Strategies for continued successful treatment of Alzheimer's disease: switching cholinesterase inhibitors

Green synthesis of gold nanaoparticles using Delphinium Chitralense tuber extracts, their characterization and enzyme inhibitory potential

Green synthesis has been introduced as an alternative to chemical synthesis due to the serious consequences. Metal nanoparticles synthesized through green approach have different pharmaceutical, medical and agricultural applications. The present study followed a green and simple route for the preparation of potentially bioactive gold nanoparticles (Au NPs). Au NPs were prepared via green synthesis approach using crude basic alkaloidal portion of the tuber of Delphinium chitralense. The green synthesized Au NPs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) fourier transform infrared (FTIR), and UV-Visible spectrophotometer. Morphological analysis shows that Au NPs have cubic geometry with different sizes. UV-Vis spectroscopic analysis confirmed the synthesis of Au NPs while XRD proved their pure crystalline phase. The Au NPs showed promising dose dependent inhibition of both AChE and BChE as compared to the crude as well as standard drug.

Effectiveness of the 10 cm2 Rivastigmine Patch in Taiwanese Patients with Mild-to-Moderate Alzheimer's Dementia: A 48-Week Real-World Observational Study

Introduction

The current study aimed to provide data on the effectiveness of the 10 cm² rivastigmine patch in patients with Alzheimer’s disease (AD) in a real-world setting in Taiwan.

Methods

This was a 48-week, single-arm, open-label, observational, and post-marketing study conducted across seven centers in Taiwan between May 5, 2016 and July 10, 2017. Eligible patients (aged 55–95 years) treated with the 10 cm²rivastigmine patch were enrolled based on physicians’ judgment and according to the Taiwan reimbursement criteria of the drug. Data were prospectively collected at Week 0 (baseline), Week 24, and Week 48. The primary endpoint was the change in the cognitive assessment screening instrument (CASI) scores at Week 48 versus baseline. The changes from baseline in clinical dementia rating (CDR), mini-mental state examination (MMSE), and neuropsychiatric inventory (NPI) scores were evaluated, as were treatment persistence and the safety profile.

Results

Of the 285 eligible patients [full analysis set (FAS)], 216 (75.8%) completed the study protocol while 180 (63.2%) persisted on the 10 cm² rivastigmine patch for the full 48 weeks. At baseline, 89.8% of patients had a CDR score of 0.5 or 1, while the change in CDR score at Week 48 was not significant. In the FAS, both the CASI and MMSE scores had numerical improvement at Week 24 but declined by 2.1 and 0.4 points, respectively, at Week 48 (p = 0.005 and p = 0.022). The increment in NPI scores was not significant. The most common drug-related adverse events (AEs) were pruritus (11.2%), nausea (3.5%), rash (3.2%), and vomiting (2.8%).

Conclusions

The use of the 10 cm² rivastigmine patch in the mild stage of AD maintained cognitive function at Week 24 and neuropsychiatric function at Week 48. The treatment persistency and safety profile support the clinical tolerability of the rivastigmine patch in the management of mild-to-moderate AD in Taiwan.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01893-6.

Evaluation of rivastigmine in Alzheimer's disease

Dementia is the major cause of mortality and morbidity in older adults, with Alzheimer's disease (AD) being the most common cause. AD has a significant impact on economic and psychosocial status. Cholinesterase inhibitors (ChEIs) are currently the mainstay in the management of AD. Rivastigmine is the only ChEI that inhibits both acetylcholinesterase and butyrylcholinesterase enzymes in the brain. This dual inhibition makes it potentially more effective for AD patients. Its availability as both a transdermal formulation and oral capsule, may improve adherence rates and care giver satisfaction compared with other ChEIs. To date, the data from randomized clinical trials and post marketing observational studies have shown evidence for an impact on cognitive functions in AD with good safety and tolerability.

Pharmacological Properties and Chemical Profiles of Passiflora foetida L. Extracts: Novel Insights for Pharmaceuticals and Nutraceuticals

In the present study, Passiflora foetida extracts characterized by different polarities were studied for their phytochemical profile, enzyme inhibitory, and antioxidant potentials. In silico, in vitro and ex vivo studies were also carried out on methanol and water extracts for predicting pharmacokinetics and pharmacodynamics. In this regard, neuronal HypoE22 cells, isolated mouse skin tissues, and pathogen dermatophytes strains were exposed to extracts. Emphasis was given to the preventing effects induced by the extracts on hydrogen peroxide-induced alterations of prostaglandin E2 (PGE2), l-dopa, and serotonin. Chemical analysis revealed the presence of similar compounds in infusion and methanolic extracts. The ex vivo studies also showed protective skin properties by P. foetida water and methanol extracts, as evidenced by the decrease of hydrogen peroxide-induced PGE2 level. Additionally, the blunting effects on hydrogen peroxide-induced l-dopa levels are consistent with the anti-tyrosinase effect exerted by both extracts. In silico studies demonstrated the affinity of extracts’ phytochemicals, namely apigenin, chrysoeriol, loliolide, luteolin, quercetin, and vitexin, towards cyclo-oxygenase-2 and tyrosinase. Finally, microbiological tests demonstrated the efficacy of P. foetida methanol and water extracts as anti-mycotic agents against Trichophyton and Arthroderma species, involved in skin inflammation. Hence, P. foetida L. extracts could represent potential sources of pharmaceuticals and nutraceuticals.

Strategies for Continued Successful Treatment in Patients with Alzheimer's Disease: An Overview of Switching Between Pharmacological Agents

Introduction:

Alzheimer’s disease (AD) is the most common cause of dementia, characterized by a progressive decline in cognition and function. Current treatment options for AD include the cholines-terase inhibitors (ChEIs) donepezil, galantamine, and rivastigmine, as well as the N-methyl-D-aspartate receptor antagonist memantine. Treatment guidelines recommend the use of ChEIs as the standard of care first-line therapy. Several randomized clinical studies have demonstrated the benefits of ChEIs on cogni-tion, global function, behavior and activities of daily living. However, patients may fail to achieve sus-tained clinical benefits from ChEIs due to lack/loss of efficacy and/or safety, tolerability issues, and poor adherence to the treatment. The purpose of this review is to explore the strategies for continued successful treatment in patients with AD.

Methods:

Literature search was performed for articles published in PubMed and MEDLINE, using pre-specified search terms. Articles were critically evaluated for inclusion based on their titles, abstracts, and full text of the publication.

Results and Conclusion:

The findings of this review indicate that dose up-titration and switching between ChEIs may help to improve response to ChEI treatment and also address issues such as lack/loss of effica-cy or safety/tolerability in patients with AD. However, well-designed studies are needed to provide robust evidence.

