An experimental drug that may improve Parkinson's disease symptoms when used in conjunction with current therapies is safe for use by Parkinson's patients, according to a study published by the Parkinson Study Group in the April 25 issue of Neurology, the American Academy of Neurology's scientific journal.
Researchers found that Parkinson's disease patients did not improve when using the drug -- remacemide hydrochloride -- alone. However, recent preliminary studies have shown that remacemide hydrochloride, used in addition to currently prescribed dopaminergic drugs, such as levodopa, reduces Parkinson's disease symptoms and may slow disease progression.
"Our primary goal was to learn how to use the drug safely," said neurologist and study corresponding-author Steven Schwid, MD, at the University of Rochester in New York. "If ongoing studies confirm that remacemide used in conjunction with dopaminergic therapy improves patients' symptoms, it may be the first of a new class of Parkinson's therapies. If it is also proved to have neuroprotective qualities by preventing the progression of the disease, it could be an even more significant advance in the treatment of Parkinson's disease."
The study included 200 patients with early Parkinson's who were not taking levodopa or other dopamine drugs. Patients received 150, 300 or 600 mg of remacemide hydrochloride or placebo (inactive pill) daily for five weeks. Patients who could not tolerate the daily amount in the prescribed two dosages were allowed to divide the daily amount into four doses.
Of the patients receiving the 300 and 600 mg dosages, 85 percent were able to complete the study on their assigned dosage. Ninety-six percent of those taking 150 mg and 98 percent of those receiving placebo completed the study. Some patients reported nausea and dizziness, but no serious side effects were noted.
Rating scales used to evaluate patients' mental function, mobility and ability to complete common daily activities remained stable among patients receiving remacemide.
"Research has suggested that over-activity of a neurotransmitter in the brain called glutamate, contributes to some signs and symptoms of Parkinson's," Schwid explained. "Glutamate causes excitation of certain brain cells or neurons, which may lead to brain cell death and Parkinson's progression. Reducing glutamate activity in the brain might improve Parkinson's symptoms and slow worsening of the disease."
Remacemide hydrochloride interferes with glutamate activity and has improved symptoms in animal models of Parkinson's disease. The drug also has been used in clinical trials for epilepsy, acute stroke and Huntington's disease. Parkinson's disease, a chronic neurologic disease that impairs mobility, is caused, in part, by a progressive loss of dopamine producing brain cells. While treatment with dopaminergeric drugs, such as levodopa, have provided substantial relief for most patients with Parkinson's disease, the drugs tend to be less effective in treating fluctuating symptoms after five years. The study was performed by the Parkinson Study Group at 21 medical centers nationwide, in a collaborative effort to gather and analyze Parkinson's data, and was supported by Astra Pharmaceuticals.
The American Academy of Neurology, an association of more than 16,500 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research.
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