Clinical profile of donepezil in the treatment of Alzheimer's disease

Cholinergic Modification of Neurogenesis and Gliosis Improves the Memory of AβPPswe/PSEN1dE9 Alzheimer's Disease Model Mice Fed a High-Fat Diet

We previously reported that neuroinflammation contributes to the amnesia of AβPPswe/PSEN1dE9 Alzheimer's disease model mice fed a high-fat diet to induce type-2 diabetes (T2DM-AD mice), but the underlying mechanism for the memory decline remained unclear. Recent studies have suggested that cholinergic modulation is involved in neuroinflammatory cellular reactions including neurogenesis and gliosis, and in memory improvement. In this study, we administered a broad-spectrum cholinesterase inhibitor, rivastigmine (2 mg/kg/day, s.c.), into T2DM-AD mice for 6 weeks, and evaluated their memory performance, neurogenesis, and neuroinflammatory reactions. By two hippocampal-dependent memory tests, the Morris water maze and contextual fear conditioning, rivastigmine improved the memory deterioration of the T2DM-AD mice (n = 8, p < 0.01). The number of newborn neurons in the hippocampal dentate gyrus was 1138±324 (Ave±SEM) in wild-type littermates, 2573±442 in T2DM-AD-Vehicle, and 2165±300 in T2DM-AD-Rivastigmine mice, indicating that neurogenesis was accelerated in the two T2DM-AD groups (n = 5, p < 0.05). The dendritic maturation of new neurons in T2DM-AD-Vehicle mice was severely abrogated, and rivastigmine treatment reversed this retarded maturation. In addition, the hippocampus of T2DM-AD-Vehicle mice showed increased proinflammatory cytokines IL-1β and TNF-α and gliosis, and rivastigmine treatment blocked these inflammatory reactions. Rivastigmine did not change the insulin abnormality or amyloid pathology in these mice. Thus, cholinergic modulation by rivastigmine treatment led to enhanced neurogenesis and the suppression of gliosis, which together ameliorated the memory decline in T2DM-AD model mice.

Modulatory effect of caffeic acid on cholinesterases inhibitory properties of donepezil

Background Donepezil hydrochloride commonly used in the management of Alzheimer's disease (AD), exhibiting its inhibitory effects on acetylcholinesterase and butyrylcholinesterase activity thereby enhance cognitive function. Caffeic acid member of hydroxycinnamic acid is widely present in human diet. This study aims to investigate influence of caffeic acid on acetylcholinesterase and butyrylcholinesterase inhibitory properties of donepezil (in vitro). Methods 5 mg of donepezil was dissolved in 50 mL distilled water while 10 mg of caffeic acid was dissolved in 100 mL distilled water. Therefore, mixtures of samples were prepared as follows: A2=donepezil 0.075 mg/mL+caffeic acid 0.025 mg/mL; A3=donepezil 0.050 mg/mL+caffeic acid 0.050 mg/mL; A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL. All samples were kept in the refrigerator at 4 °C for subsequent analysis. Results The result showed that all the combinations show an inhibitory effect on acetylcholinesterase and butyrylcholinesterase activity in vitro, with the combination A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL had significant (p<0.05) highest inhibitory effect on acetylcholinesterase and butyrylcholinesterase activity in vitro. More so, all the samples were able to prevent pro-oxidants (FeSO4 and sodium nitroprusside [SNP] ) induced lipid peroxidation in rat brain homogenate, with the combination A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL and A3=donepezil 0.050 mg/mL+caffeic acid 0.050 mg/mL had highest inhibitory effect against FeSO4 and SNP induced lipid peroxidation in rat brain homogenate in vitro respectively. Moreover, all the samples exhibit antioxidant properties as typified by their ability to chelate iron (II) ion (Fe2+), hydroxyl radical (OH٭) radical scavenging ability and ferric reducing property (FRAP). Conclusions Therefore, the combination of caffeic acid with donepezil enhances the antioxidant properties of donepezil. The combination of caffeic acid with donepezil could be a therapeutic aid in the management of AD, possibly with fewer side effects of donepezil. Nevertheless, the combination donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL acid look promising.

Impact of nighttime donepezil administration on sleep in the older adult population: A retrospective study

Introduction . Although not definite, studies are finding Alzheimer's disease may be related to loss of cholinergic innervation. In order to impact this loss of function, therapeutic agents have been developed to reduce the breakdown of acetylcholine, a neurotransmitter vital in cognitive processes. Donepezil has been used in Alzheimer's disease for improving cognition. Although the package insert suggests nighttime administration to reduce the instance of daytime side effects, some patients report sleep disturbances.

Methods . Patient charts at the Tallahassee Memorial Healthcare Neuroscience Center (TMH-NSC) were reviewed. Charts of those patients who met the inclusion criteria were used to determine the correlation between night time administration of donepezil and sleep disturbances.

Results . A total of 186 patient charts were analyzed. Of those 186, 103 of the patients were taking donepezil as directed in the package labeling, at night time. Nearly half (47.6%) of the patients taking donepezil at night reported night time disturbances (NTD) and only 21 of the 83 patients taking donepezil in the morning reported NTD.

Conclusion . This retrospective study showed that taking donepezil at night may be associated with sleep disturbances. Although labeling suggests administration in the evening, should NTDs occur, changing the medication administration to the morning should be explored before switching therapeutic agents.

