Memantine treatment in patients with moderate to severe Alzheimer disease already receiving donepezil: a randomized controlled trial

A brief review of the pharmacologic and therapeutic aspects of memantine in Alzheimer's disease

The past decade has seen an increase in therapeutic options for Alzheimer's disease (AD) that target neurotransmitters, such as acetylcholine, and research continues to target abnormal proteins in the AD brain. Recently, glutamate excitotoxicity has also become a target for AD treatment with the advent of memantine. Clinical trial data reviewed for memantine show good tolerability, low side-effect profiles and a positive therapeutic impact in moderate-to-severe AD, both as monotherapy and in conjunction with donepezil. However, additional data suggest variable benefits in the mild stages of AD. Furthermore, published reports support reduced dosing in patients with significant renal disease. However, the opportunity to target a second mechanism in the treatment of AD, thereby providing added symptomatic benefit, appears to be a useful consideration for clinicians who treat this devastating neurodegenerative disorder.

Target symptoms and outcome measures: cognition

The Cognitive section of the Alzheimer's Disease Assessment Scale (ADAS-Cog) remains the most widely used cognitive measure in dementia trials although it does not assess attention, executive function, or agnosia. Designed for use in Alzheimer's disease (AD), it may not be ideal in assessing patients with other diagnoses. The ADAS-Cog differentiates between AD patients, patients with Mild Cognitive Impairment, and normal controls. It has been used in trials of drugs for vascular and mixed dementia and dementia with Lewy bodies. It is not clear that the ADAS-Cog is adequate for assessing cognition in frontotemporal dementia. Well-validated aphasia batteries, such as the Western Aphasia Battery, can be used to assess language. Brief tests of frontal function such as the Frontal Assessment Battery or the Executive Interview might be useful additions in frontotemporal dementia trials. The most widely used assessment tool for patients with advanced dementia is the Severe Impairment Battery. The domains tested are analogous to those assessed by the ADAS-Cog. The Mini-Mental State Exam and the Modified Mini-Mental State Examination are useful in stratifying patients for trial entry. Cognitive measures better tailored to the diseases in question are needed for non-Alzheimer dementias.

Global measures: utility in defining and measuring treatment response in dementia

Global measures used in treatment trials in dementia encompass two distinct categories: (1) clinician's interview-based global severity scales, and (2) clinician's interview-based global change scales. The global severity scales that have been used include: the Clinical Dementia Rating (CDR) and the related CDR-sum of boxes (CDR-SB), the Global Deterioration Scale (GDS), and the Functional Assessment Staging (FAST) procedure. The global severity scales are clearly useful in subject categorization in treatment trials, in part because they are relatively free of many of the sociocultural biases inherent in mental status and psychometric descriptors. Global severity scales can also be used to demonstrate therapeutic efficacy in terms of the general progression of the dementia process. These measures have also proven to be useful in sensitively assessing pharmacotherapeutic effects in Alzheimer's disease (AD) treatment trials. For example, in pivotal trials: (1) in Mild to Moderate AD, the GDS has shown significant change in response to medication, whereas the results on the Mini-mental State Examination (MMSE) were not significant, and (2) in Moderate to Severe AD, the FAST has shown significant pharmacotherapeutic efficacy, whereas the results using the MMSE were not significant. The global change scales employed in dementia trials differ widely in assessment methodology. Clinical Global Impressions of Change (CGIC) scales do not have defined methodologies, whereas Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) scales are much more elaborate. The CIBIC-Plus procedures require an independent clinician assessment and can provide independent, comprehensive evidence of therapeutic efficacy. The CIBIC-Plus procedure may also be useful in sensitively assessing efficacy in future prevention trials, for example in subjects with Subjective Cognitive Impairment. For Mild Cognitive Impairment (MCI), global severity scales already appear to be one modality for the sensitive assessment of change. The CIBIC-Plus procedures might also productively be applied in future MCI therapeutic trials.

Should One Use Medications in Combination With Cognitive Training? If So, Which Ones?

In this article, we review current research regarding diagnosis of cognitive impairment in nondemented adults and discuss why medications and cognitive training together may be more beneficial than either alone. We also review potential cognitive enhancers and future research challenges. There are major reasons for such research: (a) Large numbers of older adults without dementia but with cognitive problems are not treatable with current cognitive training techniques; (b) some medications offer a rationale (i.e., cognitive enhancement) and some evidence that they might be a useful adjunct; and (c) there are unanswered questions about which population to target, which medications to use, how to administer them, and issues regarding tolerance and use of appropriate (active) placebo controls. As the number of cognitively impaired older adults grows, it is likely that there will be pressure to treat more broadly with both medications and cognitive training.

Memantine reduces oxidative damage and enhances long-term recognition memory in aged rats

Many neurodegenerative diseases, including Alzheimer's (AD), Parkinson's (PD) and Huntington's diseases (HD), are caused by different mechanisms but may share a common pathway to neuronal injury as a result of the overstimulation of glutamate receptors. It has been suggested that this pathway can be involved in generation of cognitive deficits associated with normal aging. Previous studies performed in our laboratory have demonstrated that aged rats presented recognition memory deficits. The aim of the present study was to evaluate the effect of memantine, a low-affinity N-methyl-D-aspartate (NMDA) receptor antagonist, on age-induced recognition memory deficits. Additionally, parameters of oxidative damage in cerebral regions related to memory formation were evaluated. In order to do that, male Wistar rats (24 months old) received daily injections of saline solution or memantine (20 mg/kg i.p.) during 21 days. The animals were submitted to a novel object recognition task 1 week after the last injection. Memantine-treated rats showed normal recognition memory while the saline group showed long-term recognition memory deficits. The results show that memantine is able to reverse age-induced recognition memory deficits. We also demonstrated that memantine reduced the oxidative damage to proteins in cortex and hippocampus, two important brain regions involved in memory formation. Thus, the present findings suggest that, at least in part, age-induced cognitive deficits are related to oxidative damage promoted by NMDA receptor overactivation.

