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Donepezil for mild and moderate Alzheimer's disease.

BACKGROUND: Alzheimer's disease is the most common cause of dementia and is a primary degenerative disease of the brain of unknown cause. Onset is usually late in life with increasing impairment of memory, developing gradually into a global impairment of cognition, orientation, linguistic ability and judgement. The clinical course is accompanied by growing disability and dependency on care. One of the characteristic features of the disease is the widely variable rate of progression seen in different patients. Acetylcholine is an important neurotransmitter associated with memory, and abnormalities in cholinergic neurones (including cell loss) are among the many neurological and neurochemical abnormalities that develop in AD. One approach to lessening the impact of these abnormalities is to inhibit the breakdown of acetylcholine by blocking the relevant enzyme. Tacrine was the first compound approved as a treatment for AD in the US and worked in this way, but caused severe side effects. E2020 (donepezil, Aricept) is a second generation cholinesterase inhibitor and appears to be highly specific, with relatively few side effects. OBJECTIVES: The objective of this review is to assess whether or not donepezil improves the well-being of patients with mild or moderate Alzheimer's disease. SEARCH STRATEGY: The Cochrane Dementia and Cognitive Impairment Group Register of Clinical Trials, was searched using the terms 'donepezil', 'E2020' and 'ARICEPT'. Medline, PsychLIT and EMBASE electronic databases were searched with the above terms. Members of the Donepezil Study Group and Eisai Inc were contacted. SELECTION CRITERIA: All unconfounded, double-blind, randomised controlled trials in which treatment with donepezil was administered for more than a day and compared with placebo in patients with Alzheimer's disease. DATA COLLECTION AND ANALYSIS: Data were extracted independently by the reviewers (JSB & DB), pooled where appropriate and possible, and the weighted or standardised mean differences or Peto odds ratios (95%CI) estimated. Where possible, intention-to-treat data were used. MAIN RESULTS: There are 4 included trials, covering treatment of 12 or 24 weeks duration in highly selected patients. The only information available on one trial (Gauthier 1998) is a conference abstract which reports no usable results. Available outcome data cover domains including cognitive function and global clinical state, but data on several important dimensions of outcome are not available. The results of three trials suggest a small beneficial effect of donepezil in improving cognitive function: at a 5mg/day dose, improvements measured -2.6 points (95%CI -3.5 -- -1.8) on weighted mean difference, in the midrange of the 70 point ADAS-Cog scale. The results of two trials show some improvement in global clinical state (assessed by an independent clinician) in those treated with donepezil compared to placebo. The patient's own rating of their Quality of Life showed no benefit of donepezil compared with placebo. There were significantly more withdrawals before the end of treatment from the 10mg/d (but not the 5mg/d) donepezil group compared with placebo, which may have resulted in some overestimation of beneficial changes at 10mg/d in progressively declining characteristics, as last available measures were used in analyses. A variety of adverse effects were recorded, but very few patients left a trial as a direct result of the intervention. REVIEWER'S CONCLUSIONS: In selected patients with mild or moderate Alzheimer's disease treated for periods of 12 or 24 weeks, donepezil produced modest improvements in cognitive function and study clinicians rated global clinical state more positively in treated patients. No improvements were present on patient self-assessed quality of life and data on many important outcomes are not available. The practical importance of these changes to patients and carers is unclear.

Alzheimer Disease↗

Donepezil improves cognition and global function in Alzheimer disease: a 15-week, double-blind, placebo-controlled study. Donepezil Study Group.