Ergothioneine and melatonin attenuate oxidative stress and protect against learning and memory deficits in C57BL/6J mice treated with D-galactose

Male C57BL/6J mice treated with D-galactose (DG) were used to examine the effects of ergothioneine (EGT), melatonin (MEL), or their combination (EGT+MEL) on learning and memory abilities. The mice were divided into five groups and injected subcutaneously with DG (0.3 mL of 1% DG/mouse) except for group 1 (normal controls). Group 3 was orally supplemented with EGT [0.5 mg/kg body weight (bw)], group 4 with MEL (10 mg/kg bw, p.o.), and group 5 with EGT+MEL. EGT and MEL were provided daily for 88 days, while DG was provided between days 7 to 56. Active avoidance task and Morris water-maze task were used to evaluate learning and memory abilities. DG treatment markedly increased escape latency and decreased the number of avoidance in the active avoidance test, whereas EGT and MEL alone significantly improved the performance. DG also impaired the learning and memory abilities in the water-maze task, and EGT and MEL alone also significantly improved the performance. EGT+MEL produced the strongest effects in both tasks. EGT and MEL alone markedly decreased β-amyloid protein accumulation in the hippocampus and significantly inhibited lipid peroxidation and maintained glutathione/glutathione disulfide ratio and superoxide dismutase activity in brain tissues of DG-treated mice. MEL alone completely prevented the rise in brain acetylcholine esterase activity induced by DG, whereas EGT and EGT+MEL were only partially effective. Overall, EGT, MEL, and, in particular, the combination of EGT and MEL effectively protect against learning and memory deficits in C57BL/6J mice treated with DG, possibly through attenuation of oxidative damage.

Ginsenosides Rg5 and Rh3 protect scopolamine-induced memory deficits in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng (family Araliaceae) is traditionally used as a remedy for cancer, inflammation, stress and aging.

AIM OF STUDY

To explore whether ginsenosides Rg5 and Rh3, the main constituents of heat-processed ginseng (the root of Panax ginseng), could protect memory deficit.

MATERIALS AND METHODS

We isolated ginsenosides Rh3 and Rg5 from heated-processed ginseng treated with and without human feces, respectively. Then we investigated their protective effects on memory impairment using the passive avoidance, Y-maze and Morris water maze tasks in mice. Memory deficit was induced in mice by the intraperitoneal injection of scopolamine.

RESULTS

Ginsenosides Rg5 or Rh3 increased the latency time reduced by scopolamine in passive avoidance test. Treatment with ginsenoside Rg5 or Rh3 significantly reversed the lowered spontaneous alteration induced by scopolamine in Y-maze task. Ginsenoisde Rg5 or Rh3 (10 mg/kg) significantly shortened the escape latencies prolonged by treatment with scopolamine on the last day of training trial sessions in Morris water maze task. Furthermore, ginsenosides Rg5 and Rh3 inhibited acetylcholinesterase activity in a dose-dependent manner, with IC50 values of 18.4 and 10.2 μM, respectively. The inhibitory potency of ginsenoside Rh3 is comparable with that of donepezil (IC50=9.9 μM). These ginsenosides also reversed hippocampal brain-derived neurotrophic factor (BDNF) expression and cAMP response element-binding protein (CREB) phosphorylation reduced by scopolamine. Of them, ginsenoside Rh3 more potently protected memory deficit.

CONCLUSIONS

Ginsenoside Rg5 and its metabolite ginsenoside Rh3 may protect memory deficit by inhibiting AChE activity and increasing BDNF expression and CREB activation.

Lancemaside A isolated from Codonopsis lanceolata and its metabolite echinocystic acid ameliorate scopolamine-induced memory and learning deficits in mice

The rhizome of Codonopsis lanceolata (family Campanulaceae), which contains lancemaside A as a main constituent, has been used as herbal medicine to treat inflammation, insomnia, and hypomnesia. Lancemaside A and echinocystic acid, which is its metabolite by intestinal microflora, potently inhibited acetylcholinesterase activity in a dose-dependent manner, with IC₅₀ value 13.6 μM and 12.2 μM, respectively. Its inhibitory potency is comparable with that of donepezil (IC₅₀=10.9 μM). Lancemaside A and echinocystic acid significantly reversed scopolamine-induced memory and learning deficits on passive avoidance task. Lancemaside A orally administered 5h before treatment with scopolamine reversed scopolamine-induced memory and learning deficits more potently than one orally administered 1h before. Echinocystic acid more potently reversed it than lancemaside A. Lancemaside A and echinocystic acid significantly reversed scopolamine-induced memory and learning deficits on the Y-maze and Morris water maze tasks. Lancemaside A and echinocystic acid also increased the expression of brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element binding protein (p-CREB). Based on these findings, orally administered lancemaside A may be metabolized to echinocystic acid, which may be absorbed into the blood and ameliorate memory and learning deficits by inhibiting AChE activity and inducing BDNF and p-CREB expressions.