Preclinical investigation of the functional effects of memantine and memantine combined with galantamine or donepezil

Combinations of drugs approved to treat Alzheimer's disease (AD) were tested in older rabbits with delay eyeblink classical conditioning, a form of associative learning severely impaired in AD. In Experiment 1 (n=49 rabbits), low doses (0.1, 0.5, 1.0, and 0.0 (vehicle) mg/kg) of memantine (Namenda) were tested. These three doses neither improved nor impaired acquisition at a statistically significant level. The 0.5 mg/kg dose had the greatest effect numerically and did not cause sensitization or habituation in explicitly unpaired controls. In Experiment 2 (n=56), doses of galantamine (Razadyne; 3.0 mg/kg) and donepezil (Aricept; 0.75 mg/kg) that had comparable magnitudes of cholinesterase inhibition were tested alone and in combination with 0.5 mg/kg memantine. Older rabbits treated with galantamine and with galantamine+memantine learned significantly better than vehicle-treated rabbits, but adding memantine did not improve learning over galantamine alone. Older rabbits treated with donepezil or a combination of memantine and donepezil did not learn significantly better than rabbits treated with vehicle. Galantamine has two mechanisms of action: mild cholinesterase inhibition and allosteric modulation of nicotinic acetylcholine receptors (nAChRs). When equated for cholinesterase inhibition, galantamine had significant efficacy in the eyeblink conditioning model system, but donepezil did not, indicating that modulation of nAChRs may be the mechanism that significantly ameliorates learning deficits in this model. In the absence of AD neuropathology in older rabbits, memantine had no efficacy alone or in combination with the other drugs.

Potential ethnic modifiers in the assessment and treatment of Alzheimer's disease: challenges for the future

OBJECTIVE

Despite numerous clinical trials, it is unknown whether ethnicity affects treatment response to cognitive enhancers in Alzheimer's disease (AD). There is convincing evidence of ethnic and genetic variability in drug metabolism. This article reviews the available data on ethnicity in clinical trials for AD to answer two questions: (1) what are the challenges to diagnose and treat AD across different ethnic groups, and (2) are there differences in response to pharmacologic interventions for AD across these different ethnic groups?

METHOD

Available data from Alzheimer's Disease Cooperative Study (ADCS) randomized controlled clinical trials and from randomized controlled industry-sponsored trials for four cognitive enhancers (donepezil, galantamine, rivastigmine and sabeluzole) were pooled to assess the numbers of non-Caucasian participants.

RESULTS

The participation of ethnic minority subjects in clinical trials for AD was dependent on the funding source, although Caucasian participants were over-represented and non-Caucasian participants were under-represented in the clinical trials. Because of the low participation rate of ethnic minorities, there were insufficient data to assess any differences in treatment outcome among different ethnic groups. Strategies to improve diversity in clinical trials are discussed.

CONCLUSION

Greater participation of ethnically diverse participants in clinical trials for AD would generate additional information on possible differences in metabolism, treatment response, adverse events to therapeutic agents, and could foster the investigation of genetic variability among ethnic groups.

Dementia assessment and management

Dementia is a common yet potentially underdiagnosed illness in the long-term care setting. Targeted screening for dementia should be routine practice, as a diagnosis of dementia will have benefits to the care of the patient. Assessment of dementia should proceed in a step-wise approach and should be tailored to the needs of the individual patient. Management of dementia involves care for the cognitive changes, behavioral changes, functional changes, and emotional issues. It also involves the management of other illnesses in light of the dementia, consideration of the needs and well-being of the caregiver, and particular attention to advanced care planning. Management techniques and goals should evolve as the patient's illness progresses. This comprehensive approach to management of dementia may reduce morbidity and mortality associated with this illness. This model of care provides patients and families with needed information and resources, a clear view of prognosis, and necessary attention to quality of life issues.

A double-blind, placebo-controlled trial of memantine in age-associated memory impairment (memantine in AAMI)

OBJECTIVES

To determine the safety and efficacy of memantine in treating Age-Associated Memory Impairment (AAMI).

METHODS

Sixty adults between 50-79 years of age meeting diagnostic requirements for AAMI were randomly assigned to either memantine (titrated to 20 mg) or a matched placebo and treated for 90 days. An extensive battery of computerized cognitive tests was administered at screening, baseline and, thereafter, at monthly intervals.

RESULTS AND CONCLUSION

Study results suggest that the primary cognitive effects of memantine in this population are on attention and information processing speed, rather than on memory. There were no differences in adverse events between memantine and placebo.

Cost-effectiveness of memantine in moderate-to-severe Alzheimer's disease patients receiving donepezil

OBJECTIVE

The efficacy and safety of memantine in patients with moderate-to-severe Alzheimer's disease (AD) receiving stable doses of donepezil were recently demonstrated in a phase III trial. The cost-effectiveness of such therapy is unknown.

RESEARCH DESIGN AND METHODS

A microsimulation model was developed to depict AD progression over time and associated clinical and economic outcomes. AD progression was measured in terms of decline in cognitive function, as assessed by the Severe Impairment Battery (SIB). At model entry, patients were assumed to have moderate-to-severe AD, to be on stable doses of donepezil, and to begin combination therapy with memantine, or continue to receive donepezil alone; duration of therapy was assumed to be 1 year. Drug efficacy was based on data from a phase III trial. Key assumptions of the model included: (1) efficacy of study drugs would extend to 1 year; (2) measures of cognitive function could be mapped to one another, as well as to global measures of disease severity; and (3) following therapy discontinuation, cognitive function would revert immediately to natural history levels. Cost-effectiveness was assessed in terms of cost (2005 US$) per quality-adjusted life-year (QALY) gained over a lifetime (3% discount rate).