BACKGROUND: Donepezil hydrochloride (Aricept) is a selective acetylcholinesterase inhibitor developed for the treatment of Alzheimer disease. This phase 3 study was 1 of 2 pivotal trials undertaken to establish the efficacy and safety of using donepezil in patients with mild to moderately severe Alzheimer disease. OBJECTIVES: To further examine the efficacy and safety of using donepezil in the treatment of patients with mild to moderately severe Alzheimer disease. To examine the relationships between plasma donepezil concentrations, inhibition of red blood cell acetylcholinesterase activity, and clinical response. METHODS: This was a 12-week, double-blind, placebo-controlled, parallel-group trial with a 3-week single-blind washout. Outpatients at 23 centers in the United States were randomized to receive placebo, 5 mg of donepezil hydrochloride, or 10 mg of donepezil hydrochloride (5 mg/d during week 1 then 10 mg/d thereafter) administered once daily at bedtime. Primary efficacy was measured using the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) and Clinician's Interview-Based Impression of Change including caregiver information (CIBIC plus). RESULTS: A total of 468 patients entered the study, more than 97% of whom were included in the intention-to-treat (end point) analyses. The use of donepezil produced statistically significant improvements in ADAS-cog, CIBIC plus, and Mini-Mental State Examination scores, relative to placebo. The mean drug-placebo differences, at end point, for the groups receiving 5 mg/d and 10 mg/d of donepezil hydrochloride were, respectively, 2.5 and 3.1 units for ADAS-cog (P<.001); 0.3 and 0.4 units for CIBIC plus (P< or =.008); and 1.0 and 1.3 units for Mini-Mental State Examination (P< or =.004). On the CIBIC plus scale, 32% and 38% of patients, respectively, treated with 5 mg/d and 10 mg/d of donepezil hydrochloride demonstrated clinical improvement (a score of 1, 2, or 3) compared with placebo (18%). The mean (+/-SEM) donepezil plasma concentrations at study end point were 25.9 +/- 0.7 ng/mL and 50.6 +/- 1.9 ng/mL in the groups receiving dosages of 5 mg/d and 10 mg/d, respectively. Corresponding mean (+/-SEM) percentages of inhibition of red blood cell acetylcholinesterase activity were 63.9% +/- 0.9% and 74.7% +/- 1.2% for these 2 dosages, respectively. There was a statistically significant positive correlation between plasma concentrations of donepezil and acetylcholinesterase inhibition; the EC50 (50% effect) was obtained at a concentration of 15.6 ng/mL. A plateau of inhibition (80%-90%) was reached at plasma donepezil concentrations higher than 50 ng/mL. The correlations between plasma drug concentrations and both ADAS-cog (P<.001) and CIBIC plus (P = .006) were also statistically significant, as were the correlations between red blood cell acetylcholinesterase inhibition and change in ADAS-cog (P<.001) and CIBIC plus (P = .005). The incidence of treatment-emergent adverse events with both dosages of donepezil (68%-78%) was comparable with that observed with placebo (69%). The use of 10 mg/d of donepezil hydrochloride was associated with transient mild nausea, insomnia, and diarrhea. There were no treatment-emergent clinically significant changes in vital signs or clinical laboratory test results. More important, the use of donepezil was not associated with the hepatotoxic effects observed with acridine-based cholinesterase inhibitors. CONCLUSION: Donepezil hydrochloride (5 and 10 mg) administered once daily is a well-tolerated and efficacious agent for treating the symptoms of mild to moderately severe Alzheimer disease.

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The efficacy and safety of donepezil in patients with Alzheimer's disease: results of a US Multicentre, Randomized, Double-Blind, Placebo-Controlled Trial. The Donepezil Study Group.

This study evaluated the efficacy and safety of donepezil in patients with mild to moderately severe Alzheimer's disease, and examined the relationships between plasma donepezil concentration, red blood cell acetylcholinesterase (AChE) activity and clinical response. The trial was of a multicenter, double-blind, parallel-group design and patients were randomised to once-daily treatment with either donepezil (1, 3 or 5 mg) or placebo. The 12-week double-blind phase was followed by a 2-week single-blind placebo washout. 161 patients (55-85 years of age) entered the study and 141 completed treatment. Patients treated with donepezil showed dose-related improvements in the Alzheimer's Disease Assessment Scale-cognitive subscale score (ADAS-cog) and in MMSF scores. The improvements in ADAS-cog were statistically significantly greater with donepezil 5 mg/day than with placebo. There was a 50% reduction in the percentage of patients showing clinical decline with donepezil at 5 mg/day (11%) relative to placebo (20%). In addition, a statistically significant correlation between plasma concentrations of donepezil and AChE inhibition was demonstrated. A plateau of inhibition (76-84%) was reached at plasma donepezil concentrations > 50 ng/ml. The correlation between plasma drug concentrations and ADAS-cog (p = 0.014), MMSE (p = 0.023) and patient quality of life scores, assessed by the patient (p = 0.037) were also statistically significant, as was the correlation between AChE inhibition and change in ADAS-cog (p = 0.008). The incidence of treatment-emergent adverse events with all three dosages of donepezil (64-68%) was comparable to that observed with placebo (65%). Donepezil had no clinically significant effect on vital signs, haematology or clinical biochemistry tests. Importantly, donepezil was not associated with any hepatotoxicity, as observed with acridine-based cholinesterase inhibitors.