Efficacy, Safety, and Tolerability of Switching from Oral Cholinesterase Inhibitors to Rivastigmine Transdermal Patch with 1-Step Titration in Patients with Mild to Moderate Alzheimer's Disease: A 24-Week, Open-Label, Multicenter Study in Japan

Background

Few studies have investigated treatment options for patients with Alzheimer's disease (AD) showing a poor response to oral cholinesterase inhibitors (ChEIs) in Japan.

Objective

To investigate the efficacy and safety of switching from oral ChEIs to rivastigmine transdermal patch in patients with AD.

Methods

In this multicenter, open-label, phase IV study in outpatient clinics in Japan, patients with mild-moderate AD who had a poor response to or experienced difficulty in continuing donepezil or galantamine were switched to rivastigmine transdermal patch (5 cm²; loaded dose 9 mg, delivery rate 4.6 mg/24 h) with a 1-step titration in week 4 (10 cm²; loaded dose 18 mg, delivery rate 9.5 mg/24 h), which was continued for 4 weeks in the titration period and 16 weeks in a maintenance period. The primary endpoint was the change in Mini-Mental State Examination (MMSE) total score from baseline to week 24.

Results

A total of 118 patients were enrolled and switched to rivastigmine, of which 102 completed the 24-week study. The MMSE total score was essentially unchanged during the study, with a least-square mean change (SD) of −0.35 (2.64) at week 24 (p = 0.1750). Exploratory analysis with a mixed-effect model comparing changes in MMSE between the pre- and post-switch periods suggested that switching to rivastigmine prevented a worsening of MMSE. Application site skin reactions/irritations occurred in 30.5% of patients overall, in 22.0% in the 8-week titration period, and in 10.2% in the 16-week maintenance period.

Conclusion

Within-class switching from an oral ChEI to rivastigmine transdermal patch might be an efficacious and tolerable option for AD patients showing a poor or limited response to a prior oral ChEI.

Inhibition of β-site amyloid precursor protein cleaving enzyme 1 and cholinesterases by pterosins via a specific structure-activity relationship with a strong BBB permeability

We extracted 15 pterosin derivatives from Pteridium aquilinum that inhibited β-site amyloid precursor protein cleaving enzyme 1 (BACE1) and cholinesterases involved in the pathogenesis of Alzheimer's disease (AD). (2R)-Pterosin B inhibited BACE1, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with an IC₅₀ of 29.6, 16.2 and 48.1 µM, respectively. The K_i values and binding energies (kcal/mol) between pterosins and BACE1, AChE, and BChE corresponded to the respective IC₅₀ values. (2R)-Pterosin B was a noncompetitive inhibitor against human BACE1 and BChE as well as a mixed-type inhibitor against AChE, binding to the active sites of the corresponding enzymes. Molecular docking simulation of mixed-type and noncompetitive inhibitors for BACE1, AChE, and BChE indicated novel binding site-directed inhibition of the enzymes by pterosins and the structure-activity relationship. (2R)-Pterosin B exhibited a strong BBB permeability with an effective permeability (P_e) of 60.3×10^-6 cm/s on PAMPA-BBB. (2R)-Pterosin B and (2R,3 R)-pteroside C significantly decreased the secretion of Aβ peptides from neuroblastoma cells that overexpressed human β-amyloid precursor protein at 500 μM. Conclusively, our study suggested that several pterosins are potential scaffolds for multitarget-directed ligands (MTDLs) for AD therapeutics.

Compliance and persistence with Alzheimer's disease treatment: a retrospective analysis of multiregional hospital databases in Thailand

Aims: Due to the lack of studies evaluating compliance or persistence with Alzheimer's Disease (AD) treatment outside High-Income Countries (HICs), this study aimed to assess compliance, persistence, and factors associated with non-compliance and non-persistence by utilizing existing "real-world" information from multiregional hospital databases in Thailand.Materials and methods: Study subjects were retrospectively identified from databases of five hospitals located in different regions across Thailand. AD patients aged ≥60 years who were newly-prescribed with donepezil, galantamine, rivastigmine, or memantine between 2013 and 2017 were eligible for analysis. The Medication Possession Ratio (MPR) was used as a proxy for compliance, while the Kaplan-Meier survival analysis was employed to estimate persistence. Logistic and Cox regressions were used to assess determinants of non-compliance and non-persistence, adjusted for age and gender.Results: Among 698 eligible patients, mean (SD) MPR was 0.83 (0.25), with 70.3% of the patients compliant to the treatment (having MPR ≥ 0.80). Half of the patients discontinued their treatment (having a treatment gap >30 days) within 177 days with a 1-year persistence probability of 21.1%. The patients treated in the university-affiliated hospital were more likely to be both non-compliant (OR = 1.71; 95% CI = 1.21-2.42) and non-persistent (HR = 1.33; 95% CI = 1.12-1.58). In addition, non-compliance was higher for those prescribed with single AD treatment (OR = 2.52; 95% CI = 1.35-4.69), while non-persistence was higher for those unable to reimburse for AD treatment (HR = 1.34; 95% CI = 1.11-1.62).Limitations: By using retrospective databases, a difficulty in validating whether the medications are actually taken after being refilled may over-estimate the levels of compliance and persistence. Meanwhile, possible random coding errors may under-estimate the strength of association findings.Conclusions: This study reveals the situation of compliance and persistence on AD treatment for the first time outside HICs. The determinants of non-compliance and non-persistence underline key areas for improvement.

Clinical Management of Episodic Memory Changes in Dementia

PURPOSE OF REVIEW

The purpose of this review was to discuss therapeutic options available for the treatment of memory difficulties in dementia.

RECENT FINDINGS

Because of the lack of progress in the availability of new medications, there has been an increased interest in focusing on non-pharmacological means to management cognitive symptoms related to dementia. The clinical management of memory loss should focus both on pharmacological and non-pharmacological approaches. Treatment with medications should usually begin with a cholinesterase inhibitor and then followed by addition of memantine if there is a decline. In addition to medication management, emphasis should be placed on the importance of maintaining a healthy lifestyle that encompasses physical activities, cognitive stimulation, and a healthy diet.

Pharmacotherapy for Dementia: A Practical Approach to the Use of Cholinesterase Inhibitors and Memantine

Cholinesterase inhibitors and memantine are the only classes of drugs approved for the treatment of dementia due to Alzheimer's disease. This article provides evidence-based recommendations to address the issues regarding the use of cholinesterase inhibitors and memantine in clinical practice. It includes their efficacy, timing, assessment, use in institutionalized patients, combined use, and use in other dementia types. However, most of the studies are of short duration (<1 year) and are mainly focused on cognitive and global improvement, whereas the practical issue of their use in daily practice such as optimal duration of treatment, long-term efficacy and delaying institutionalization are limited.