Structural requirement of fibrogenic laminin-derived peptide A119 (LSNIDYILIKAS) for amyloid-like fibril formation and cellular activity

A119 peptide (LSNIDYILIKAS), derived from the mouse laminin α1 chain sequence (residues 1321-1332), promotes cell attachment, neurite outgrowth, and amyloid-like fibril formation. In this study, we evaluated the structural requirements of A119 for biological activities and amyloid-like fibril formation. The attachment of the cell to A119 was inhibited by heparin, and using syndecan- and glypican-overexpressed cells, it was determined that A119 specifically binds to syndecans. We also evaluated the critical residues for A119 activities using a set of alanine-substituted peptides. Cell attachment activity was significantly reduced in the Leu(1)-, Ser(2)-, Asn(3)-, Ile(4)-, Ile(7)-, Ile(9)-, and Lys(10)-substituted alanine peptides. Residues Ile(4), Ile(7), Ile(9), and Lys(10) were important for neurite outgrowth activity. Congo red staining and electron microscopic examination revealed that the Ile(4), Ile(7), Ile(9), and Ser(12) residues of A119 were required for amyloid-like fibril formation. These data suggest that the Ile residues are critical for the amyloid-like fibril formation, cell attachment, and neurite outgrowth activity of A119. Furthermore, an enantiomer of A119 showed similar amyloid-like fibril formation and increased levels of cell attachment and FAK signal transduction. These findings shed light on the mechanism of amyloid-like fibril formation and demonstrate a relationship between the ability to form amyloid-like fibrils and cell behavior.

Lactobacillus pentosus var. plantarum C29 protects scopolamine-induced memory deficit in mice

AIMS

In the preliminary study, kimchi, a traditional food fermented with Chinese cabbage, protected scopolamine-induced mouse memory deficit in passive avoidance test. Therefore, we screened protective ingredients, particularly lactic acid bacteria, from Chinese cabbage kimchi against scopolamine-induced memory deficit in mice.

METHODS AND RESULTS

Lactic acid bacteria, isolated from Chinese cabbage kimchi, were identified by 16S rDNA sequence analysis, G+C content and cellular fatty acid composition and sugar fermentation test. Memory deficit was induced in mice by intraperitoneally injecting with scopolamine. Kimchi, particularly its supernatant, protected scopolamine-induced memory deficit in mice in passive avoidance test. Of kimchi ingredients, a lactic acid bacterium, strain C29, potently protected scopolamine-induced memory deficit in mice. C29 was a gram-positive, catalase-negative, anaerobic and non-motile rod. Its pylogenetic property was near to Lactobacillus pentosus (99%) and Lact. plantarum (99%). However, C29 fermented inulin and L-rhamnose and grew in pH 3 and at 45°C in contrast with Lact. pentosus and Lact. plantarum. Therefore, it named to be Lact pentosus var. plantarum C29. The strain C29 protected scopolamine-induced memory deficit in Y-maze and Morris water maze tests. Furthermore, C29 increased hippocampal BDNF and p-CREB expressions, which were reduced by scopolamine.

CONCLUSION

Lactobacillus pentosus var. plantarum C29 may protect memory deficit by inducing BDNF and p-CREB expressions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lactic acid bacteria, such as Lact pentosus var. plantarum C29, may prevent memory deficit and its contained fermented foods may be beneficial for dementia.

Schizandrin, an antioxidant lignan from Schisandra chinensis, ameliorates Aβ1-42-induced memory impairment in mice

In the present study, we examined the effect of schisandrin (SCH) of Schisandra chinensis on the amyloid-beta(1-42)- (Aβ(1-42)-) induced memory impairment in mice and elucidated the possible antioxidative mechanism. Mice were intracerebroventricular (i.c.v.) injected with the aggregated Aβ(1-42) and then treated with SCH (4, 12, and 36 mg/kg body weight) or donepezil (DPZ), a reference drug (0.65 mg/kg) by intragastric infusion for 14 days. Noncognitive disturbances and cognitive performance were evaluated by locomotor activity test, Y-maze test, and water maze test. Antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and levels of malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG) within the cerebral cortex and hippocampus of mice were measured to elucidate the mechanism. Our results showed that SCH significantly improved Aβ(1-42)-induced short-term and spatial reference memory impairments in Y-maze test and water maze test. Furthermore, in the cerebral cortex and hippocampus of mice, SOD and GSH-px activities, GSH level, and GSH/GSSG ratio were increased, and levels of MDA and GSSG were decreased by the treatment of SCH. These results suggest that SCH is a potential cognitive enhancer against Alzheimer's disease through antioxidative action.

Kalopanaxsaponins A and B isolated from Kalopanax pictus ameliorate memory deficits in mice

The stem-bark of Kalopanax pictus (KP, family Araliaceae), which contains triterpenoid saponins, has been shown to exhibit anticarcinogenic, antiinflammatory, antirheumatoid and antidiabetic activities. In a preliminary study, a KP methanol extract demonstrated acetylcholinesterase activity in vitro and memory enhancement in scopolamine-treated mice. Therefore, we isolated acetylcholinesterase inhibitors, kalopanaxsaponins A and B, from a KP butanol (BuOH) fraction, measured acetylcholinesterase activity in vitro, and investigated their memory-enhancing effects in a passive avoidance test, Y-maze test and Morris water maze test. These constituents inhibited acetylcholinesterase activity and significantly reversed scopolamine-induced deficits. They also increased brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element binding (p-CREB) protein expression but reduced TNF-α increased by scopolamine. Based on these findings, kalopanaxsaponins A and B may ameliorate memory deficits by inhibiting acetylcholinesterase activity and inducing BDNF and p-CREB expression.

Pharmacokinetic comparison of orally disintegrating and conventional donepezil formulations in healthy Korean male subjects: a single-dose, randomized, open-label, 2-sequence, 2-period crossover study

BACKGROUND

Donepezil is a potent inhibitor of acetylcholinesterase, an enzyme that is targeted in the treatment of Alzheimer's disease.