RESULTS

SIB scores were estimated to improve by 3.3 over 1 year from therapy with memantine plus donepezil (vs. donepezil alone). While pharmacotherapy costs were estimated to increase by $1250 during the year of memantine treatment, costs of formal and informal services were estimated to decrease by $1240 over this period and by $1493 (discounted present value) over a lifetime. Findings were sensitive to the assumed SIB score at therapy initiation; cost-effectiveness was better for patients with higher initial SIB scores (i.e., less severe disease).

CONCLUSION

In patients with moderate-to-severe AD already receiving donepezil, treatment with memantine results in improved clinical outcomes and reduced total costs of care.

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.

Functional outcomes of drug treatment in Alzheimer's disease: A systematic review and meta-analysis

BACKGROUND

Patient functioning is an important outcome in Alzheimer's disease, but treatment-related improvements in patient function are difficult to quantify because a number of different scales are used in its measurement.

OBJECTIVE

To evaluate systematically the evidence relating to patient functioning as an outcome measure in the drug treatment of Alzheimer's disease. Data were obtained by searching MEDLINE, EMBASE, The Cochrane Library and the International Pharmaceutical Abstracts from 1980 through to December 2005 for studies assessing functional outcomes with donepezil, galantamine, rivastigmine and memantine in Alzheimer's disease. Reference lists were searched manually and pharmaceutical manufacturers were invited to submit dossiers. Trained reviewers abstracted data and assessed the internal validity (quality) of trials using predefined criteria. Standardised effect sizes (i.e. Cohen's standardised mean difference [d]) for various functional outcome scales and pooled mean incidence and 95% CIs for adverse events were calculated and summarised qualitatively and quantitatively. Meta regression was used to explore potential heterogeneity.

RESULTS

Overall, the standardised effect size for functional outcome measures was small (d = 0.1-0.4) among included studies. However, effect sizes consistently favoured drug treatment over placebo. For all drugs, pooled standardised effect sizes were consistent in both short (<24 weeks; d = 0.25; 95% CI 0.13, 0.37) and long trials (>or=24 weeks; d = 0.29; 95% CI 0.22, 0.36). The pooled effect size was not significantly affected by parameters such as disease severity, age, gender and drug dose. Adverse events were generally limited to gastrointestinal problems, weight loss and dizziness, all of which were reported in <20% of patients on average.

CONCLUSIONS

Standardised estimates of effect size across diverse functional outcome measures for drug treatment in patients with Alzheimer's disease were small and the data reflect only a modest trend favouring active treatment over placebo. However, given the current lack of other effective treatments for Alzheimer's disease, this trend supports the clinical benefits of these treatments with regard to this important health outcome.

Pharmacological treatment of the psychosis of Alzheimer's disease: what is the best approach?

Psychosis of Alzheimer's disease (PAD) forms part of the behavioural and psychological symptoms of dementia (BPSD). PAD includes symptoms of psychosis such as hallucinations or delusions, and may be associated with agitation, negative symptoms or depression. Even though the US FDA has not approved any medication for the treatment of PAD, atypical antipsychotics have been widely used and favoured by geriatric experts in the management of the condition in view of their modest efficacy and relative safety. However, the recent FDA warnings regarding the cardiac, metabolic, cerebrovascular and mortality risks associated with the use of these drugs in elderly patients with dementia have caused serious concerns regarding their use. Nevertheless, until an effective and safe medication is approved by the regulatory agencies for PAD, clinicians do not have a better choice than atypical antipsychotics for the management of the serious symptoms of this condition.

Memantine: efficacy and safety in mild-to-severe Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia, accounting for 25 million cases worldwide. Until recently, the pharmacotherapy of AD was limited to the use of cholinesterase inhibitors (ChEIs) that are approved only for the mild to moderate stages of the illness. Memantine, an NMDA receptor antagonist has been found to be effective, both as monotherapy and in combination with donepezil, in the treatment of patients with moderate to severe stage AD. More recent studies have examined the role of memantine in the treatment of the mild to moderate stages of the disease, although the collective results of these studies remain inconclusive. Available pharmacoeconomic data indicate that treatment with memantine is cost-effective when compared with no treatment in patients with moderate to severe AD. Memantine treatment is predicted to be associated with lower costs of care, longer time to dependence and institutionalization, and gains in quality-adjusted life-years. In this article, we review the evidence for the use of memantine in patients with AD, ranging from the mild to severe stages of disease.

Dementia syndromes: evaluation and treatment

As our population ages, diseases affecting memory and daily functioning will affect an increasing number of individuals, their families and the healthcare system. The social, financial and economic impacts will be profound. This article provides an overview of current dementia syndromes to assist clinicians in evaluating, educating and treating these patients.

A 24-week randomized, controlled trial of memantine in patients with moderate-to-severe Alzheimer disease

This study examined the efficacy and safety of memantine monotherapy in patients with moderate-to-severe Alzheimer disease (AD). Patients not receiving a cholinesterase inhibitor (N=350) were randomized to receive memantine (20 mg/d) or placebo during this 24-week, double-blind, placebo-controlled trial. Prospectively defined analyses failed to demonstrate a statistically significant benefit of memantine treatment compared with placebo on the Severe Impairment Battery (SIB) at week 24 end point, although a significant advantage was observed for memantine at weeks 12 and 18. The 19-item Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL19) did not differ significantly between groups in any analysis. Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC-Plus) did not significantly favor memantine at week 24 despite a significant advantage for memantine at weeks 12 and 18. Other secondary outcomes showed no significant treatment differences. Post hoc analyses of potentially confounding covariates and alternative methods of imputing missing data did not substantially alter the results. Because of the violations of normality assumptions for the SIB and ADCS-ADL19, nonparametric analyses were performed; statistically significant benefit of memantine over placebo was demonstrated at week 24 for the SIB but not the ADCS-ADL19. The type and incidence of adverse events were similar in both groups.

