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SYDNEY -- Parkinson's disease patients who have impaired cognition appeared to benefit from the Alzheimer's disease medicine donepezil (Aricept) -- with no detriment to their motor skills, researchers reported here.
A meta-analysis of four studies showed a mean change in the Mini-Mental State Examination (MMSE) of 1.53 (1.17-2.15) in favor of donepezil compared with placebo (Z=6.32; P>0.00001, for overall effect), said Leah Shiong Shu, MD, chief resident in adult neurology at Philippine General Hospital in Manila.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- Note that this meta-analysis of four randomized, controlled trials demonstrated that donepezil is efficacious in terms of improving scores on the Mini-Mental State Exam (MMSE) in patients with Parkinson's disease and cognitive impairment.
- Be aware that more than 90% of the patients in this analysis came from a single large trial, which largely drives these results.
None of the studies scrutinized for the meta-analysis showed any impact of donepezil therapy on the Unified Parkinson's Disease Rating Scale (UPDRS), Shiong Shu reported at her poster presentation at the International Congress on Parkinson's Disease and Movement Disorders.
"Consequently, the demonstration of the drug having no significant impact on the motor symptoms of Parkinson's disease (P=0.18) as measured by the UPDRS makes it plausible to administer donepezil to such patients," she said.
"However, the common side effects with donepezil -- nausea, headache, insomnia and dizziness -- should caution doctors to judge if these patients should be prescribed donepezil," Shiong Shu told ľֱ. "Hence, treatment with donepezil of Parkinson's disease patients with cognitive impairment should still be individualized."
In performing the meta-analysis, Shiong Shu and colleagues sought randomized controlled studies in the literature that described the use of cholinesterase inhibitors in the treatment of cognitive dysfunction among patients with Parkinson's disease. They initially identified 55 papers, but 44 were not randomized trials. Five trials are ongoing, and two of the remaining six trials involve treatment with rivastigmine (Exelon).
The remaining four trials included 201 patients who were assigned to placebo and 194 to donepezil. However, about 95% of the patients were from one large randomized trial. The other three trials included in the analysis had fewer than 20 patients in each.
Shiong Shu and her research team suggested that prospective studies are needed to provide a more definitive answer to the role of donepezil in this patient population.
"There is an ongoing study in the U.K. looking at the use of donepezil in early Parkinson's disease dementia and looking prospectively at treatment over a 2-year period," Alison Yarnall, MD, a research registrar at the University of Newcastle in England, told ľֱ.
"In this meta-analysis, the numbers of patients are small and the time period that donepezil is used is short," she noted. "What we need before we can endorse donepezil for treatment in these patients are larger randomized, multicenter trials to show that it is effective" especially in light of resource constraints on healthcare, both in the U.K. and the U.S.
Shiong Shu said her Philippine research team understood that "donepezil has been proven effective in patients with Alzheimer's disease. However, its role in the management of cognitive impairment in other neurodegenerative diseases such as Parkinson's disease and diffuse Lewy body dementia is not known."
Hence, the researchers undertook the meta-analysis to see if they could determine donepezil's effectiveness.
Disclosures
Shiong Shu and Yarnell had no disclosures.
Primary Source
Movement Disorder Society
Source Reference: Barcelon E, et al "Meta analysis: Donepezil in the treatment of cognitive impairment & dementia in patients with Parkinson's disease" MDS 2013.