Acetylcholinesterase↗

A 24-week, double-blind, placebo-controlled trial of donepezil in patients with Alzheimer's disease. Donepezil Study Group.

The efficacy and safety of donepezil as a treatment for patients with mild to moderate Alzheimer's disease (AD) was investigated in a multicenter, double-blind study. Patients were randomly assigned to treatment with placebo (n = 162), 5 mg/d donepezil (n = 154), or 10 mg/d donepezil (n = 157) for 24 weeks followed by a 6-week, single-blind placebo washout. The primary efficacy measures were the cognitive portion of the Alzheimer's Disease Assessment Scale (ADAS-cog) and the Clinician's Interview Based Assessment of Change-Plus (CIBIC plus), with the Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of the Boxes (CDR-SB), and patient rated Quality of Life (QoL) used as secondary measures. Cognitive function, as measured by the ADAS-cog, was significantly improved in the 5- and 10-mg/d donepezil groups as compared with the placebo group at weeks 12, 18, and 24. Clinician's global ratings on the CIBIC plus also improved in both the 5- and 10-mg/d donepezil groups relative to placebo. At the end of the 6-week placebo washout phase, ADAS-cog scores and CIBIC plus ratings were not significantly different for the three groups. Significant treatment benefits were also observed consistently in both the 5- and 10-mg/d groups on the MMSE and the CDR-SB, but there was no consistent effect on the patient-rated QoL. Cholinergic side effects (primarily diarrhea, nausea, and vomiting) were reported more often in the 10-mg/d group than either the 5-mg/d or placebo groups. Side effects were transient and generally mild in severity. These data indicate that donepezil is a well-tolerated drug that improves cognition and global function in patients with mild to moderate AD.

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[A case of acute cholinergic adverse effects induced by donepezil overdose: a follow-up of clinical course and plasma concentration of donepezil].

A 79-year-old woman with Alzheimer's disease was admitted due to acute cholinergic symptoms induced by overdose (45 mg) of donepezil (DPZ). Physical examination showed bradycardia, sinus arrhythmia, vomiting and respiratory insufficiency. She was treated with atropine intravenously and her cholinergic symptoms subsided in the next evening. After 5 days she was discharged from the hospital and DPZ was withholded for about 4 weeks. The plasma concentration of DPZ was 54.6 ng/ml on admission and gradually decreased to the normal limits in about 90 hours. The calculative half-life of DPZ was about 55 hours. Since the half-life of DPZ is long and differs between individuals, hospitalization and treatment with atropine is recommended for cholinergic side effects induced by overdose of DPZ. It is important to prevent dosing errors in cooperation with medical providers, patients and families.

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Donepezil for vascular cognitive impairment.