Open label, multicenter, 28-week extension study of the safety and tolerability of memantine in patients with mild to moderate Alzheimer’s disease

BACKGROUND

Memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been shown to be safe and to have beneficial effects on cognition, function, behavior, and global patient status in patients with Alzheimer's disease (AD) in studies lasting 3-6 months. It is approved in the U.S. and Europe for the treatment of moderate to severe AD and is currently under investigation for mild to moderate AD.

OBJECTIVE

To evaluate the long-term safety of memantine in patients with mild to moderate AD and to investigate the tolerability of once-daily dose administration.

METHODS

This 28-week study enrolled 314 patients with mild to moderate AD who had completed a 24-week, double-blind, placebo-controlled lead-in clinical trial of memantine in AD. Following an 8-week double-blind dose titration phase (used to assess the tolerability of different dosing regimens), subjects were assigned to continuous open label memantine (10 mg, bi.d.) treatment for 20 weeks. Safety outcome measures included treatment-emergent adverse events (AEs), deaths, vital signs, electrocardiograms, and laboratory parameters.

RESULTS

During the 28-week study (Phase A+Phase B), the most common AEs were falls and other injuries (both 10.8%). AEs resulted in treatment discontinuation in 6.7% of patients. Discontinuations due to AEs were similar in the once-daily dosing groups compared to the twice-daily dosing groups. During dose titration, completion rates were greater than 90% for both groups. Conversion to once-daily dosing in patients already receiving twice-daily doses of memantine was also well tolerated.

CONCLUSIONS

Memantine monotherapy in patients with mild to moderate AD is safe and well tolerated for at least one year. Once-daily dosing during titration and short-term maintenance therapy is safe and well tolerated.

Safety and tolerability of once-daily versus twice-daily memantine: a randomised, double-blind study in moderate to severe Alzheimer's disease

OBJECTIVE

To assess the safety and tolerability of three different dosing schedules of memantine in patients with moderate to severe Alzheimer's disease (AD).

METHOD

This 12-week, randomised, double-blind study, investigated three dosing schedules of memantine: OD1 (20 mg once daily with a 1-step up-titration); OD3 (20 mg once daily with a 3-step up-titration); and BID3 (10 mg twice daily with a 3-step up-titration as currently recommended in the memantine labelling). The study comprised 78 patients with moderate to severe AD (DSM-IV-TR criteria; MMSE score < or = 18), 70% of whom were on stable dosing of acetylcholinesterase inhibitor (AChEI) initiated > or = 3 months prior to study start. Safety and tolerability were assessed by the number of withdrawals, adverse events (AEs) and monitoring of vital signs.

RESULTS

The number of patient withdrawals was low: 3 of 27 in OD1, 1 of 25 in OD3 and 2 of 26 in BID3. One or more AEs were reported in 9 patients in OD1, 7 patients in OD3 and 12 patients in BID3. Most AEs were mild or moderate, and typical for the population studied; no clinically important differences in AEs or vital signs were observed between the different dosing schedules. There were no between-group differences in efficacy, as assessed by clinical global severity and clinical global change. These results are consistent with the good safety profile of memantine observed in larger studies.

CONCLUSIONS

Although relatively small in size, the study indicates that once-daily dosing and twice-daily dosing of memantine are similar in terms of safety and tolerability.

The Utility of PET Brain Imaging in the Initial Evaluation of Dementia

Given the challenges and benefits of timely and accurate diagnosis of neurodegenerative disorders and the importance of appropriate subsequent treatments, physicians and patients alike desire tools that aid in diagnosing dementia as early and as precisely as possible. One of these tools may be functional brain imaging, specifically positron emission tomography (PET). Recent technological advancements, ongoing research studies, and approval for reimbursement by various insurance companies and Medicare, under certain circumstances, have led to an increased interest in the use of this tool in the evaluation of dementia. This article will review PET brain imaging in the initial assessment and diagnosis of dementia, including its place in current guidelines and role in diagnostic algorithms, its applicability in differentiating among various dementia syndromes and major psychiatric disorders, and some of the controversies surrounding its utility in general clinical practice.

Treatment Strategies for the Behavioral Symptoms of Alzheimer's Disease: Focus on Early Pharmacologic Intervention

