Aricept is normally taken once daily, at the physician recommended dose. Exelon is available in the form of a patch, or as a capsule. Reminyl ER is taken once daily and it has an extended release into the body. All of these medications aim to slow down the cognitive decline and general functioning. Another type of medication is Ebixa memantine.
Ebixa is available in a pill form and is usually taken twice daily. All of these medications aim to slow down the cognitive decline and general functioning associated with it.
Over time it robs people of their ability to remember, learn, and reason, cutting them off from friends and family and eventually even their own sense of self.
But a hard look through the research paints a far more disappointing picture. But the overall results are far less encouraging than the ads portray. More than half experience side effects. To clearly spell out the risks and benefits of these medications, Consumer Reports Best Buy Drugs commissioned Informulary, a company founded by Woloshin and another Dartmouth professor, Lisa Schwartz, M.
Their analysis is summarized in Drug Facts Boxes see separate links above , which are similar to the Nutrition Facts found on packaged foods. Among the few who do benefit, the improvement is typically slight. But they are not. They can cause side effects such as insomnia, nausea, muscle cramps, diarrhea, and reduced appetite, all of which can be troublesome for people with dementia.
Rarely, the drugs may cause more serious side effects such as internal bleeding and a slowed heart rate that could be potentially dangerous. Read the free report here. However, Caffarra et al. Others have reported improvements on measures of cognitive functioning over time with rivastigmine but only stability with donepezil [32]. Scharre and colleagues [33] found that patients with AD treated with rivastigmine had a lower rate of prescription of antipsychotic medication that those treated with donepezil.
Although a number of studies have compared donepezil and rivastigmine on measures of general cognitive functioning, there have been no investigations reported that have directly compared the effect of these medications on measures of working memory and attention. Hence, the purpose of the present investigation was to determine whether differential effects on measures of working memory and attention exist for AD patients taking donepezil versus rivastigmine.
Given that AChE and BChE are both known to hydrolyze ACh [34] and the aforementioned important role of the cholinergic system in attention, this might suggest an advantage for rivastigmine in the treatment of the attentional problems associated with AD. Some investigators have reported that whereas BChE inhibition in cerebral spinal fluid is related to performance on a measure of attention, AChE inhibition was not [35].
Hence, we predicted that rivastigmine would be associated with greater benefits on indices of attention and working memory, as compared to donepezil. The tests were administered in a pseudorandom fashion, although the MMSE was always administered first. However, a significant difference was noted for age between the groups, F 2, 33 4.
Please consult the table 1 for means and standard deviations for all demographic variables. Given the significant difference in age, all subsequent analyses were conducted using this variable as a covariate in a series of ANCOVAs to control for this potentially confounding variable.
The data from the Digit Span test were then analyzed. Please consult table 2 for the means and standard deviations for all dependent variables of interest and the figure 1 for a graphical representation. Note: Means and standard deviations are reported in parentheses. However, our data consistently indicated the opposite. The donepezil treated group evidenced significantly better performance on measures of working memory and attention when compared to the no treatment control group and also performed significantly better than the rivastigmine group on three of our four measures.
There was a significant difference in age between our groups, which could have affected the findings. However, we controlled for these age differences by including age as a covariate in all analyses. Hence, the analyses and subsequent obtained results had the influence of age removed.
The reason for the discrepancy between our hypothesis and the findings may be related to the regional cerebral effects of donepezil and the type of tests we used in our study. As mentioned, there is a tight coupling between working memory and selective attention. The ability to focus our cognitive resources on information relevant to our goals influences working memory performance. Furthermore, attention and working memory are increasingly viewed as overlapping constructs [36].
The working memory types of tasks used in this study require attentional processing and an inability to sustain attention vigilance as well as distractibility may cause impairments in these working memory tests. Gazzaley and Nobre [36] reviewed recent evidence from human neurophysiological studies which demonstrate that top-down modulation serves as a common neural mechanism underlying working memory and that these two cognitive operations engage prefrontal and parietal cortex.
Working memory, as well as attentional vigilance, appears to depend on frontal-parietal network. In addition, donepezil and rivastigmine are also known to possess regional differences in cerebral blood flow. Whereas patients who respond to donepezil exhibit increased cerebral blood flow to the anterior frontal lobe and the parietal lobe [37], patients who respond to rivastigmine exhibit increased blood flow to hippocampal structures and the prefrontal cortex [38].
These findings suggest that donepezil increases regional cerebral blood in those regions of the brain associated with vigilant attentional processing and working memory. These collective findings could potentially explain why donepezil was associated with better performance on the tests of working memory-attention used in our study.
Future research might want to focus on measuring the differential effects of donepezil and rivastigmine on more specific factors of attentional processing. There have been a few published reports comparing the effectiveness of donepezil versus rivastigmine in treating patients with LBD. Some have reported significant improvement in both cognitive and behavioral measures following treatment with either donepezil or rivastigmine [39], although donepezil was associated with a greater reduction in the total score from the Neuropsychiatric Inventory.
A thorough review of the literature by Simard and van Reekum [40] indicated that both donepezil and rivastigmine are efficacious in treating patients with LBD. However, other researchers have reported greater improvement in a range of cognitive and behavioral measures following treatment with rivastigmine as compared to donepezil, in patients with AD who also had symptoms suggestive of LBD [41]. A central feature of Lewy body dementia is the presence of disturbances in attention functioning.
Hence, given our current findings, the possibility exists that donepezil would be more efficacious in treating the attention-related deficits associated with LBD. Unfortunately, to date there have been no published reports that have compared donepezil and rivastigmine in specifically treating attention deficits in patients with LBD. Future research should be conducted to investigate this possibility.
Although our findings indicate differential effects on attention functioning between donepezil and rivastigmine, there are important limitations that should be considered. Our groups were heterogeneous in regard to diagnosis, with some patients being diagnosed only with AD but other patients having a mixed diagnosis of AD and VD.
The effect of including patients with dual diagnoses is not known, but this may have affected the findings. However, we attempted to control for this variable by including equal numbers of patient with AD and with both AD and VD within our groups. Hence, no one group contained more patients with VD than any other group. Perhaps the most serious limitation is the range of dosages of donepezil and rivastigmine that were included.
Higher dosages of either medication may have a more profound effect on attention and working memory. Review of the data indicates that half of the donepezil group were taking a large 10mg dosage but only three of the rivastigmine group were taking a larger 9.
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