OBJECTIVE

The purpose of this study was to compare the pharmacokinetic characteristics of orally disintegrating (test) and conventional (reference) donepezil formulations to satisfy the regulatory requirement for marketing.

METHODS

A single-center randomized, single-dose, open-label, 2-way crossover study with a 21-day washout period was conducted in 22 healthy volunteers. Plasma samples for the analysis of donepezil were collected up to 240 hours after drug administration. Participants received either reference or test drug formulation of 10 mg donepezil in the first period and the alternative formulation in the second period. Plasma concentrations of donepezil were determined by validated high-performance liquid chromatography coupled to tandem mass spectrometry detection. Pharmacokinetic parameters, including C(max) and AUC, were determined by noncompartmental analysis. ANOVA was carried out using log-transformed C(max) and AUC, and the mean ratios and their 90% CIs were calculated. The safety profiles and tolerabilities of the 2 formulations were also assessed based on laboratory tests, 12-lead ECGs, vital signs, and physical examinations.

RESULTS

Of the 22 participants initially enrolled, 18 healthy Korean participants completed both treatment periods. Four subjects did not complete both treatments: 3 subjects withdrew consent for personal reasons, and 1 subject experienced adverse events. No significant differences in pharmacokinetic parameters between the 2 formulations were observed. The mean (SD) age, height, and weight of the participants were 25.8 (4.1) years, 173.6 (5.7) cm, and 68.9 (7.8) kg, respectively. The mean (SD) C(max), AUC(last), and AUC(inf) for the reference formulation were 33.26 (6.58) ng/mL, 1521.69 (344.04) ng × h/mL, and 1691.46 (443.05) ng × h/mL, respectively. Corresponding values for the test formulation were 34.23 (6.79) ng/mL, 1554.33 (390.23) ng × h/mL, and 1718.27 (447.03) ng × h/mL, respectively. The median T(max) was 2 hours (range, 1-3 hours) for the reference and test formulations. The geometric mean ratios (90% CI) between the 2 formulations of donepezil were 102.9 (96.8-109.5) for C(max), 102.3 (96.1-108.9) for AUC(last), and 101.6 (95.4-108.2) for AUC(0-∞), respectively. During the study, 15 and 14 adverse events were reported for the reference and test formulations, respectively, and all were transient, mild, and resolved during the treatment period. These adverse events included 7 cases of nausea, 3 cases of headache, and 1 case each of dizziness, vomiting, chills, and sweating. All adverse events were considered related to the study drugs.

CONCLUSION

This study found that the test and reference formulations met the regulatory criteria for pharmacokinetic equivalence in these fasting healthy Korean male subjects. Both donepezil formulations appeared to be generally well tolerated.

Mangiferin ameliorates scopolamine-induced learning deficits in mice

The aim of this study was to evaluate the effects of Anemarrhena asphodeloides BUNGE (AA) on cholinergic memory deficits in mice. This agent has previously been used as an antipyretic, anti-inflammatory, anti-diabetic, and antidepressant in traditional Chinese medicine. Mangiferin was isolated from AA and showed a dose-dependent inhibition of acetylcholinesterase (AChE) activity (IC(50) value, 62.8 microM). Cholinergic dysfunction was induced in mice by administering scopolamine, and the animals were then tested using the passive avoidance test as well as the Morris water maze test. Mangiferin (20 mg/kg, p.o.) significantly reversed scopolamine-induced deficits in the passive avoidance test, and also improved escape latencies in training trials and increased swimming times in the Morris water maze test (p<0.05). Mangiferin also reduced acetylcholine and tumor necrosis factor (TNF)-alpha levels induced by scopolamine in mice brain (p<0.05) and inhibited nuclear factor (NF)-kappaB activation in scopolamine or TNF-alpha-stimulated BV-2 microglial cells. These results suggest that mangiferin can improve long-term cholinergic memory deficits by AChE inhibition or cholinergic receptor stimulation and inhibition of NF-kappaB activation.

Small molecule blockers of the Alzheimer Abeta calcium channel potently protect neurons from Abeta cytotoxicity

Alzheimer's disease (AD) is a common, chronic neurodegenerative disease that is thought to be caused by the neurotoxic effect of the Amyloid beta peptides (Abeta). We have hypothesized that the intrinsic Abeta calcium channel activity of the oligomeric Abeta polymer may be responsible for the neurotoxic properties of Abeta, and that Abeta channel blockers may be candidate AD therapeutics. As a consequence of a rational search paradigm based on the model structure of the Abeta channel, we have identified two compounds of interest: MRS2481 and an enatiomeric species, MRS2485. These are amphiphilic pyridinium salts that both potently block the Abeta channel and protect neurons from Abeta toxicity. Both block the Abeta channel with similar potency (approximately 500 nM) and efficacy (100%). However, we find that inhibition by MRS2481 is easily reversible, whereas inhibition by MRS2485 is virtually irreversible. We suggest that both species deserve consideration as candidates for Alzheimer's disease drug discovery.