The impact of behavioral symptoms associated with Alzheimer's disease is substantial. These symptoms contribute to diminished quality of life for patients and caregivers and increase the cost of care in nursing homes. Early recognition of behavioral symptoms and appropriate treatment are important for successful management. Nonpharmacologic strategies remain the cornerstone of the management of Alzheimer's disease-related behavioral symptoms. However, nonpharmacologic strategies may not be effective for problem behaviors, and pharmacologic intervention may be necessary. Relevant articles were identified through various MEDLINE searches with no date restrictions, with an emphasis on recent studies that used cholinesterase inhibitors and memantine. Additional reports of interest were identified from the reference lists of these articles. To facilitate cross-study analyses in the review of cholinesterase inhibitors and memantine, the database search was limited to randomized, placebo-controlled trials that used the Neuropsychiatric Inventory to assess behavioral symptoms of Alzheimer's disease. Overall, evidence from trials of cholinesterase inhibitors and memantine suggests that when these agents are optimized for the various stages of Alzheimer's disease, they can also prevent the emergence of neuropsychiatric symptoms. Although results from the literature are not uniformly positive, cholinesterase inhibitors have been shown to produce significant improvements in behavioral symptoms in patients with both mild- to-moderate and moderate-to-severe Alzheimer's disease. Evidence also indicates that memantine might be of benefit as an adjunct to long-term cholinesterase inhibitor treatment in patients with moderate-to-severe Alzheimer's disease and that memantine monotherapy may have some beneficial effects on behavior in patients with mild-to-moderate disease. Of importance, although no direct comparisons have been performed, these agents seem to have an improved safety and tolerability profile compared with the frequently used antipsychotic drugs. When nonpharmacologic strategies are deemed insufficient to ease problem behaviors in patients with Alzheimer's disease, treatment with cholinesterase inhibitors, alone or in combination with memantine as appropriate for the stage of disease, may be considered as a first-line option in the early pharmacologic management of Alzheimer's disease-related behavioral symptoms.

Memantine in the treatment of mild-to-moderate Alzheimer's disease

Memantine is the first and only medication that has been approved by European, US and Canadian regulatory agencies for the treatment of moderate-to-severe Alzheimer's disease (AD). It is an NMDA receptor antagonist that works to prevent excitotoxicity and cell death, which are mediated by the excessive influx of calcium during a sustained release of glutamate. Preclinical studies of memantine reveal that it has the potential to improve memory and learning processes after impairment has occurred, as well as to prevent further neuronal damage. Although memantine has been considered for the treatment of earlier AD, it has not yet been approved for this. Randomized controlled trials of memantine in the treatment of mild-to-moderate AD have demonstrated small treatment effects in measures of cognition, global assessment and behavior favoring the use of memantine. However, the differences between treatment groups were not consistently significant. Two ongoing long-term trials are further investigating the efficacy of memantine in the treatment of mild-to-moderate AD.

Activities of daily living in moderate-to-severe Alzheimer disease: an analysis of the treatment effects of memantine in patients receiving stable donepezil treatment

In moderate-to-severe Alzheimer disease (AD), there are significant losses of activities of daily living (ADL). In a recent prospective, randomized, placebo-controlled trial, memantine treatment lessened the overall functional decline in AD patients already on stable donepezil therapy. In this trial, patients (n=404) with Mini-Mental State Examination scores of 5 to 14 receiving stable donepezil treatment were randomized to double-blind treatment with memantine (10 mg b.i.d.; n=203) or placebo (n=201). A primary outcome measure was the 19-item Alzheimer's Disease Cooperative Study--Activities of Daily Living Inventory (ADCS-ADL(19)). To further evaluate the treatment effects of memantine on function, we performed post hoc analyses of ADCS-ADL(19) data from this trial, including ADL items and new subscales derived from factor analysis. Using mixed model analyses, patients receiving memantine had statistically significant less decline in total ADCS-ADL(19) scores compared with placebo. An item analysis revealed statistically significant benefits of memantine on grooming, toileting, conversing, watching television, and being left alone. Statistically significant improvements were noted in subscales evaluating higher-level functions and connectedness/autonomy with memantine compared with placebo. These post hoc analyses in moderate-to-severe AD patients receiving stable donepezil treatment suggest that memantine may impact overall functional levels, and some of the cognitive processing underlying ADL performance.

Association between amantadine and the onset of dementia in Parkinson's disease

The objective of this study is to compare the occurrence of dementia among Parkinson's disease (PD) patients treated with amantadine (AM group) with those never exposed to it (NoAM group). PD dementia shares neuroanatomical and biochemical similarities with Alzheimer's disease (AD). Memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist has been shown to be beneficial in AD. Memantine is a dimethyl derivative of amantadine, which also possesses NMDA receptor blocking properties. We hypothesized that amantadine could have a beneficial effect on the occurrence of PD dementia. PD patients attending the Movement Disorders Clinics in Hillel Yaffe, Asaf Harofe Medical Centers (Israel) and Pisa (Italy) were included. Taking the onset of dementia as the endpoint, survival curves for AM and NoAM patients were estimated by the Kaplan-Meier method. The study population consisted of 593 patients (age, 69.5 +/- 9.9 years; PD duration, 9.2 +/- 6.0 years; 263 patients (44%) amantadine treated). The endpoint of dementia was reached by 116 patients (20%). PD duration until dementia was significantly longer for AM patients (9.1 +/- 5.7 years) than for NoAM patients (5.9 +/- 4.6 years, P = 0.006). The duration of amantadine exposure positively correlated with PD duration until dementia (P = 0.0001). Survival analysis, taking dementia onset as endpoint, showed slower mental decline in AM patients (Log rank P = 0.0049, Wilcoxon P = 0.0024). Mini-Mental State Examination scores were significantly higher for AM patients than for the NoAM group (P = 0.01). Age of PD onset also significantly influenced the duration of PD until dementia. Amantadine use may delay the onset of dementia in PD patients and may attenuate its severity.

Distinguishing delirium and dementia

Delirium and dementia are syndromes with multiple cognitive impairments common to the elderly and to medically ill patients. While strides have been made in recognition of both delirium and dementia, underdiagnosis is common. Delirium and dementia cause great suffering in patients, families and caregivers. Both necessitate further advancement in assessment methods and treatment, especially when they overlap. Differentiating delirium and dementia requires recognizing that both may present with cognitive, behavioral and neuropsychiatric symptoms, but attentional disturbance and acute onset are cardinal discriminators in delirium. Superimposed delirium on dementia presents a particularly vexing problem in terms of recognition, treatment and prognosis. The pathophysiology of delirium results from diffuse cortical dysfunction or impairment in susceptible areas of the cortex and the reticular activating system. The pathophysiology of dementia is varied across dementias although several share histolological features. Treatment for both delirium and dementia includes antipsychotic medications and cholinesterase inhibitors, among others, although the disadvantages of pharmacological treatment are becoming better understood and demand caution. Nevertheless, there is an array of treatments and preventive strategies being explored for dementia, and to a lesser degree for delirium, that hold promise for the future.