Antioxidant activity, acetylcholinesterase inhibitory potential and phytochemical analysis of Sarcocephalus latifolius Sm. bark used in traditional medicine in Sudan

BACKGROUND

Sarcocephalus latifolius is used as a traditional medicine for curing many diseases in Sudan. The main objective of the current study was to determine the antioxidant activity and acetylcholinesterase inhibition (AChEI) of S. latifolius, and to estimate its total phenolic and flavonoid contents.

METHODS

Antioxidant activity of the tested plant extracts was carried out by determining their ability to scavenge the 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical. On the other hand, AChE inhibitory activity was determined spectrophotometrically using the Ellman's colorimetric method. The levels of total phenols and flavonoids were determined quantitatively using spectrophotometric methods. MTT assay was consumed to assess the cytotoxic effect of the most active fractions. These fractions were subjected to phytochemical analysis using GC-MS techniques to determine thier chemical composition.

RESULTS

Hexane and chloroform fractions exhibited the highest antioxidant activity with IC50 values of (0.098 ± 0.08 and 0.099 ± 0.029 mg/ml) respectively. Standard propyl gallate had the lowest IC50 value of 0.0414 ± 0.11 mg/ml. The ethanolic crude extract showed low AChEI activity with 40.2 ± 0.10%. High concentrations of phenolic and flavonoid contents were observed. GCMS revealed the presence of well-known antioxidants compounds e.g. Vitamin E and caffeic acid.

CONCLUSION

The ethanolic extract of bark of S. latifolius showed potent antioxidant effects and low AChEI activity, high phenolic and flavonoid contents and presence of pharmacologically active compounds. These findings explain its wide usages in traditional medicine.

Prunella vulgaris L., an Edible and Medicinal Plant, Attenuates Scopolamine-Induced Memory Impairment in Rats

Prunella vulgaris L. is as a major plant in the Chinese traditional functional beverage Guangdong herbal tea for the treatment of fevers, diarrhea, and sore mouth. In this study, ethyl acetate parts of aqueous extracts from P. vulgaris L. (EtOAc-APV) were found to demonstrate potent acetylcholinesterase (AChE) inhibition in vitro. Therefore, this study was designed to further investigate the effects of EtOAc-APV on scopolamine (SCOP)-induced aging rats. Male Wistar rats were randomly divided into four groups (n = 12) and given orally by gavage EtOAc-APV (100 mg/kg) for 3 weeks. SCOP (1 mg/kg, ip) was administered to rats 30 min before starting behavioral tests consecutively for 3 days. EtOAc-APV could attenuate SCOP-induced brain senescence in rats by improving behavioral performance and decreasing brain cell damage, which was associated with a notable reduction in AChE activity and MDA level, as well as an increase in SOD and GPx activities. Additionally, EtOAc-APV administration could reduce the expression of NF-κB and GFAP, which showed an anti-neuroinflammatory effect on the SCOP-treated rat. Overall, the current study highlights P. vulgaris L. as an antidementia dietary supplement.

Inhibitory activities of major anthraquinones and other constituents from Cassia obtusifolia against β-secretase and cholinesterases

ETHNOPHARMACOLOGICAL RELEVANCE

Semen Cassiae has been traditionally used as an herbal remedy for liver, eye, and acute inflammatory diseases. Recent pharmacological reports have indicated that Cassiae semen has neuroprotective effects, attributable to its anti-inflammatory actions, in ischemic stroke and Alzheimer's disease (AD) models.

AIM OF THE STUDY

The basic goal of this study was to evaluate the anti-AD activities of C. obtusifolia and its major constituents. Previously, the extract of C. obtusifolia seeds, was reported to have memory enhancing properties and anti-AD activity to ameliorate amyloid β-induced synaptic dysfunction. However, the responsible components of C. obtusifolia seeds in an AD are currently still unknown. In this study, we investigated the inhibitory effects of C. obtusifolia and its constituents against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) enzyme activity.

MATERIALS AND METHODS

In vitro cholinesterase enzyme assays by using AChE, BChE, and BACE1 were performed. We also scrutinized the potentials of Cassiae semen active component as BACE1 inhibitors via enzyme kinetics and molecular docking simulation.

RESULTS

In vitro enzyme assays demonstrated that C. obtusifolia and its major constituents have promising inhibitory potential against AChE, BChE, and BACE1. All Cassiae semen constituents exhibited potent inhibitory activities against AChE and BACE1 with IC50 values of 6.29-109µg/mL and 0.94-190µg/mL, whereas alaternin, questin, and toralactone gentiobioside exhibited significant inhibitory activities against BChE with IC50 values of 113.10-137.74µg/mL. Kinetic study revealed that alaternin noncompetitively inhibited, whereas cassiaside and emodin showed mixed-type inhibition against BACE1. Furthermore, molecular docking simulation results demonstrated that hydroxyl group of alaternin and emodin tightly interacted with the active site residues of BACE1 and their relevant binding energies (-6.62 and -6.89kcal/mol), indicating a higher affinity and tighter binding capacity of these compounds for the active site of BACE1.

CONCLUSION

The findings of the present study suggest the potential of C. obtusifolia and its major constituents for use in the development of therapeutic or preventive agents for AD, especially through inhibition of AChE, BChE and BACE1 activities.

Dementia and Comorbidities: An Overview of Diagnosis and Management

The term “dementia” describes various neurodegenerative disorders that effect cognition, including Alzheimer disease, vascular dementia, and others. This article reviews the diagnosis and management of common types of dementia and comorbidities. Dementias are differentiated clinically by history, symptom presentation, and exclusion of other causes through laboratory and imaging studies. Cholinesterase inhibitors are useful but may not be effective for all types of dementia and provide only modest benefits. Certain medical comorbidities may increase the risk of dementia, although genetics are also important in its etiology. Psychiatric comorbidities in dementia include delirium, which is treated primarily by addressing underlying medical disorders, but antipsychotics can be useful for symptom management and patient comfort. Nonpharmacologic interventions are first-line treatments for other psychiatric comorbidities, although drug therapy may be useful in some cases. The management of patients with dementia presents many challenges and will continue to do so unless agents with pronounced disease-modifying capabilities are developed.

Efficacy of Galantamine on Cognition in Mild-to-Moderate Alzheimer's Dementia after Failure to Respond to Donepezil

OBJECTIVE

This study compares the efficacy of the cholinesterase inhibitor (ChEI) galantamine on cognition in patients with mild-to-moderate Alzheimer's dementia (AD) who were either naïve to ChEI drugs or who had failed a trial of the ChEI donepezil.