Combination of rimonabant and donepezil prolongs spatial memory duration

The observations that the cannabinoid(1)(CB(1)) receptor antagonist/inverse agonist, rimonabant, and the selective noncompetitive inhibitor of acetylcholinesterase (AChE), donepezil, improve performance in a variety of animal memory models, suggest that these neurochemical systems play integral roles in cognition. The present study tested whether each of these agents administered alone or in combination will prolong the duration of spatial memory. Rats were trained in a two-phase radial-arm maze procedure, consisting of acquisition and retrieval tests, which were separated by an 18 h delay. Each drug was administered 30 min before the acquisition phase, immediately after the acquisition phase, or 30 min before the retrieval test to assess acquisition/consolidation, consolidation, and retrieval mnemonic processes, respectively. Rimonabant or donepezil administered before the acquisition phase, but not immediately after acquisition or before retrieval, led to a significant decrease in the number of errors committed during the retrieval test. Combined administration of subthreshold doses of rimonabant and donepezil that had no discernable effects on performance when given alone, enhanced memory. These results taken together demonstrate that the delay radial-arm maze task is sufficiently sensitive to detect memory enhancing effects of these drugs. Moreover, these findings suggest that combined administration of subthreshold doses of rimonabant and donepezil can improve memory and may represent a novel approach to treat cognitive deficits associated with neurodegenerative disorders.

Nodakenin, a coumarin compound, ameliorates scopolamine-induced memory disruption in mice

Nodakenin is a coumarin compound initially isolated from the roots of Angelica gigas. In the present study, we investigated the effects of nodakenin on learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Nodakenin (10 mg/kg, p.o.) administration significantly reversed scopolamine-induced cognitive impairments in the passive avoidance test and the Y-maze test (P<0.05), and also reduced escape latency during training in the Morris water maze test (P<0.05). Moreover, swimming times and distances within the target zone of the Morris water maze were greater in the nodakenin-treated group than in the scopolamine-treated group (P<0.05). In an in vitro study, nodakenin was found to inhibit acetylcholinesterase activity in a dose-dependent manner (IC(50)=84.7 microM). In addition, nodakenin was also found to inhibit acetylcholinesterase activity for 6 h in an ex-vivo study. These results suggest that nodakenin may be a useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, via the enhancement of cholinergic signaling.

A 24-week, double-blind, placebo-controlled study of three dosages of Cerebrolysin in patients with mild to moderate Alzheimer's disease

Cerebrolysin (Cere) is a compound with neurotrophic activity shown to be effective in Alzheimer's disease in earlier trials. The efficacy and safety of three dosages of Cere were investigated in this randomized, double-blind, placebo-controlled, study. Two hundred and seventy-nine patients were enrolled (69 Cere 10 ml; 70 Cere 30 ml; 71 Cere 60 ml and 69 placebo). Patients received iv infusions of 10, 30, 60 ml Cere or placebo 5 days/week for the first 4 weeks and thereafter, two iv infusions per week for 8 weeks. Effects on cognition and clinical global impressions were evaluated 4, 12 and 24 weeks after the beginning of the infusions using the CIBIC+ and the modified Alzheimer's Disease Assessment Scale (ADAS)-cog. At week 24, significant improvement of cognitive performance on the ADAS-cog (P=0.038) and global function (CIBIC+; P>0.001) was observed for the 10 ml dose. The 30 and 60 ml doses showed significant improvement of the global outcome but failed to show significant improvement of cognition. The results are consistent with a reversed U-shaped dose-response relationship for Cere. The percentage of patients reporting adverse events was similar across all study groups. Cere treatment was well tolerated and led to significant, dose-dependent improvement of cognition and global clinical impression.

Effects of selegiline alone or with donepezil on memory impairment in rats

Selegiline, a monoamine oxidase-B inhibitor, is reported to improve memory and learning in dementia of Alzheimer's type. However, only a few studies have reported its use in animal models. Here, we evaluated the effects of selegiline only or its combined use with donepezil, a selective acetylcholinesterase inhibitor on memory impairment, using a Morris water maze. Selegiline dose-dependently attenuated ethylcholine aziridinium ion-induced memory impairment. Co-administration of selegiline and donepezil, at doses that do not exert efficacy individually, significantly ameliorated scopolamine+p-chlorophenylalanine-induced memory deficits. These results suggest that selegiline improves memory impairment mediated by the cholinergic system, and provide evidence of the usefulness of co-treatment with selegiline and donepezil for treating spatial deficits in dementia.

Long-Term Treatment of Alzheimer Disease

During the past 20 years, research on Alzheimer disease (AD) and other dementias has increased our understanding of these disorders and has opened doors to new methods of treatment. Acetylcholinesterase inhibitors (AChEIs) have been successful in reducing symptoms in patients with mild-to-moderate AD and led to the US Food and Drug Administration's approval of four AChEIs for the treatment of AD. Although these agents are approved for only mild-to-moderate AD, and the available data for most of them are from trials of only 6 months' duration, long-term studies suggest that the benefits of AChEI treatment can endure for up to 4 years. A common pattern of response to treatment is initial improvement in cognition, followed by maintenance of cognitive gains above baseline for up to 1 year. Generally there is a decline in cognition to below baseline levels after approximately 1 year of treatment, but the level of cognition remains above that predicted for those not receiving pharmacologic treatment. Furthermore, long-term studies suggest that early diagnosis and treatment with AChEIs yield better long-term outcomes. Patients who received continuous pharmacologic treatment from the outset generally had better long-term outcomes than those who received placebo in the double-blind phase of these trials.