Treatment of Cognitive Decline and Psychiatric Disturbances Associated With Alzheimer's Dementia

Alzheimer's dementia (AD) is the most common type of dementia. In addition to the cognitive and functional disturbances that happen as the disease progresses, other psychological disturbances may manifest. Depression, insomnia, anxiety, and psychosis are among several psychological conditions which can occur concomitantly with AD. These changes can result in decreased quality of life for both patients and caregivers, increase caregiver burden, and impact the decision to place a patient with AD into a long-term care facility. An evidence-based review of the literature was performed to ascertain if a specific recommendation for pharmacotherapy can be made based on current research in this specific patient population.

Alzheimer's disease: progress in the development of anti-amyloid disease-modifying therapies

The amyloid hypothesis--the leading mechanistic theory of Alzheimer's disease--states that an imbalance in production or clearance of amyloid beta (Abeta) results in accumulation of Abeta and triggers a cascade of events leading to neurodegeneration and dementia. The number of persons with Alzheimer's disease is expected to triple by mid-century. If steps are not taken to delay the onset or slow the progression of Alzheimer's disease, the economic and personal tolls will be immense. Different classes of potentially disease-modifying treatments that interrupt early pathological events (ie, decreasing production or aggregation of Abeta or increasing its clearance) and potentially prevent downstream events are in phase II or III clinical studies. These include immunotherapies; secretase inhibitors; selective Abeta42-lowering agents; statins; anti-Abeta aggregation agents; peroxisome proliferator-activated receptor-gamma agonists; and others. Safety and serious adverse events have been a concern with immunotherapy and gamma-secretase inhibitors, though both continue in clinical trials. Anti-amyloid disease-modifying drugs that seem promising and have reached phase III clinical trials include those that selectively target Abeta42 production (eg, tarenflurbil), enhance the activity of alpha-secretase (eg, statins), and block Abeta aggregation (eg, transiposate).

A pilot evaluation of the safety, tolerability, pharmacokinetics, and effectiveness of memantine in pediatric patients with attention-deficit/hyperactivity disorder combined type

BACKGROUND

Disturbances in N-methyl-D-aspartate (NMDA) receptor activity may play a role in attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE

This study is a preliminary evaluation of the safety, pharmacokinetics, and effectiveness of the NMDA receptor antagonist memantine in pediatric ADHD.

METHODS

An open-label, dose-finding, 8-week, trial in outpatients 6-12 years old with ADHD combined type. Memantine oral solution (2 mg/mL) was titrated to 10 mg/day (n = 8) or 20 mg/day (n = 8). Safety data and blood samples for pharmacokinetic analyses were collected. The ADHD Rating Scale-IV (ADHD-IV) and Clinical Global Impression of Severity (CGI-S) scale measured the effectiveness of memantine.

RESULTS

There were no discontinuations due to adverse events (AEs), serious AEs, deaths, or suicides. Most AEs were mild and occurred during the first week of treatment. The 20 mg/day memantine dose was associated with a higher rate of completion and larger mean improvement on the ADHD-IV and CGI-S than 10 mg/day memantine. Pharmacokinetic analyses suggest response to memantine may be dose-dependent beyond an initial threshold concentration.

CONCLUSIONS

This pilot study suggests that a memantine dose of 20 mg/day may be a safe and possibly effective treatment for pediatric ADHD. Further investigations of memantine in ADHD appear to be warranted.

Palliative Care for the Older Adult

The majority of deaths in the United States occur in the geriatric population. These older adults often develop multiple chronic medical problems and endure complicated medical courses with a variety of disease trajectories. Palliative care physicians need to be skilled in addressing the needs of these frail elders with life-limiting illness as they approach the end of life. Although geriatrics and palliative medicine share much in common, including an emphasis on optimizing quality of life and function, geriatric palliative care is distinct in its focus on the geriatric syndromes and on the provision of care in a variety of long-term care settings. Expertise in the diagnosis and management of the geriatric syndromes and in the complexities of long-term care settings is essential to providing high-quality palliative care to the elderly patient. This paper is a practical review of common geriatric syndromes, including dementia, delirium, urinary incontinence, and falls, with an emphasis on how they may be encountered in the palliative care setting. It also highlights important issues regarding the provision of palliative care in different long-term care settings.

Potential role of N-methyl-D-aspartate receptors as executors of neurodegeneration resulting from diverse insults: focus on memantine

Glutamatergic neurotransmission is critical to normal learning and memory and when the activity of glutamate neurons becomes excessive, or the normal function of its primary receptors becomes dysfunctional, this may lead to pathological changes associated with age-related neurodegenerative diseases. Anomalous glutamatergic activity associated with Alzheimer's disease may be due to a postsynaptic receptor and downstream defects that produce inappropriately timed or sustained glutamate activation of N-methyl-D-aspartate receptors, leading to neuronal injury and death and cognitive deficits associated with dementia. The mechanisms leading to the condition of chronically depolarized membranes on vulnerable neurons in the Alzheimer's disease brain are likely due to a complex interaction between oxidative stress, mitochondrial failure, chronic brain inflammation and the presence of amyloid-beta and hyperphosphorylated-tau; each of these factors are highly interrelated with each other and are discussed with an emphasis upon potential therapeutic mechanisms underlying the neuroprotective actions of memantine.