METHODS

Outpatients with AD were sequentially referred for screening and enrollment. Current outpatients who had taken donepezil for at least 6 months without demonstrated efficacy on cognition were switched to galantamine (switched group). New outpatients with no ChEI prescription history were classified as the naïve group and were given galantamine. The primary outcome measures for the between-group comparison were response rate on cognition at 26 and 52 weeks (categorical) and change on the Korean version of the Alzheimer's Disease Assessment Scale-cognitive subscale (dimensional). Secondary cognitive outcomes were measured using the subset of frontal executive function and the Korean Mini-Mental State Examination.

RESULTS

Seventy outpatients were enrolled and 66 were analyzed by Intent-to-treat (ITT). There were 42 cases in the naïve group and 24 in the switched group. Response rates did not differ at 26 weeks (71.4% naïve vs. 58.3% switched; p=0.277) or at 52 weeks (59.5% naïve vs. 41.6% switched; p=0.162). No significant differences were observed in the pattern of change over the 52 weeks on the primary and secondary cognitive scales.

CONCLUSION

As the efficacy of galantamine on cognition was not inferior in the switched group compared to that in the naïve group, switching ChEI drugs is clinically feasible for non-responding patients with mild-to-moderate AD.

The Use of Cholinesterase Inhibitors Across All Stages of Alzheimer's Disease

Current pharmacological therapy for Alzheimer's disease (AD) includes the cholinesterase inhibitors (ChEIs) donepezil, rivastigmine, and galantamine and the N-methyl D-aspartate receptor antagonist memantine. Based on the results of randomized controlled trials and several meta-analyses, ChEIs appear to show modest but statistically significant improvements on several measures, including cognition and global functioning. Given their modest effects, there is a lack of consensus among clinicians regarding issues related to initiation, optimal duration, and discontinuation of ChEI therapy across the spectrum of AD. There is evidence from long-term observational controlled studies that early initiation and persistent exposure to AD therapy lead to delays in nursing home admission and significantly slower rates of cognitive and functional impairment. In the moderate to severe stages of AD, therapeutic trials of higher dose ChEIs and the addition of memantine are recommended for patients who are no longer responding to lower doses. While side effects are generally mild and gastrointestinal in nature, these events can lead to significant morbidity in more susceptible patients with advanced disease. Patients should thus be regularly monitored for any potential serious side effects of ChEI therapy, which also may include syncope and bradycardia. At the terminal stages of AD, such as when patients become hospice eligible, attempts to cautiously discontinue all medications not necessary for quality of life, including AD drugs, should be made.

Brain metabolism and Alzheimer's disease: the prospect of a metabolite-based therapy

The brain is one of the most energy-demanding organs in the body. It has evolved intricate metabolic networks to fulfill this need and utilizes a variety of substrates to generate ATP, the universal energy currency. Any disruption in the supply of energy results in various abnormalities including Alzheimer's disease (AD), a condition with markedly diminished cognitive ability. Astrocytes are an important participant in maintaining the cerebral ATP budget. However, under oxidative stress induced by numerous factors including aluminum toxicity, the ability of astroctyes to generate ATP is impaired due to dysfunctional mitochondria. This leads to globular, glycolytic, lipogenic and ATP-deficient astrocytes, cerebral characteristics common in AD patients. The reversal of these perturbations by such natural metabolites as pyruvate, α-ketoglutarate, acetoacetate and L-carnitine provides valuable therapeutic cues against AD.

[Guidelines on "pharmacotherapy of neurodegenerative dementia": an update]

This article presents the evidence-based pharmacotherapeutic options for the most common forms of neurodegenerative dementia. The aim is to present the recommendations derived from the relevant studies on the neurological, psychiatric and geriatric practice of treatment for dementia patients. The text is derived from the 2009 guidelines of the German Society of Neurology (DGN, lead management: K. Fassbinder), the S3 guidelines of the DGN/German Association for Psychiatry, Psychotherapy and Psychosomatics (DGPPN, lead management: G. Deuschl and W. Maier) and the latest amendments of the European Federation of Neurological Societies/European Society of Neurology (EFNS-ENS, Sorbi et al. Eur J Neurol 19:1159-1179, 2012) guidelines. The forms of neurodegenerative dementia addressed are Alzheimer's disease, frontotemporal dementia and Lewy body dementia. Specific statements on the treatment of dementia in Parkinson's disease and vascular dementia can be found in separate guidelines. An analogous article on psychosocial interventions was recently published in Der Nervenarzt (Kurz, Nervenarzt 84:93-103, 2013).

Effectiveness of switching to the rivastigmine transdermal patch from oral cholinesterase inhibitors: a naturalistic prospective study in Alzheimer's disease

Oral donepezil and rivastigmine are two commonly used cholinesterase inhibitors (ChEIs) used in Alzheimer's disease (AD). The rivastigmine transdermal patch formulation has high tolerability profile, allowing patients to achieve optimal therapeutic doses and providing potential advantages over oral ChEIs. This is a 6-month, multicentre, observational efficacy and tolerability study of switching from oral ChEIs to rivastigmine patch in AD patients who failed to show benefit from previous treatment. The reasons of the switch were: (1) lack/loss of benefit from previous oral ChEI treatment; (2) tolerability problems. The primary outcome was cognitive changes measured with the mini-mental state examination (MMSE) test. Secondary outcomes were modifications of functional independence and behavioral disturbances and occurrence of adverse events (AEs) after switching. 174 patients, over 180 patients screened, entered the study (lack/loss of efficacy: 57 %, tolerability problems: 33 %, both reasons: 10 %). 6 months after switching 56 % of patients stabilized or increased the MMSE score respect to baseline. The only predictor of this outcome was the response at 3 months. In the group with lack/loss of response to oral ChEI, the decline of the MMSE score changed from -3.4 ± 2.5 points in the 6 months before switching to -0.5 ± 3.2 in the 6 months after the switch (p < 0.001). There were no significant changes in the IADL or NPI scores. Drug discontinuation rate was 20 %, due to AEs (18 %) and lack of compliance (2 %). Switching from an unsuccessful oral ChEI therapy to rivastigmine patch is effective and safe in more than half of the switched patients after a 6-month period.

Drug persistency of cholinesterase inhibitors for patients with dementia of Alzheimer type in Korea

This study examined 1-year persistency with cholinesterase inhibitors (ChEIs) for the treatment of elderly Alzheimer's dementia (AD) patients in Korea. Korean Health Insurance Review & Assessment Service database from January 2005 to June 2006 was used. Patients aged 65 or older with AD diagnosis who were first prescribed a ChEI were included. The 1-year persistence, persistency rate, and switching patterns during the follow-up period were identified. Mean time to drug discontinuation was analyzed, and persistency rates between different patient factors were compared. The 1-year persistency rate of newly treated 6,461 AD patients was 24.0%, while 50% of study patients discontinued treatment by 91 days from initiation. Persistency rates of female patients (22.8%), patients in rural areas (12.7%), and primary care (10.2%) were relatively low (p < 0.001). Persistency rate differed between age groups (p < 0.001). Overall proportion of switching was 6.6%. The 1-year persistency rate of ChEIs for AD patients in Korea did not reach those of previous researches in other countries. Patients less likely to remain on therapy should be especially monitored to optimize treatment persistence.