BACKGROUND: Vascular disease is the second commonest cause of dementia after Alzheimer's disease. There are difficulties in classifying patients with this type of cognitive impairment owing to varied clinical presentation and different types of arterial disease. There is some degree of overlap in the neuropathology of Alzheimer's and vascular dementia. Deficient cholinergic neurotransmission, a characteristic of Alzheimer's disease, has been postulated to contribute to the cognitive impairment of vascular disease of the brain. Cholinesterase inhibitors, such as donepezil, may therefore be a rational treatment. OBJECTIVES: To assess the clinical efficacy and tolerability of donepezil on cognitive function, clinical global impression, activities of daily living and social functioning of people with vascular cognitive impairment. SEARCH STRATEGY: Relevant randomized controlled trials were identified from a search of the Cochrane Dementia and Cognitive Improvement Group Specialized Register on 21 July 2003 using the terms donepezil, E2020 and Aricept. This Register consists of records from all major healthcare databases and many ongoing trials databases. Unpublished trials were requested from the drug company Eisai Inc and they provided us with the required data. SELECTION CRITERIA: All unconfounded randomized double-blind trials comparing donepezil with placebo were eligible for inclusion. Trials using combinations of donepezil with other pharmacological interventions were excluded. DATA COLLECTION AND ANALYSIS: Both reviewers assessed studies against the criteria for inclusion and extracted data. Data were pooled where appropriate, and weighted mean differences or Peto odds ratios with 95% confidence intervals calculated. Intention-to-treat analysis was undertaken when possible. MAIN RESULTS: Two large-scale, randomized, double-blind, parallel-group controlled trials were identified for inclusion. A total of 1219 people with mild to moderate cognitive decline due to probable or possible vascular dementia (according to the NINCDS/AIREN criteria and the Hachinski Ischemia Scale) were recruited. Donepezil, at doses of 5 or 10 mg a day was compared with placebo for 24 weeks. For each outcome measure, mean change from baseline at weeks 12 and 24, using a last observation carried forward analysis, was calculated. Cognitive function: The donepezil groups showed statistically significantly better performance than the placebo groups on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog) at 12 and 24 weeks. The donepezil groups produced statistically significantly better scores than the placebo groups on the Mini-Mental State Examination (MMSE) at 12 and 24 weeks. Global function: The sum of the boxes of the Clinical Dementia Rating (CDR-SB) showed at 24 weeks a statistically significant benefit of 10 mg donepezil daily over both placebo and a 5 mg daily dosage. The Clinician's Interview-Based Impression of Change-plus version (CIBIC-plus) showed improved global function of participants taking 5 mg of donepezil daily compared with the placebo group but this was not seen in the higher dose group. Activities of daily living and social behaviour: On the Instrumental Activity of Daily Living (IADL) scale, there was no statistically significant difference between the groups taking donepezil 5mg per day donepezil and placebo, but the group taking 10 mg of donepezil a day showed benefit compared with placebo There were statistically significant benefit for donepezil at either dosage compared with placebo on the Alzheimer's Disease Functional Assessment and Change Scale (ADFACS). Tolerability and adverse effects: Broad range of adverse events were reported in the studies and data confirmed that donepezil was well tolerated, and most of the side effects were transient and were resolved by stopping the medication. Some of these events, especially nausea, diarrhoea, anorexia and cramp appeared more frequently on the 10 mg dose where there was a statistically significant difference compared with placebo. Drop-out: The drop-out rate was similar between the groups, 84.2% (330) patients completed the studies. The withdrawal rate was low and due mainly to side effects. REVIEWER'S CONCLUSIONS: Evidence from the available studies support the benefit of donepezil in improving cognition function, clinical global impression and activities of daily living in patients with probable or possible mild to moderate vascular cognitive impairment after 6 months treatment. Extending studies for longer periods would be desirable to establish the efficacy of donepezil in patients with advanced stages of cognitive impairment. Moreover, there is an urgent need for establishing specific clinical diagnostic criteria and rating scales for vascular cognitive impairment.

Activities of Daily Living↗

Donepezil for mild cognitive impairment.

