The Seizure Drug Zonisamide May Help Ease Symptoms of Lewy Body Dementia
The drug is called zonisamide (Zonegran). When added to treatment with the drug levodopa, zonisamide helped to control Parkinson's disease-like movement symptoms that are associated with Lewy body dementia. These symptoms may include tremors, stiffness, slowness and trouble walking.
This finding could be significant, dementia researchers said.
While higher doses of levodopa can also help control movement symptoms, they can cause serious psychiatric side effects, including hallucinations, in people with Lewy body dementia. Zonisamide didn't appear to increase psychiatric problems or worsen memory troubles in this 12-week study from Japan.
"Movement symptoms in Lewy body dementia are problematic to treat with standard Parkinson's disease medications, because they can provoke hallucinations," said Dr. Daniel Kaufer, director of the University of North Carolina Chapel Hill Memory Disorders Program. Kaufer wasn't involved in the new research.
"Zonisamide improved motor function in a dose-dependent manner, without inducing serious side effects," Kaufer said.
However, the drug would not have any effect on the memory problems associated with this type of dementia, he said.
Lewy body dementia affects about 1.4 million people in the United States, and is the second most common type of dementia after Alzheimer's disease, according to the Lewy Body Dementia Association.
Symptoms vary, but may include memory and thinking problems, difficulty understanding visual information, trouble with attention, Parkinson's-like movement symptoms, hallucinations and changes in sleep or behavior.
Kaufer said treatment options for this and other neurodegenerative diseases are limited, so any advance is welcome. Zonisamide is already approved by the U.S. Food and Drug Administration for treatment of seizures.
The study was led by Dr. Miho Murata from the National Center of Neurology and Psychiatry in Tokyo and sponsored by zonisamide's Asian manufacturer, Sumitomo Dainippon Pharma, in Japan.
It included 158 people diagnosed with probable Lewy body dementia. (As with other forms of dementia, the only way to definitively diagnose Lewy body dementia is after death with an autopsy.)
The study volunteers were already receiving treatment with the Parkinson's drug levodopa.
They were given a placebo for four weeks at the start of the study. Then they were randomly placed into one of three groups that received a placebo, 25 milligrams or 50 milligrams of zonisamide once daily.
The participants who received the highest dose of zonisamide had the most improvement in their movement symptoms compared to a placebo. Those who received the smaller dose had slight improvements over a placebo, according to the study.
Kaufer said the drug showed a clear-cut dose response, which indicates the medication is working.
"This study identifies another potential therapeutic option for a circumstance that is not uncommon. The results weren't earth-shattering, but zonisamide could be a viable treatment option to improve quality of life," he said.
Dr. Sami Saba, a neurologist at Lenox Hill Hospital in New York City, agreed that zonisamide could be beneficial.
"Zonisamide looks pretty effective at improving movement symptoms and not causing psychiatric symptoms," said Saba, who wasn't involved in the research.
"This is known to be a difficult disease to treat, and this adds to the cadre of things we can use that may help this subset of patients," he added.
The study authors noted that the current study size was small, and said a larger study is needed.
The findings were published online Jan. 24 in the journal Neurology.
Learn more about Lewy body dementia from the Lewy Body Dementia Association.
Posted: January 2018