Patient adherence to transdermal rivastigmine after switching from oral donepezil: a retrospective claims database study

OBJECTIVE

To examine patient adherence before and after switching from donepezil to the rivastigmine patch.

METHODS

This retrospective cohort study used the MarketScan Commercial and Medicare data sets (2004 to 2009). Patients with a diagnosis of Alzheimer disease who were new donepezil users and were subsequently switched to the rivastigmine patch were included. The proportion of days covered (PDC) and PDC difference between donepezil and the rivastigmine patch were calculated from the time of initiation to the switch, capped at 1 year after the first respective claim. PDC was calculated as the number of days with drugs available divided by the number of days in the respective follow-up periods.

RESULTS

The sample included 772 patients (mean age 77 y; 58% female). The mean time between switching from donepezil to the rivastigmine patch was 579 (SD=317.3) days. The mean PDC for the rivastigmine patch was highest among patients who switched within 3 months (80.4% vs. 90.7%; P=0.04) and within 7 to 9 months (61.3% vs. 71.0%; P=0.05) of initiating donepezil. When adherence was analyzed in increments of 1 year, patients who switched to the rivastigmine patch within the first year of treatment had significantly greater adherence to rivastigmine compared with those who were on donepezil (PDC 69.3% vs. 60.6%; P=0.0004).

CONCLUSIONS

Switching from donepezil to the rivastigmine patch seems to be associated with increased adherence, especially in patients who switched within the first year of initiating donepezil.

In-vitro evaluation of selected Egyptian traditional herbal medicines for treatment of Alzheimer disease

BACKGROUND

Egyptians recognized the healing power of herbs and used them in their medicinal formulations. Nowadays, "Attarin" drug shops and the public use mainly the Unani medicinal system for treatment of their health problems including improvement of memory and old age related diseases. Numerous medicinal plants have been described in old literature of Arabic traditional medicine for treatment of Alzheimer's disease (AD) (or to strengthen memory).

METHODS

In this study, some of these plants were evaluated against three different preliminary bioassays related to AD to explore the possible way of their bio-interaction. Twenty three selected plants were extracted with methanol and screened in vitro against acetylcholinesterase (AChE) and cycloxygenase-1 (COX-1) enzymes. In addition, anti-oxidant activity using DPPH was determined.

RESULTS

Of the tested plant extracts; Adhatoda vasica and Peganum harmala showed inhibitory effect on AChE at IC50 294 μg/ml and 68 μg/ml respectively. Moreover, A. vasica interacted reversibly with the enzyme while P. harmala showed irreversible inhibition. Ferula assafoetida (IC50 3.2 μg/ml), Syzygium aromaticum (34.9 μg/ml) and Zingiber officinalis (33.6 μg/ml) showed activity against COX-1 enzyme. Potent radical scavenging activity was demonstrated by three plant extracts Terminalia chebula (EC50 2.2 μg/ml), T. arjuna (3.1 μg/ml) and Emblica officinalis (6.3 μg/ml).

CONCLUSION

Interestingly, differential results have been obtained which indicate the variability of the mode of actions for the selected plants. Additionally, the reversible interaction of A. vasica against AChE and the potent activity of F. assafoetida against COX-1 make them effective, new and promising agents for treatment of AD in the future, either as total extracts or their single bioactive constituents.

Persistence of cholinesterase inhibitor treatment in dementia: insights from a naturalistic study

BACKGROUND

Cholinesterase inhibitors (ChEI) are widely used in dementia, but there is a lack of practice guidelines in case of intolerance or absence of perceived effect.

METHODS

Two hundred and forty patients (mean age 77 years, SD 6.3, 66% female) with Alzheimer's disease or Lewy body dementia were prescribed a ChEI and evaluated annually under conditions of standard practice. Of these, 152 patients maintained, 36 switched, and 52 abandoned ChEI treatment.

RESULTS

Less behavioural disturbance and less cognitive deterioration were observed, respectively, at the 3- and 4-year follow-up assessments in the patients who maintained the first prescribed ChEI (p < 0.05). Cognitive benefits were reinforced in the patients who experienced some adverse event, but no benefits were observed when the patient or caregiver did not perceive an effect.

CONCLUSIONS

Maintenance of the first prescribed ChEI was supported when some benefit was perceived by the patient or caregiver, even in cases of nonserious adverse events.

Clinically meaningful treatment responses after switching to galantamine and with addition of memantine in patients with Alzheimer's disease receiving donepezil

Clinical trials have shown the benefits of acetylcholinesterase inhibitors, such as donepezil and galantamine, and an N-methyl-D-aspartate receptor antagonist, memantine, in patients with Alzheimer's disease (AD). However, little is known regarding the effects of switching from donepezil 5 mg/day to galantamine 16 or 24 mg/day, or regarding the effects of adding memantine to established therapy compared with increasing the dose of donepezil. This report discusses two studies conducted to evaluate treatment with galantamine and memantine with respect to cognitive benefits and caregiver evaluations in patients with AD receiving donepezil 5 mg/day for more than 6 months. Patients with mild or moderate AD (scores 10-22 on the Mini-Mental State Examination) were enrolled in the Galantamine Switch study and switched to galantamine (maximum doses 16 mg versus 24 mg). Patients with moderate to severe AD (Mini-Mental State Examination scores 3-14) were enrolled in the Donepezil Increase versus Additional Memantine study and either had their donepezil dose increased to 10 mg/day or memantine 20 mg/day added to their existing donepezil dose. Patients received the study treatment for 28 weeks and their Disability Assessment for Dementia, Mental Function Impairment Scale, Cohen-Mansfield Agitation Inventory, and Neuropsychiatric Inventory scores were assessed with assistance from their caregivers. For the Galantamine Switch study after 8 weeks, agitation evaluated by the Cohen-Mansfield Agitation Inventory improved in both the 16 mg and 24 mg groups compared with baseline. However, there were no significant differences between the two galantamine groups. Agitation was also less in patients in the additional memantine group than in the donepezil increase group. In summary, switching to galantamine from donepezil and addition of memantine in patients with AD receiving donepezil were both safe and meaningful treatment options, and particularly efficacious for suppression of agitation.