BACKGROUND: Problems with memory which do not meet the diagnostic criteria for dementia, usually called mild cognitive impairment (MCI), can be the first sign of an impending dementia, particularly Alzheimer's disease (AD). There is no consensus on a definition or diagnostic criteria for MCI, and MCI remains a vague term and those so described are a heterogeneous population, consisting of people who may rapidly progress to dementia but also of people with stable cognitive deficits and some who may actually improve. Treatment in the very earliest stages of AD may delay progression to AD. Donepezil (Aricept, E2020), a cholinesterase inhibitor, has been shown to benefit all severities of AD including mild and it would be reasonable to investigate its efficacy for those with MCI. OBJECTIVES: To assess the effects of donepezil in people with mild cognitive impairment but no diagnosis of dementia. SEARCH STRATEGY: The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 6 January 2006. This register contains records from major health care databases like CENTRAL, MEDLINE, EMBASE, CINAHL and PsycINFO and many ongoing trial databases and is updated regularly. SELECTION CRITERIA: All double blind, randomized trials in which treatment with donepezil was compared with placebo for patients with mild cognitive impairment. DATA COLLECTION AND ANALYSIS: Data were extracted from the published reports of the included studies, pooled where appropriate and the treatment effects or the risks and benefits estimated. MAIN RESULTS: The two included studies, with a total of 782 patients, all with a MMSE greater than 23 points, identified similar patients for inclusion, but were quite different with respect to design and objective. Pooling results in a meta-analysis was not possible. In the first study the 13-item ADAS-Cog showed benefit associated with 10 mg/day donepezil compared with placebo at 24 weeks (MD 1.90, 95% CI 0.51 to 3.29, p=0.007), but four other measures of cognitive function did not. The analysis of withdrawals before the end of treatment at 24 weeks, withdrawals due to an adverse event, and numbers experiencing an adverse event, showed a significant difference between the donepezil group and the placebo group in favour of placebo, (43/133 donepezil 23/137 placebo, OR 2.37, 95% CI 1.33 to 4.22, p=0.003), (29/133 donepezil 10/137 placebo, OR 3.54, 95% CI 1.65 to 7.60, p=0.001), (116/133 donepezil, 100/137 placebo, OR 2.52 95% CI 1.34 to 4.76, p=0.004). Various adverse effects were recorded, and several types of event, diarrhoea, nausea, vomiting, leg cramps and abnormal dreams, were reported more frequently in the donepezil group compared with the placebo. In the second study there was a significant difference between the number of patients diagnosed with AD or another dementia between the donepezil group and the placebo group in favour of donepezil after one year of treatment (16/253 donepezil 38/259 placebo) (OR 0.39, 95% CI 0.21 to 0.72, p=0.003), but no difference after 3 years of treatment (63/253 donepezil 73/259 placebo) (OR 0.84, 95% CI 0.57 to 1.25, p=0.4). AUTHORS' CONCLUSIONS: There are two included studies. One study demonstrated a modest treatment effect in cognitive function as assessed by ADAS-Cog13 but not for other outcomes assessing different domains of cognitive function. Donepezil was associated with significantly more adverse effects compared with placebo, mostly gastrointestinal. From the second study, there is no evidence that donepezil delays the onset of AD. There is no evidence to support the use of donepezil for patients with MCI. The putative benefits are minor, short lived and associated with significant side effects.

Donepezil↗

Donepezil: a review of its use in Alzheimer's disease.

Donepezil (E-2020) is a reversible, noncompetitive, piperidine-type cholinesterase inhibitor. It is selective for acetylcholinesterase rather than butyrylcholinesterase. Donepezil 5 and 10 mg/day significantly improved cognition and global clinical function compared with placebo in well designed short term trials (14 to 30 weeks) in 161 to 818 patients with mild to moderate Alzheimer's disease. Beneficial effects on cognition were observed from week 3 of treatment. Donepezil 10 mg/day significantly delayed the deterioration in activities of daily living (ADL) [by 55 weeks] compared with placebo in a retrospective analysis of 1 trial, and in the largest trial significantly improved patients' abilities to perform complex tasks. However, no significant improvement in function was observed with donepezil 5 mg/day in another trial. In the 2 trials of longest duration donepezil (5 and 10 mg) significantly delayed symptomatic progression of the disease. While there was no evidence for a positive effect of donepezil on patients' quality of life, there are no validated measures of this parameter specific to patients with Alzheimer's disease. Donepezil (5 and 10 mg) significantly reduced caregiver burden. Long term efficacy data suggest that improvements in cognition, global function or ADL are maintained for about 21 to 81 weeks with donepezil (10 mg/day in most patients). Donepezil is generally well tolerated with the majority of adverse events being mild and transient. Predictably, most events were cholinergic in nature and generally related to the gastrointestinal and nervous systems. The incidence of these events was significantly higher with donepezil 10 mg than with placebo in short term clinical trials; however, this may have been due to the 7-day dose increase schedule used in these studies and can be minimised by increasing the dose after a longer (6-week) period. The incidence of serious adverse events was generally similar between donepezil 5 and 10 mg (4 to 10%) and placebo (5 to 9%) in short term trials. 26% of patients receiving donepezil (5 and 10 mg) reported serious events over a 98-week period in a long term trial. Importantly, there was no evidence of hepatotoxicity with this drug. Conclusions. Donepezil (5 and 10 mg) is an agent with a simple once-daily dosage schedule which improves cognition and global clinical function in the short (up to 24 weeks) and long term (up to about 1 year) in patients with mild to moderate Alzheimer's disease. Improvements in ADL were also observed with donepezil 10 mg/day. Adverse events associated with donepezil are mainly cholinergic. Donepezil has been extensively studied and should be considered as a first-line treatment in patients with mild to moderate Alzheimer's disease.