The effect of donepezil on sedation and other symptoms in patients receiving opioids for cancer pain: a pilot study

Opioid-induced sedation is a major complication in patients with cancer pain. This study assessed the effectiveness of donepezil in opioid-induced sedation and related symptoms in patients with cancer pain. Twenty-seven patients who were receiving strong opioids for pain and reported sedation were enrolled. Donepezil 5 mg was given every morning for 7 days. Changes between baseline and Day 7 in sedation, pain, fatigue and other symptoms were evaluated using the Edmonton Symptom Assessment Scale. Fatigue was also measured using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue). Overall usefulness of donepezil was measured by the patient at the end of the study. In 20 evaluable patients, sedation, fatigue, anxiety, well-being, depression, anorexia and problems with sleep were significantly improved. Side effects included nausea, vomiting, diarrhea, muscle and abdominal cramps, and anorexia. Overall, however, the treatment was well tolerated. Donepezil appears to improve sedation and fatigue in patients receiving opioids for cancer pain. Randomized controlled trials of this agent are justified.

Update on Alzheimer drugs (donepezil)

BACKGROUND

Several clinical trials have been conducted over a period of many years reporting the benefits of donepezil for Alzheimer disease (AD) patients.

REVIEW SUMMARY

Randomized, double-blind, placebo-controlled stud-ies of 3-6 months' duration have demonstrated significant benefits for 5mg/D and 10 mg/D of donepezil compared with placebo. The results include benefits for cognition, activities of daily living, and abnormal behaviors associated with AD. The benefits are independently detectable by clinicians based upon direct patient assessment with input from a caregiver. Populations studied include mild-to-moderate AD patients, moderate-to-severe AD patients, nursing home patients, and outpatients. Open label studies that took place after the double-blind phase and 1-year double-blind, placebo-controlled trials demonstrated that benefits persist for more than a year. Adverse event (AE) profiles, generated in studies that used a 1-week forced dose titration, show a low incidence of primarily cholinegic AEs such as nausea and diarrhea. There are no significant laboratory AEs or drug interactions. Recent studies have assessed the benefits of donepezil inpatients with ischemic vascular dementia, mild cognitive impairment, and other cognitive disorders.

CONCLUSIONS

Donepezil benefits AD patients by improving, stabilizing, or retarding decline of the cognitive, functional, and possibly behavioral features of the disease. The duration of benefits is not known but extends beyond 1 year. The drug is safe and well tolerated.

Donepezil as add-on treatment of psychotic symptoms in patients with dementia of the Alzheimer's type

Traditionally, the neuropsychiatric symptoms of Alzheimer's disease (AD) have been managed with neuroleptics or benzodiazepines, which have serious side effects. Preliminary observations suggest the possible value of cholinesterase inhibitors in the amelioration of psychotic symptoms in patients with dementia of the Alzheimer's type, dementia with Lewy bodies, and in patients with Parkinson's disease. Twelve inpatients with AD with psychotic symptoms and lack of improvement of their delusions/hallucinations during perphenazine treatment (8 mg/day) for 3 weeks received random open-label donepezil 5 mg daily in addition to an ongoing treatment of 8 mg/day perphenazine or 16 mg/day perphenazine. Assessments conducted at baseline and after weeks 2 and 4 included the Mini-Mental State Examination, the Global Deterioration Scale, the Positive and Negative Symptoms Scale, and the Clinical Global Impressions scale. Frequency of extrapyramidal symptoms was measured according to the Abnormal Involuntary Movement Scale. The donepezil-perphenazine group exhibited substantially greater and clinical improvements in mental state. At the end of the trial (4 weeks), Positive and Negative Symptoms Scale scores revealed significant differences between both groups (p = 0.006). The Clinical Global Impressions scale and the Mini-Mental State Examination scores also showed significant differences between the donepezil-perphenazine group and the perphenazine group (p = 0.028 and p = 0.027 respectively). No significant differences were found in the Global Deterioration Scale scores. Abnormal Involuntary Movement Scale scores showed a significant deterioration in extrapyramidal symptoms in the perphenazine group compared with the donepezil-perphenazine group (p = 0.016). Donepezil augmentation of neuroleptics may be appropriate for those patients for whom neuroleptic monotherapy either does not lead to symptom remission or is associated with intolerable adverse effects. This was an open-label study and there is need for larger studies with double-blind control and a long-term study design to define the efficacy of donepezil for patients with AD and psychotic symptoms.

Pharmacokinetic and safety assessments of concurrent administration of risperidone and donepezil

Treatment of Alzheimer's disease sometimes uses combinations of drugs because dementia is frequently associated with behavioral symptoms. Risperidone and donepezil are both metabolized through cytochrome P450 2D6 and 3A4, raising the possibility of drug interactions with combination therapy. The objective of this study was to determine whether significant drug interactions occur with concomitant administration of donepezil and risperidone. In an open-label, three-way crossover study, 24 healthy men were randomly assigned to receive 0.5 mg of risperidone twice daily, 5 mg of donepezil once daily, or both drugs for 14 consecutive days, followed by a 21-day washout period. The treatment ratios of AUC and associated 90% confidence intervals (CIs) for risperidone active moiety, defined as risperidone plus 9-hydroxyrisperidone (ratio = 110.2%; 90% CI = 103.7-117.2), and for donepezil (ratio = 97.1%; 90% CI = 90.0-103.6) were within the 80% to 125% of bioequivalence range. The treatment ratios of Cmax and associated 90% CIs for risperidone active moiety (ratio = 114.6%; 90% CI = 107.0-122.8) and for donepezil (ratio = 96.1%; 90% CI = 90.0-102.6) were also within the bioequivalence range. Therefore, no significant pharmacokinetic differences occurred in either risperidone active moiety or donepezil when given alone or in combination. Adverse events (predominantly headache, nervousness, and somnolence) were minor and comparable for all treatment groups. The results indicate that no clinically meaningful drug interactions occurred between risperidone 1 mg daily and donepezil 5 mg daily at steady state, and therefore no dosage adjustment is required when both drugs are combined with the dosage regimen studied. Additional investigations are warranted to determine the potential for interactions in elderly patients with dementia who may eliminate risperidone and donepezil more slowly and thus be more vulnerable to clinical drug interactions than the young healthy subjects examined in this study.