Simulations of symptomatic treatments for Alzheimer's disease: computational analysis of pathology and mechanisms of drug action

Introduction

A substantial number of therapeutic drugs for Alzheimer's disease (AD) have failed in late-stage trials, highlighting the translational disconnect with pathology-based animal models.

Methods

To bridge the gap between preclinical animal models and clinical outcomes, we implemented a conductance-based computational model of cortical circuitry to simulate working memory as a measure for cognitive function. The model was initially calibrated using preclinical data on receptor pharmacology of catecholamine and cholinergic neurotransmitters. The pathology of AD was subsequently implemented as synaptic and neuronal loss and a decrease in cholinergic tone. The model was further calibrated with clinical Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog) results on acetylcholinesterase inhibitors and 5-HT6 antagonists to improve the model's prediction of clinical outcomes.

Results

As an independent validation, we reproduced clinical data for apolipoprotein E (APOE) genotypes showing that the ApoE4 genotype reduces the network performance much more in mild cognitive impairment conditions than at later stages of AD pathology. We then demonstrated the differential effect of memantine, an N-Methyl-D-aspartic acid (NMDA) subunit selective weak inhibitor, in early and late AD pathology, and show that inhibition of the NMDA receptor NR2C/NR2D subunits located on inhibitory interneurons compensates for the greater excitatory decline observed with pathology.

Conclusions

This quantitative systems pharmacology approach is shown to be complementary to traditional animal models, with the potential to assess potential off-target effects, the consequences of pharmacologically active human metabolites, the effect of comedications, and the impact of a small number of well described genotypes.

Acetylcholine and memory-enhancing activity of Ficus racemosa bark

Background:

Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in dementia and enhancement of acetylcholine (Ach) levels in brain using acetylcholinesterase inhibitors is one of the most important approaches for the treatment of AD.

Methods:

In this study, aqueous extract of Ficus racemosa Linn. (Moraceae) bark having anti-inflammatory, antioxidant, and anticholinesterase activity was evaluated for its ability to enhance Ach levels, and to ascertain its antidementia activity in rats. This work was carried out under the assumption that the F. racemosa extract may show combination of actions which could be beneficial in the treatment of AD, such as neuroprotection, attributed to antioxidant and anti-infl ammatory property and may elevate levels of Ach like Ficus hispida extract reported earlier.

Results:

Administration of the extract at two levels viz., 250 and 500 mg/kg signifi cantly raised (P ≤ 0.05) Ach levels in hippocampi of rats compared to control. The percentage enhancement in Ach levels was found to be 22% and 38%, respectively. Further, the extract at both dosage levels elicited signifi cant reduction (P ≤ 0.05) in transfer latency on elevated plus-maze, which was used as an exteroceptive behavioral model to evaluate memory in rats.

Conclusion:

It is inferred that it would be worthwhile to explore the potential of F. racemosa in the management of Alzheimer disease.

Safety and efficacy of rivastigmine in patients with Alzheimer's disease not responding adequately to donepezil: an open-label study

OBJECTIVE

Switching patients with Alzheimer's disease from one cholinesterase inhibitor to another represents a viable option for patients not responding to current therapy. The objective of this large U.S.-based study was to evaluate the safety and efficacy of a treatment switch to rivastigmine in patients not responding adequately to or declining on treatment with donepezil.

METHOD

In this 26-week, prospective, open-label, single-arm, multicenter study conducted from April 24, 2003, to June 25, 2004, patients with mild-to-moderate Alzheimer's disease (DSM-IV-TR criteria) who were not responding to donepezil were treated with rivastigmine 3-12 mg/day. Safety and tolerability were measured by the occurrence of adverse events and patient disposition. Treatment effects on global functioning were assessed using the Clinical Global Impression of Change (CGIC) scale.

RESULTS

Two hundred seventy patients with a mean age of 78.5 (SD = 7.56) years and a mean duration of dementia of 3.5 (SD = 2.06) years were included in the study. Sixty-nine percent of patients completed the study with 17.8% discontinuing due to adverse events. Eighty-three percent of patients reported at least 1 adverse event, with the most frequently occurring adverse events affecting the gastrointestinal system (54%). The majority of patients were reported to have either improvement or no decline on the CGIC. A limitation of the study is that the interpretation of the results is based on an overall completion rate of 69%.

CONCLUSION

Immediately switching patients from donepezil to rivastigmine without a washout period was safe and well tolerated in the current study. Additionally, these results suggest that patients not responding adequately to or declining while taking donepezil may improve or stabilize after switching to rivastigmine.

Two galantamine titration regimens in patients switched from donepezil

OBJECTIVES

In addition to inhibiting acetylcholinesterase, galantamine has allosteric-modulating activity at nicotinic receptors. This may make galantamine an attractive option for patients starting treatment for Alzheimer's disease (AD), but also for those who have not benefited from their current therapy. This study explored outcomes in subjects with AD transitioning from donepezil because of insufficient tolerability or efficacy.

MATERIALS AND METHODS

Subjects previously receiving donepezil for mild-to-moderate AD were enrolled in a 12-week randomized, open-label study. After screening and a 7-day washout, subjects were randomly allocated to galantamine fast (8 mg/week increments) or slow (8 mg/4 week) titration to 16-24 mg. Efficacy outcomes included the Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-cog/11), Mini-Mental State Examination (MMSE), Clinician's Interview-Based Impression of Change - Plus Caregiver's Input (CIBIC-plus) and Alzheimer's Disease Cooperative Study - Activities of Daily Living Inventory (ADCS-ADL).

RESULTS

Eighty-six of 89 patients (fast titration, n = 44; slow titration, n = 45) completed the study. At week 12, ADAS-cog/11 score improved from screening by 2.6 and 0.6 in the fast- and slow-titration arms, respectively (overall, -1.6; P = 0.002). MMSE scores improved slightly in both arms (overall, +0.9; P = 0.002). Two-thirds of patients had improvement or no change on the CIBIC-plus at week 12. ADCS-ADL scores did not change significantly from screening in either treatment arm. Galantamine was generally well tolerated; nausea (5.6%) and bradycardia (4.5%) were the most commonly reported adverse events.

CONCLUSIONS

Patients in whom donepezil is ineffective or poorly tolerated may benefit from a switch to galantamine.

Effectiveness and tolerability of transdermal rivastigmine in the treatment of Alzheimer's disease in daily practice

BACKGROUND

Oral cholinesterase inhibitors at doses efficacious for the treatment of Alzheimer's disease (AD) are often prematurely discontinued due to gastrointestinal side effects. In controlled clinical trials, transdermal rivastigmine demonstrated less such effects at similar efficacy. The current study aimed to verify the validity of this data in daily practice.