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Estimation of plasma IC50 of donepezil hydrochloride for brain acetylcholinesterase inhibition in monkey using N-[11C]methylpiperidin-4-yl acetate ([11C]MP4A) and PET.

Donepezil hydrochloride is a potent and selective inhibitor for brain acetylcholinesterase (AChE) and is currently used worldwide for the treatment of Alzheimer's disease. Until now, there is no in vivo study on the relation between the plasma concentration and the brain AChE inhibition. The purpose of this study was to estimate in vivo plasma IC(50) of donepezil in living monkeys by measuring plasma donepezil concentration (LC/MS/MS) and brain AChE activity with positron emission tomography (PET) and N-[(11)C]methylpiperidin-4-yl acetate, which is an acetylcholine analog recently developed by us for quantifying in vivo brain AChE activity. PET scans with donepezil at two doses, 100 microg/kg (donepezil-1; N=5) or 250 microg/kg (donepezil-2; N=5), were performed using the same monkeys at 4-week intervals. Before each PET scan, baseline PET scans (N=10 in total) were performed without donepezil. The plasma donepezil concentrations 14 min after intravenous injection were proportional to the doses, 17.2+/-2.9 ng/ml (donepezil-1) and 44.0+/-5.0 ng/ml (donepezil-2), and the mean AChE inhibitions in four neocortical regions as evaluated by PET were also dose-dependent, 27% (donepezil-1) and 53% (donepezil-2). In IC(50) estimation, measured plasma donepezil concentrations were corrected for the change during PET scan. The IC(50) values (estimate+/-SE) were 42+/-9.0 (ng/ml; donepezil-1), 34+/-3.2 (donepezil-2), and 37+/-4.1 (combined data). The present method may be useful for in vivo evaluation of other AChE inhibitors and novel drugs.

Acetylcholinesterase↗

Concurrent administration of donepezil HCl and levodopa/carbidopa in patients with Parkinson's disease: assessment of pharmacokinetic changes and safety following multiple oral doses.

AIM: The use of acetylcholinesterase inhibitors for the treatment of comorbid Alzheimer's disease in Parkinson's disease (PD) patients stabilized on a levodopa regimen may potentially disrupt cholinergic balance. This randomized, double-blind, crossover study investigated the safety of, and possible drug-drug interaction between, donepezil HCl and levodopa/carbidopa. METHODS: Twenty-five patients with PD who were taking physician-optimized doses of levodopa/carbidopa (with daytime dosing intervals of 4-8 h) were administered once-daily doses of either donepezil HCl (5 mg) or placebo for 15 days, in two treatment periods, separated by a washout of at least 2 weeks. Some patients took a second dose of levodopa/carbidopa after 4 h, therefore subanalysis of the levodopa/carbidopa data was conducted up to 4 h and 8 h after dosing. Twenty-six healthy matched controls received open-label donepezil HCl only, for a single 15-day period. Blood samples were collected before, during and after the 15 doses of donepezil HCl for pharmacokinetic (PK) assessments. Pharmacokinetic parameters included maximum attained plasma drug concentration (C(max)), time at which C(max) is attained (t(max)), plasma drug concentration at steady state (C(ss)), and area under the drug concentration-time curve over the dosing interval. Safety assessments included monitoring adverse events, and the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination. RESULTS: The mean age of all subjects was 72.6 +/- 1.3 years. Donepezil PK assessments of PD patients receiving levodopa/carbidopa were similar to the PK results from healthy controls who received donepezil HCl only (mean AUC(0-12 h)= 281.6 +/- 17.6 and 268.6 +/- 19.9 ng.h ml(-1), respectively). Carbidopa PK were not significantly altered by the concomitant administration of multiple doses of donepezil HCl, compared with when PD patients received placebo (mean AUC(0-8 h)= 921.8 +/- 160 and 821.8 +/- 113 ng.h ml(-1), respectively). Four hours after administration of donepezil HCl in PD patients, AUC(0-4 h), C(max) and C(ss) of levodopa were higher than when PD patients received placebo (P < 0.05). Eight hours after donepezil HCl, however, only C(max) and t(max) were observed to change compared with when PD patients received placebo (mean C(max) = 2652 +/- 429 and 2077 +/- 276 ng ml(-1), respectively; mean t(max) = 1.7 +/- 0.4 and 2.9 +/- 0.5 h, respectively; P< or = 0.05). The number of PD patients who experienced at least one adverse event during the study (13/25) was higher when they received donepezil HCl than when they received placebo (5/25), but was the same as healthy subjects who received donepezil HCl only (13/26). There were no significant differences in change from baseline on the UPDRS motor examination parameters in PD patients when they took donepezil HCl and when they took placebo. CONCLUSIONS: No clinically significant drug-drug interactions between donepezil HCl and levodopa/carbidopa were observed at steady state. The small changes in the pharmacokinetics of levodopa did not result in any change in motor symptoms. Co-administration of the two drugs led to a small increase in adverse events compared with administration of levodopa/carbidopa alone in PD patients. These adverse events, however, were consistent with donepezil's cholinomimetic effect, and their incidence was comparable to that observed following the administration of donepezil HCl alone.

