human study currently under way.
In addition, the authors speculate that even though remacemide blocks one of the glutamate receptors in the brain without having a measurable effect on Parkinson's symptoms, it should be tested for its effect on the progression of Parkinson's disease.
Parkinson's often starts out with a few low-level symptoms. "When patients first come in, they say, 'If we could just stop it in its tracks, I could live with these little symptoms,'" Fahn says. "At present, we don't have any medications that can stop the progression of Parkinson's disease, so finding one would be very important."
It's conceivable that remacemide may slow progression of the disease, Lieberman says. "However, these studies cost a great deal of money, and our ability to follow the progression of the disease is not very good. If the pharmaceutical companies decide not to fund further studies of [the] ... protective effects of remacemide, I couldn't fault that decision."
- A new drug known as remacemide does not seem to be effective in reducing symptoms of Parkinson's disease when used by itself.
- Based on studies in monkeys, researchers are now testing whether the drug could be beneficial when used in combination with other drugs, such as levodopa.
- Remacemide is believed to help motor complications because it blocks glutamate receptors in the brain, preventing cells from becoming overexcited.