Interaction study of aspirin or clopidogrel on pharmacokinetics of donepezil hydrochloride in rats by HPLC-fluorescence detection

The present study aims to investigate the possibility of interaction of aspirin (Asp) or clopidogrel (CG) on donepezil (DP) hydrochloride in rats by HPLC-fluorescence detection. The separation of DP was achieved in ca. 13 min without interference of Asp and CG on the chromatogram. DP levels in rat plasma with a single administration of DP (5 mg/kg, i.p., group I) and those with a co-administration of Asp (200 mg/kg, p.o., group II or 200 mg/kg, i.p., group III) or CG (5 mg/kg, p.o., group IV) were monitored. The DP concentrations determined in rat plasma ranged from 25.0 to 336.1 ng/mL. Pharmacokinetic parameters for these groups were calculated and compared with one another. No significant difference was observed on the comparison of group I with other groups except for the mean resident time of group IV (p = 0.012). These basic findings may help clinical inference when DP is co-administered with Asp and CG to human.

Evaluated Need, Costs of Care, and Payer Perspective in Degenerative Dementia Patients Cared for in the United States

The purpose of this study was to examine the strength of the associations between 5 measures of need that are potentially modifiable in degenerative dementia patients and direct costs of care from 5 payer perspectives in the US healthcare system. Data were derived from a cohort study of 150 patients with a degenerative dementia. We measured need variables at baseline and utilization of healthcare in the year before and after baseline. Utilization data were converted into estimated direct costs and totaled based on the costs paid for by 5 payers in the US healthcare system. Path models were used to quantify and compare the relationships between need variables and direct costs. From Medicare's perspective, comorbid medical conditions were the most important predictor of Medicare costs. From Medicaid's perspective, neuropsychiatric symptoms and signs of parkinsonism were additional significant predictors. From the perspective of patients, their families and society, all 5 need variables were significant predictors of direct costs (ie, those above, plus cognitive impairment, and dependency). The relationship between evaluated need variables and direct costs depends on the perspective of the payer and provide insights into which need variables could be targeted with interventions to control costs and improve patient outcomes.

Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline

The aim of this international guideline on dementia was to present a peer-reviewed evidence-based statement for the guidance of practice for clinical neurologists, geriatricians, psychiatrists, and other specialist physicians responsible for the care of patients with dementia. It covers major aspects of diagnostic evaluation and treatment, with particular emphasis on the type of patient often referred to the specialist physician. The main focus is Alzheimer's disease, but many of the recommendations apply to dementia disorders in general. The task force working group considered and classified evidence from original research reports, meta-analysis, and systematic reviews, published before January 2006. The evidence was classified and consensus recommendations graded according to the EFNS guidance. Where there was a lack of evidence, but clear consensus, good practice points were provided. The recommendations for clinical diagnosis, blood tests, neuroimaging, electroencephalography (EEG), cerebrospinal fluid (CSF) analysis, genetic testing, tissue biopsy, disclosure of diagnosis, treatment of Alzheimer's disease, and counselling and support for caregivers were all revised when compared with the previous EFNS guideline. New recommendations were added for the treatment of vascular dementia, Parkinson's disease dementia, and dementia with Lewy bodies, for monitoring treatment, for treatment of behavioural and psychological symptoms in dementia, and for legal issues. The specialist physician plays an important role together with primary care physicians in the multidisciplinary dementia teams, which have been established throughout Europe. This guideline may contribute to the definition of the role of the specialist physician in providing dementia health care.

Memantine as an example of a fast, voltage-dependent, open channel N-methyl-D-aspartate receptor blocker

Electrophysiological techniques can be used to great effect to help determine the mechanism of action of a compound. However, many factors can compromise the resulting data and their analysis, such as the speed of solution exchange, expression of additional ion channel populations including other ligand-gated receptors and voltage-gated channels, compounds having multiple binding sites, and current desensitization and rundown. In this chapter, such problems and their solutions are discussed and illustrated using data from experiments involving the uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist memantine. Memantine differs from many other NMDA receptor channel blockers in that it is well tolerated and does not cause psychotomimetic effects at therapeutic doses. Various electrophysiological parameters of NMDA-induced current blockade by memantine have been proposed to be important in determining therapeutic tolerability, potency, onset and offset kinetics, and voltage dependency. These were all measured using whole cell patch-clamp techniques using hippocampal neurons. Full results are shown here for memantine, and these are summarized and compared with those from similar experiments with other NMDA channel blockers. The interpretation of these results is discussed, as are theories concerning the tolerability of NMDA channel blockers, with the aim of illustrating how electrophysiological data can be used to form and support a physiological hypothesis.

Disease modifying therapy for AD?

Alzheimer's disease (AD) is the most common form of dementia in industrialized nations. If more effective therapies are not developed that either prevent AD or block progression of the disease in its very early stages, the economic and societal cost of caring for AD patients will be devastating. Only two types of drugs are currently approved for the treatment of AD: inhibitors of acetyl cholinesterase, which symptomatically enhance cognitive state to some degree but are not disease modifying; and the adamantane derivative, memantine. Memantine preferentially blocks excessive NMDA receptor activity without disrupting normal receptor activity and is thought to be a neuroprotective agent that blocks excitotoxicty. Memantine therefore may have a potentially disease modifying effect in multiple neurodegenerative conditions. An improved understanding of the pathogeneses of AD has now led to the identification of numerous therapeutic targets designed to alter amyloid beta protein (Abeta) or tau accumulation. Therapies that alter Abeta and tau through these various targets are likely to have significant disease modifying effects. Many of these targets have been validated in proof of concept studies in preclinical animal models, and some potentially disease modifying therapies targeting Abeta or tau are being tested in the clinic. This review will highlight both the promise of and the obstacles to developing such disease modifying AD therapies.