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Efficacy and tolerability of donepezil in vascular dementia: positive results of a 24-week, multicenter, international, randomized, placebo-controlled clinical trial.

BACKGROUND AND PURPOSE: Clinical observations suggest that patients with vascular dementia (VaD) may benefit from treatment with cholinesterase inhibitors. This study evaluated the efficacy and safety of donepezil for relieving symptoms of dementia in VaD. METHODS: Patients (n=603; mean age, 73.9 years; 55.2% men) with probable (70.5%) or possible (29.5%) VaD, according to criteria of the National Institute of Neurological Disorders and Stroke (NINDS) and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN), were randomized to 24 weeks of treatment with donepezil 5 mg/d (n=198), donepezil 10 mg/d (5 mg/d for first 28 days; n=206), or placebo (n=199). Analyses were based on the intent-to-treat population. RESULTS: At week 24, both donepezil groups showed significant improvement in cognition versus placebo on the Alzheimer's Disease Assessment Scale-cognitive subscale (mean change from baseline score effect size: donepezil 5 mg/d, -1.90; P=0.001; donepezil 10 mg/d, -2.33; P<0.001). Significant improvements in patients' global function were seen versus placebo at week 24 (observed cases), on the Clinician's Interview-Based Impression of Change-Plus version only for patients on donepezil 5 mg/d (P=0.014), and on the Sum of the Boxes of the Clinical Dementia Rating only for patients on 10 mg/d (P=0.007). Donepezil-treated patients showed significant benefits in activities of daily living over placebo on the Alzheimer's Disease Functional Assessment and Change Scale (mean change from baseline score effect size at week 24: donepezil 5 mg/d, -1.31, P=0.02; donepezil 10 mg/d, -1.31, P=0.02). Donepezil was well tolerated. Withdrawal rates due to adverse events were relatively low (placebo, 11.1%; donepezil 5 mg/d, 11.1%; donepezil 10 mg/d, 21.8%; P=0.005 versus placebo). CONCLUSIONS: These data demonstrate that donepezil is an effective and well-tolerated treatment for VaD and show it may have an important place in the management of this condition.

Activities of Daily Living↗

Concurrent administration of donepezil HCl and sertraline HCl in healthy volunteers: assessment of pharmacokinetic changes and safety following single and multiple oral doses.

AIM: This study evaluated the safety and pharmacokinetics (PK) of donepezil HCl and sertraline HCl when administered separately and in combination. METHODS: This was a randomized, open-label, three-period crossover study. In consecutive dosing periods separated by washout periods of > or = 3 weeks, healthy volunteers received either oral donepezil HCI 5 mg once daily for 15 days, oral sertraline HCl 50 mg once daily for 5 days followed by 10 days of once-daily sertraline HCl 100 mg, or the simultaneous administration of oral donepezil HCl and sertraline HCl. Plasma donepezil and sertraline concentrations were determined by high performance liquid chromatography/mass spectrometry. Safety was evaluated by physical and laboratory evaluations and the monitoring of adverse events (AEs). RESULTS: A total of 19 volunteers (16 male and three female) were enrolled. Three male subjects withdrew from the study prematurely due to AEs (one case of nausea/stomach cramps and one case of eosinophilia during combination treatment, and one upper respiratory tract infection during treatment with sertraline HCl alone). In subjects who completed all three treatment periods (n = 16), the concurrent administration of donepezil HCl and sertraline HCl did not alter the steady-state (day 15) PK parameters of donepezil HCl. A small (< 12%) but statistically significant (P = 0.02) increase in donepezil C(max) was seen after single doses of sertraline HCl and donepezil HCl on day 1 but this was not thought to be clinically meaningful. No significant differences in the t(max) or AUC(0-24 h) of donepezil were observed between the donepezil HCl only or donepezil HCl plus sertraline HCl groups on day 1. No significant changes in sertraline PK parameters were observed either on day 1 (single dose) or on day 15 (steady state) when sertraline HCl was co-administered with donepezil HCl. Generally, the concurrent administration of donepezil HCl and sertraline HCl was well tolerated, with no serious AEs reported during the study. Some digestive system AEs tended to occur more frequently during combination treatment than with either treatment alone, but there was no statistically significant increase in the incidence of any individual AE. The most common AEs during the combination therapy were nausea and diarrhoea, which were rated as mild or moderate in severity. These AEs were also reported during the administration of each drug alone. CONCLUSIONS: The co-administration of once-daily oral donepezil HCl 5 mg for 15 days and once-daily oral sertraline HCl (50 mg for 5 days increased to 100 mg for 10 days) did not result in any clinically meaningful pharmacokinetic interactions, and no unexpected AEs were observed.