Current drugs and future hopes in the treatment of Alzheimer's disease

In spite of several years of experience with the use of cholinesterase inhibitors for treatment of symptoms of Alzheimer's disease their influence on disease progression remains still unclear. New cholinesterase inhibitors should provide an additional neuroprotective activity, because only substances which stop neuronal death can influence disease progression. New treatment strategies are focusing on amyloid processing, preventing the occurrence of toxic A beta(1-42) peptide. These procedures include the vaccination trials, but their clinical usefulness has to be proven. Also strategies focussing on neurofibrillary pathologies should be explored in detail. Drug development for Alzheimer's disease should include all pathological events associated with neurodegeneration, like oxidative stress, neuroinflammation or disturbances in growth factor signaling. Abnormal protein aggregation as a common feature of different neurodegenerative diseases might also be a promising drug target. Beside beta sheet breakers directed against beta-amyloid deposition the endogenous protein beta-synuclein or derivatives of it might be able to counteract aggregation of alpha-synuclein as well as of amyloid beta protein. Interaction with alpha-synuclein deserves special attention because it might be an early step of synaptic degeneration. Due to the complexity of the disease combination of different drugs might be the most promising way to go. The parallel development of early biological markers should enable intervention in pre-symptomatic disease stages.

A 24-week, double-blind, placebo-controlled trial of donepezil in patients with Down syndrome and Alzheimer's disease--pilot study

BACKGROUND

Donepezil Hydrochloride (Aricept) is a selective anticholinesterase inhibitor developed for the treatment of Alzheimer's disease (AD). This study investigated the safety and efficacy of the drug to treat Down syndrome (DS) adults with mild to moderate AD.

METHOD

This was a 24-week, double blind, placebo controlled, parallel-group trial. Patients were randomized to receive placebo or donepezil (5 mg per day during the first four weeks, and then 10 mg per day thereafter). Primary efficacy was measured using the Dementia Scale for Mentally Retarded Persons (DMR), and secondary efficacy was measured using the Severe Impairment Battery (SIB), Neuropsychiatric Inventory (NPI) and by the Adaptive Behavior Scale (ABS).

RESULTS

A total of 30 DS patients with AD entered the study of which 27 were included in the subsequent data analysis. The donepezil group had non-statistically significant reduction in deterioration in DMR, SIB, and ABS mean scores relative to the placebo group. However NPI scores showed less improvement in the donepezil group when compared to the placebo group. Fifty percent of subjects in the donepezil group showed improvement in mean DMR scores at the end point compared to baseline, when compared to 31% on placebo. There were no life threatening adverse effects associated with treating adults with DS with donepezil. A number of side-effects did occur including diarrhoea, insomnia, fatigue, and nausea.

CONCLUSION

Donepezil Hydrochloride administered once a day appears to be generally well tolerated and safe in DS adults who have AD. There is some possible efficacy in the treatment of symptoms of mild to moderate Alzheimer's disease in this population, although the sample size of this study was too small for statistical significance. It is recommended that donepezil, with the appropriate precautions, should be considered for the treatment of AD in adults with DS as deemed by a specialist.

Donepezil in the treatment of opioid-induced sedation: report of six cases

Donepezil, an oral acetylcholinesterase inhibitor approved for the treatment of Alzheimer's disease, was given to 6 cancer pain patients having sedation related to the analgesic use of opioids. Each patient was taking more than 200 mg of oral morphine equivalents per day, and several were receiving complex analgesic regimens consisting of multiple adjuvant medications. Sedation improved at least moderately in 5 of the patients and mildly in 1 after they began taking donepezil. Patients reported a decrease in episodes of spontaneous sleeping during the day, fewer myoclonic twitches, improved daily function and greater social interaction. Several also reported improved sleep at night. Analgesia was not compromised by the use of donepezil, and in some cases it appeared improved. Donepezil may be a valuable alternative to psychostimulants in the treatment of opioid-induced sedation. A prospective controlled trial comparing the treatment effects of psychostimulants and donepezil on patients having opioid-induced sedation is underway.

Review of outcome measurement instruments in Alzheimer's disease drug trials: introduction

This article introduces a four-part series on outcome scales used in Alzheimer's disease drug trials. First, it discusses the division of scales into four domains: cognition, functional ability/quality of life, behavior/mood, and global. Within each domain, the shortcomings of existing literature reviews are outlined, and the need for a more coherent view of the psychometric properties of the scales is emphasized. Second, the key concepts of reliability, validity, and responsiveness to change are defined and explained. This explanation also provides an overview of the statistical techniques used to assess measurement properties. Finally, the methods used to select the scales for review in the subsequent articles are explained, and each article is briefly introduced.