METHODS

This was a prospective, multicenter, observational study on transdermal rivastigmine in Germany. Eligible patients were those with AD who had not yet been treated with rivastigmine. Outcome measures were changes in clock-drawing test, Mini-Mental State Examination (MMSE), Caregiver Burden Scale, Clinical Global Impression (CGI), physicians' assessments of tolerability, and the incidence of adverse events (AEs) over 4 months of treatment.

RESULTS

In 257 centers 1113 patients were enrolled; 614 women and 499 men, mean age 76.5 years. In 58% of patients AD was treated for the first time and in 42% therapy was switched to transdermal rivastigmine, mostly due to lack of tolerability (13.6%) or effectiveness (26.9%). After 4 months, 67.4% of patients were on the target dose of 9.5 mg/day and 21.8% were still on 4.6 mg/day. MMSE significantly improved in patients with and without pretreatment (ΔMMSE, 0.9 ± 3.4 and 0.8 ± 3.4, respectively, both P < 0.001); the CGI score improved in 60.9% and 61.3% of patients, respectively. Overall 11.7% of patients had AEs, mainly affecting the skin or the gastrointestinal tract; in 1.1% of cases AEs were serious; 14.7% of patients discontinued therapy, 6.0% due to AEs. With rivastigmine treatment the percentage of patients taking psychotropic comedication decreased, particularly in first-time treated rivastigmine patients (from 27.1% to 22.6%; P < 0.001).

CONCLUSION

Results were in line with data from controlled clinical trials. Switching from any other oral acetylcholinesterase inhibitor to transdermal rivastigmine may improve cognition.

Efficacy and safety of switching from oral cholinesterase inhibitors to the rivastigmine transdermal patch in patients with probable Alzheimer's disease

Background and Purpose

The goal of this study was to estimate the efficacy and safety of the rivastigmine transdermal patch in patients with probable Alzheimer's disease (AD) who cannot tolerate or do not respond to oral cholinesterase inhibitors (ChEIs).

Methods

A 24-week, prospective, open-label, single-arm, multicenter study was conducted from June 2009 to June 2010 in patients with probable AD. The enrolled patients had either a poor response or a decline in global function after treatment with oral ChEIs, or they were not able to tolerate treatment with oral ChEIs due to adverse events such as nausea or vomiting. A poor response was defined as a decrease of at least 2 points on the Korean version of the Mini-Mental State Examination (K-MMSE) within the previous 6 months (the decline in global function was determined by the investigator or caregiver). The efficacy of treatment was assessed using a follow-up Clinical Global Impression of Change (CGIC) assessment and K-MMSE conducted after 24 weeks, and safety was measured by the occurrence of adverse events and patient disposition.

Results

In total, 164 patients aged 74.7±7.52 years (mean±SD) and with 5.12±3.64 years of education were included. The study was completed by 70% of the patients (n=116), with 12.2% discontinuing due to adverse events. The most frequently reported adverse events (11%) were skin lesions, such as erythema or itching, followed by gastrointestinal problems (1.2%). Either an improvement or no decline in CGIC scores was reported for 82% of the patients.

Conclusions

The immediate switching of patients from an oral ChEI to the rivastigmine transdermal patch without a washout period was safe and well tolerated by the probable-AD patients in this study.

Switching from oral donepezil to rivastigmine transdermal patch in Alzheimer's disease: 20-week extension phase results

OBJECTIVE

To evaluate the long-term safety, tolerability, and efficacy of 2 strategies for switching from donepezil to rivastigmine transdermal patches in patients with mild to moderate Alzheimer's disease.

METHOD

This was a prospective, 25-week, randomized, open-label, parallel-group study to evaluate an immediate or delayed switch (7-day withdrawal) from donepezil (5 to 10 mg/d) to rivastigmine transdermal patches (4.6 mg/24 h). Participants included male and female patients, aged ≥ 50 years, with a DSM-IV-TR diagnosis of mild to moderate dementia of the Alzheimer's type, defined as a Mini-Mental State Examination score of 10-24, inclusive. Patients were enrolled between February 2007 and February 2008. The study was split into a 5-week core phase and a 20-week extension phase. Safety and efficacy results from the extension phase are presented.

RESULTS

Both switching strategies were well tolerated. Rates of discontinuation for any reason were similar between the groups. Discontinuations due to adverse events were also similar, and the incidence of gastrointestinal adverse events was low. Apart from Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale scores, at the end of the study, there was no statistically significant change from baseline in cognitive, behavioral, or global outcomes. Over half of the patients preferred rivastigmine transdermal patches to a tablet.

CONCLUSIONS

This study suggests that the majority of patients receiving donepezil tablets can be safely switched to rivastigmine transdermal patches without significant deterioration in cognition, behavior, and global functioning.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00305903.

Turning principles into practice in Alzheimer's disease

The prevalence of dementia is reaching epidemic proportions globally, but there remain a number of issues that prevent people with dementia, their families and caregivers, from taking control of their condition. In 2008, Alzheimer's Disease International (ADI) launched a Global Alzheimer's Disease Charter, which comprises six principles that underscore the urgency for a more ambitious approach to diagnosis, treatment and care. This review highlights some of the most important aspects and challenges of dementia diagnosis and treatment. These issues are reviewed in light of the six principles of the recent ADI Charter: promoting dementia awareness and understanding; respecting human rights; recognizing the key role of families and caregivers; providing access to health and social care; stressing the importance of optimal diagnosis and treatment; and preventing dementia through improvements in public health. The authors continue to hope that, one day, a cure for Alzheimer's disease will be found. Meanwhile, healthcare professionals need to unite in rising to the challenge of managing all cases of dementia, using the tools available to us now to work toward improved patient care.

Switching from oral cholinesterase inhibitors to the rivastigmine transdermal patch

Oral cholinesterase inhibitors (ChEIs) are associated with side effects such as nausea and vomiting. The use of transdermal patches for ChEI delivery may help to minimize these problems. The objective of this review was to consider available data from patients switching from oral ChEIs to transdermal rivastigmine treatment, and to suggest practical guidelines for patients wishing to do this. Literature database and reference list searches were performed to identify suitable publications. Data from two clinical trials and a series of open observational studies, in which patients were switched to the rivastigmine patch from oral rivastigmine, donepezil tablets, or galantamine, were evaluated. Adverse events were tabulated. In the studies reported here, nausea was reported in up to 3.2% and vomiting in up to 1.9% of patients switching to the rivastigmine patch from oral rivastigmine. Similar rates (up to 3.8% of patients for nausea and 0.8% of patients for vomiting) were reported when switching to the rivastigmine patch from donepezil tablets, and no nausea or vomiting was reported in a case study of patients switching to the rivastigmine patch from galantamine tablets. Switching regimes used in clinical trials appeared well tolerated. Data support recommendations for patients on high rivastigmine capsule doses to switch directly to the 9.5 mg/24 h rivastigmine patch, while those on lower oral rivastigmine doses should start on the 4.6 mg/24 h patch for 4 weeks before increasing to the 9.5 mg/24 h patch. This latter regimen is recommended for patients on other oral cholinesterase inhibitors if switching is medically indicated or requested by the patient or the caregiver.