Administration, Oral↗

A randomized, double-blind, placebo-controlled study of the efficacy and safety of donepezil in patients with Alzheimer's disease in the nursing home setting.

OBJECTIVES: To evaluate the safety and efficacy of donepezil in the management of patients with Alzheimer's disease (AD) residing in nursing home facilities. DESIGN: Twenty-four-week, randomized, multicenter, parallel-group, double-blind, placebo-controlled trial. SETTING: Twenty-seven nursing homes across the United States. PARTICIPANTS: Two hundred eight nursing home patients with a diagnosis of probable or possible AD, or AD with cerebrovascular disease; mean Mini-Mental State Examination (MMSE) score 14.4; mean age 85.7. MEASUREMENTS: The primary outcome measure was the Neuropsychiatric Inventory-Nursing Home Version (NPI-NH). Secondary efficacy measures were the Clinical Dementia Rating (Nursing Home Version)-Sum of the Boxes (CDR-SB), MMSE, and the Physical Self-Maintenance Scale (PSMS). Safety was monitored by physical examinations, vital signs, clinical laboratory tests, electrocardiograms (ECGs), and treatment-emergent adverse events (AEs). RESULTS: Eighty-two percent of donepezil- and 74% of placebo-treated patients completed the trial. Eleven percent of donepezil- and 18% of placebo-treated patients withdrew because of AEs. Mean NPI-NH 12-item total scores improved relative to baseline for both groups, with no significant differences observed between the groups at any assessment. Mean change from baseline CDR-SB total score improved significantly with donepezil compared with placebo at Week 24 (P < .05). The change in CDR-SB total score was not influenced by age. Differences in mean change from baseline on the MMSE favored donepezil over placebo at Weeks 8, 16, and 20 (P < .05). No significant differences were observed between the groups on the PSMS. Overall rates of occurrence and severity of AEs were similar between the two groups (97% placebo, 96% donepezil). Gastrointestinal AEs occurred more frequently in donepezil-treated patients. In general, AEs were similar in older and younger donepezil-treated patients, with the majority of patients experiencing only AEs that were transient and mild or moderate in severity. Weight loss was reported as an AE more frequently in older patients, although a loss at last visit of >or=7% of screening weight occurred at the same rate in older and younger patients (9% of donepezil- and 6% of placebo-treated patients). No significant differences between groups in vital sign changes, bradycardia, or rates of clinically significant laboratory or ECG abnormalities were observed. CONCLUSION: Patients treated with donepezil maintained or improved in cognition and overall dementia severity in contrast to placebo-treated patients who declined during the 6-month treatment period. The safety and tolerability profile was comparable with that reported in outpatient studies of donepezil. These findings also suggest that advanced age, comorbid illnesses, and high concomitant medication usage should not be barriers to donepezil treatment. Given the apparent improvement in behavior in the placebo group, and the high use of concomitant medications in both groups, the impact of donepezil on behavior in the nursing home setting is unresolved and merits further investigation. In summary, effects on cognition, overall dementia severity, and safety and tolerability findings are consistent with previous findings in outpatients and support the use of donepezil in patients with AD who reside in nursing homes.

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