Donepezil dose-dependently inhibits acetylcholinesterase activity in various areas and in the presynaptic cholinergic and the postsynaptic cholinoceptive enzyme-positive structures in the human and rat brain

In the symptomatic treatment of mild to moderately severe dementia associated with Alzheimer's disease, donepezil (E2020) has been introduced for the inhibition of acetylcholinesterase activity in the human brain. However, there is no morphological evidence as to how this chemical agent affects the acetylcholinesterase-positive structures in the various areas of the human and the rat CNS. This study demonstrates by histochemical means that donepezil exerts a dose-dependent inhibitory effect in vitro on acetylcholinesterase activity. The most sensitive areas were the cortex and the hippocampal formation. Within the different layers of the cortex, the cholinoceptive acetylcholinesterase-positive postsynaptic pyramidal cell bodies were more sensitive than the presynaptic cholinergic axonal processes. In the cortex, the cell body staining was already abolished by even 2 x 10(-8)M donepezil, whereas the axonal staining could be eliminated only by at least 5 x 10(-8)M donepezil. In the hippocampus, the axonal acetylcholinesterase reaction end-product was eliminated by 5 x 10(-7)M donepezil. The most resistant region was the putamen, where the staining intensity was moderately reduced by 1 x 10(-6)M donepezil. In the rat brain, the postsynaptic cholinoceptive and presynaptic cholinergic structures were inhibited by nearly the same dose of donepezil as in the human brain. These histochemical results provide the first morphological evidence that, under in vitro circumstances, donepezil is not a general acetylcholinesterase inhibitor in the CNS, but rather selectively affects the different brain areas and, within these, the cholinoceptive and cholinergic structures. The acetylcholinesterase staining in the nerve fibers (innervating the intracerebral blood vessels of the human brain and the extracerebral blood vessels of the rat brain) and at the neuromuscular junction in the diaphragm and gastrocnemius muscle of rat, was also inhibited dose dependently by donepezil. It is concluded that donepezil may be a valuable tool with which to influence both the pre- and the postsynaptic acetylcholinesterase-positive structures in the human and rat central and peripheral nervous systems.

Donepezil for Alzheimer's disease: pharmacodynamic, pharmacokinetic, and clinical profiles

Donepezil was developed in order to overcome the disadvantages of physostigmine and tacrine. Its use is based on the cholinergic hypothesis. Donepezil is a piperidine-based, reversible acetylcholinesterase inhibitor, that is chemically unrelated to other cholinesterase inhibitors. It was developed for the symptomatic treatment of Alzheimer's disease (AD). Donepezil is highly selective for acetylcholinesterase with a significantly lower affinity for butyrylcholinesterase, which is present predominantly in the periphery. Phase I and II clinical trials demonstrated donepezil's favorable pharmacokinetic, pharmacodynamic and safety profile. There is no need to modify the dose of donepezil in the elderly or in patients with renal and hepatic failure. Pivotal phase-III trials in the US, European countries, and Japan showed that donepezil significantly improved cognition and global function in patients with mild to moderate AD. In long-term trials, donepezil maintained cognitive and global function for up to 1 year prior to the resumption of gradual deterioration. Donepezil is generally well tolerated; most of its adverse events are mild, transient and cholinergic in nature. Donepezil produces no clinically significant changes in laboratory parameters, including liver function. The drug is approved for the treatment of mild to moderate Alzheimer's disease, but donepezil therapy does not have to be discontinued if a patient continues to deteriorate. Possible new indications for donepezil in psychiatric and neurologic diseases, other than AD, include dementia with Lewy bodies, brain injury, attention deficit hyperactivity, multiple sclerosis, Down's syndrome, delirium, mood disorders, Huntington's disease and sleep disorders.

Current and future clinical trials for Alzheimer's disease: evolving ethical concerns

1. An increase in the cases of Alzheimer's disease, primarily consequent to the rapid growth of the elderly population necessitates the enhanced pace of anti-dementia drug development and an increase in clinical trials. Clinical trials with persons with dementia, however, present with a number of ethical concerns that need to be anticipated and analyzed. 2. The present review first discusses some of the on-going and possible future experimental approaches to anti-dementia drug development. 3. Some of the ethical concerns raised by anti-dementia drug research with human subjects are then examined. A few preliminary recommendations for future directions are proposed. It is important to anticipate issues of ethical and social concern and establish forums for appropriate bioethical analysis.

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.

Approach towards an integrative drug treatment of Alzheimer's disease

At present pharmacotherapy of Alzheimer's disease (AD) is limited to acetylcholinesterase inhibitors. These drugs produce small, but consistent improvements of memory and global function, some are also positively influencing activities of daily living. This therapeutic approach neglects the complexity of AD and the fact that most of the degenerating neurons are not cholinergic. Acetylcholinesterase inhibitors are symptomatic drugs, with no influence on disease progression. There is a need for disease modifying compounds, or preventive drugs. Data are indicating that vitamin E has some ability to influence the disease progression. The potency of non-steroidal anti-inflammatory drugs (NSAIDs) or estrogen as preventive agents has to be explored further in prospective clinical studies. The initial hope in the use of naturally occurring neurotrophic factors, like nerve growth factor, to rescue cholinergic neurons from degeneration and to restore cognitive function has been disappointed in first, small clinical studies. The peptidergic drug Cerebrolysin exhibiting neurotrophic stimulation, neuroimmunotrophic regulation and induction of BBB glucose transporter expression, might be able to address the pathological changes of AD at different levels simultaneously. In addition to an impressive preclinical database, results from 3 placebo-controlled, double-blind studies demonstrate significant improvements of cognitive performance, global function and activities of daily living in AD patients. In all studies persisting improvements, up to 6 months after drug withdrawal, indicate a powerful disease modifying activity.