Switching from donepezil tablets to rivastigmine transdermal patch in Alzheimer's disease

OBJECTIVE

Evaluate safety and tolerability of switching from donepezil to rivastigmine transdermal patch in patients with mild to moderate Alzheimer's disease.

METHODS

Prospective, parallel-group, open-label study to evaluate immediate or delayed switch from 5-10 mg/day donepezil to 4.6 mg/24 h rivastigmine following a 4-week treatment period.

RESULTS

Rates of discontinuation due to any reason or adverse events were similar between groups. Incidences of gastrointestinal adverse events were 3.8% in the immediate and 0.8% in the delayed switch group. No patients discontinued secondary to nausea and vomiting. Discontinuations due to application site reactions were low (2.3%). Asymptomatic bradycardia was more common following the immediate switch (2.3% vs 0%); however, these patients had coexisting cardiac comorbidities.

CONCLUSION

Both switch strategies were safe and well tolerated. The majority of patients may be able to switch directly to rivastigmine patches without a withdrawal period. Appropriate clinical judgment should be used for patients with existing bradycardia or receiving beta blockers.

A 50-year-old man with deteriorating cognitive function and impaired movement

Andrew Larner discusses the diagnosis and management of a man referred to the Cognitive Function Clinic with a 12- to 18-month history of deteriorating memory.

Treatment options in Alzheimer's disease: maximizing benefit, managing expectations

Alzheimer's disease (AD) is becoming an increasingly heavy burden on the society of developed countries, and physicians now face the challenge of providing efficient treatment regimens to an ever-higher number of individuals affected by the disease. Currently approved anti-AD therapies - the cholinesterase inhibitors and the N-methyl-D-aspartate receptor antagonist memantine - offer modest symptomatic relief, which can be enhanced using combination therapy with both classes of drugs. Additionally, alternative therapies such as nonsteroidal anti-inflammatory drugs, vitamin E, selegiline, Ginkgo biloba extracts, estrogens, and statins, as well as behavioral and lifestyle changes, have been explored as therapeutic options. Until a therapy is developed that can prevent or reverse the disease, the optimal goal for effective AD management is to develop a treatment regimen that will yield maximum benefits for individual patients across multiple domains, including cognition, daily functioning, and behavior, and to provide realistic expectations for patients and caregivers throughout the course of the disease. This review provides a basic overview of approved AD therapies, discusses some pharmacologic and nonpharmacologic treatment strategies that are currently being investigated, and offers suggestions for optimizing treatment to fit the needs of individual patients.

Is long-term treatment of Alzheimer's disease with cholinesterase inhibitor therapy justified?

The cholinesterase inhibitors (ChEIs) donepezil, rivastigmine and galantamine are the current mainstays in the drug treatment of Alzheimer's disease (AD). There is convincing evidence that these agents provide at least modest cognitive, behavioural and functional benefit for 6-12 months at all stages of the disease. Longer term benefits cannot be directly examined by placebo-controlled trials. Nevertheless, the results of virtually all open-label extensions of the pivotal trials, studies of patients with AD at different levels of severity and clinical trials using other designs favour treatment over no treatment for periods of up to 5 years. There are plausible biological reasons why ChEIs might be expected to work over a prolonged period of time although, to date, studies using various markers to chart the effects of medication on long-term disease progression have yielded mixed results. The most contentious issue regarding long-term treatment is economic, but the majority of available economic analyses suggest net savings over the long term if patients with AD receive persistent treatment with ChEIs.

Effective pharmacologic management of Alzheimer's disease

In order to assist physicians in the effective pharmacologic management of this challenging population, evidence-based pharmacologic treatment algorithms for the different stages of Alzheimer's disease have been developed. Evidence-based guidelines outlining pharmacotherapeutic strategies can be systematically implemented to optimize outcomes for patients in different stages of Alzheimer's disease. The first step toward the best possible long-term management is early diagnosis of Alzheimer's disease, thereby facilitating early initiation of cholinesterase inhibitor treatment, which may stabilize/reduce the rate of symptomatic cognitive and functional decline. Cholinesterase inhibitor therapy with rivastigmine, donepezil, or galantamine is endorsed as standard first-line therapy in patients with mild-to-moderate Alzheimer's disease. The N-methyl-D-aspartate receptor-antagonist, memantine, may be used as monotherapy or in combination with a cholinesterase inhibitor for patients with moderate Alzheimer's disease, and as monotherapy for patients with severe Alzheimer's disease. During treatment, cognitive and functional status should be monitored over 6-month intervals, and pharmacologic therapy should ideally be continued until there are no meaningful social interactions and quality of life has irreversibly deteriorated.

Excessive hippocampal acetylcholine levels in acetylcholinesterase-deficient mice are moderated by butyrylcholinesterase activity

Central cholinergic systems are involved in a plethora of brain functions and are severely and selectively damaged in neurodegenerative diseases such as Alzheimer's disease and dementia with Lewy bodies. Cholinergic dysfunction is treated with inhibitors of acetylcholinesterase (AChE) while the role of butyrylcholinesterase (BChE) for brain cholinergic function is unclear. We have used in vivo microdialysis to investigate the regulation of hippocampal acetylcholine (ACh) levels in mice that are devoid of AChE (AChE-/- mice). Extracellular ACh levels in the hippocampus were 60-fold elevated in AChE-/- mice compared with wild-type (AChE+/+) animals. In AChE-/- mice, calcium-free conditions reduced hippocampal ACh levels by 50%, and infusion of tetrodotoxin by more than 90%, indicating continuous ACh release. Infusion of a selective AChE inhibitor (BW284c51) caused a dose-dependent, up to 16-fold increase of extracellular ACh levels in AChE+/+ mice but did not change ACh levels in AChE-/- mice. In contrast, infusion of a selective inhibitor of BChE (bambuterol) caused up to fivefold elevation of ACh levels in AChE-/- mice, but was without effect in AChE+/+ animals. These results were corroborated with two other specific inhibitors of AChE and BChE, tolserine and bis-norcymserine, respectively. We conclude that lack of AChE causes dramatically increased levels of extracellular ACh in the brain. Importantly, in the absence of AChE, the levels of extracellular ACh in the brain are controlled by the activity of BChE. These results point to a potential usefulness of BChE inhibitors in the treatment of central cholinergic dysfunction in which brain AChE activity is typically reduced.