Memantine: a review of its use in Alzheimer's disease

Memantine (Ebixa, Axura, Namenda, Akatinol) is a moderate-affinity, uncompetitive, voltage-dependent, NMDA-receptor antagonist with fast on/off kinetics that inhibits excessive calcium influx induced by chronic overstimulation of the NMDA receptor. Memantine is approved in the US and the EU for the treatment of patients with moderate to severe dementia of the Alzheimer's type. In well designed clinical trials, oral memantine, as monotherapy or in addition to a stable dose of acetylcholinesterase inhibitors, was well tolerated during the treatment of mild to severe Alzheimer's disease for up to 52 weeks. Memantine generally modified the progressive symptomatic decline in global status, cognition, function and behaviour exhibited by patients with moderate to severe Alzheimer's disease in four 12- to 28-week trials. In patients with mild to moderate Alzheimer's disease, data from three 24-week trials are equivocal, although meta-analyses indicate beneficial effects on global status and cognition. Memantine is an effective pharmacotherapeutic agent, and currently the only approved option, for the treatment of moderate to severe Alzheimer's disease.

New developments in mild cognitive impairment and Alzheimer's disease

PURPOSE OF REVIEW

In this paper, we review current concepts of Alzheimer's disease, recent progress in diagnosis and treatment and important developments in our understanding of its pathogenesis with a focus on beta-amyloid both as culprit and therapeutic target.

RECENT FINDINGS

The amyloid cascade hypothesis of Alzheimer's disease pathogenesis continues to predominate with evidence suggesting that small oligomeric forms of Abeta-42 rather than fibrils or senile plaques are the key pathological substrates. The concept of mild cognitive impairment continues to be refined to define better those patients who will progress to Alzheimer's disease. Structural and functional imaging techniques and cerebrospinal fluid biomarkers are gaining acceptance as diagnostic markers of Alzheimer's disease, with a potentially exciting advance being the ability to image amyloid in vivo using novel positron emission tomography ligands. Whilst available treatments afford only symptomatic benefits, disease-modifying treatments may be within reach. Despite the halting of the first amyloid beta-vaccination trial due to adverse effects, amyloid immunotherapy continues to show promise, with new approaches already entering clinical trials. Other therapeutic strategies under investigation include inhibition of beta -and gamma-secretase, key enzymes implicated in Alzheimer's disease pathogenesis.

SUMMARY

Current research demonstrates the potential for diagnostic strategies and disease modifying treatments to follow from an ever more detailed understanding of the molecular mechanisms underlying the pathogenesis of Alzheimer's disease.

Memantine in the treatment of Alzheimer’s disease

Memantine is a moderate-affinity glutamate antagonist that primarily takes action at the N-methyl-D-aspartate receptor site. It has US FDA and European Medicines Agency approval for the treatment of moderate-to-severe Alzheimer’s disease. Memantine replaces Mg2+ at the N-methyl-D-aspartate receptor, blocking pathological glutamate activity but allowing normal glutamate action at this site. Consequently, calcium homeostasis is better maintained, reducing slow after hyperpolarization and preventing neuronal excitotoxicity and cell death. Clinical trials have shown that memantine is generally safe and well tolerated, and have provided evidence for its efficacy as assessed by cognitive, behavioral, functional and global measures. It has also been shown to be well tolerated and effective in the treatment of moderate-to-severe Alzheimer’s disease when patients received previous and ongoing treatment with donepezil. The tolerability and efficacy of memantine is under continued investigation in milder Alzheimer’s disease and other forms of dementia.

Evidence-Based Research in Complementary and Alternative Medicine III: Treatment of Patients with Alzheimer's Disease

This paper presents the novel domain of evidence-based research (EBR) in the treatment of patients with Alzheimer's disease (AD) from the perspective of traditional medicine and of complementary and alternative medicine. In earlier lectures we have described the process of evidence-based medicine as a methodological approach to clinical practice that is directed to aid clinical decision-making. Here, we present a practical example of this approach with respect to traditional pharmacological interventions and to complementary and alternative treatments for patients with AD.

Potentiation of Excitotoxicity in HIV-1 Associated Dementia and the Significance of Glutaminase

HIV-1 Associated Dementia (HAD) is a significant consequence of HIV infection. Although multiple inflammatory factors contribute to this chronic, progressive dementia, excitotoxic damage appears to be an underlying mechanism in the neurodegenerative process. Excitotoxicity is a cumulative effect of multiple processes occurring in the CNS during HAD. The overstimulation of glutamate receptors, an increased vulnerability of neurons, and disrupted astrocyte support each potentiate excitotoxic damage to neurons. Recent evidence suggests that poorly controlled generation of glutamate by phosphate-activated glutaminase may contribute to the neurotoxic state typical of HAD as well as other neurodegenerative disorders. Glutaminase converts glutamine, a widely available substrate throughout the CNS to glutamate. Inflammatory conditions may precipitate unregulated activity of glutaminase, a potentially important mechanism in HAD pathogenesis.

The Primary Care of Alzheimer Disease

Alzheimer disease is the most common cause of progressive irreversible intellectual loss in aging humans. The number of individuals and families affected by this disorder will continue to grow as society ages worldwide. Our understanding of the biology, underlying pathophysiology, and diagnosis of Alzheimer disease has greatly expanded over the past few years and much has been published in these areas. This review focuses on the primary care of this disorder and addresses the "now what" question. Topics examined include limiting excess disability, responding to commonly raised questions of family members, pharmacologic and nonpharmacologic therapeutic options, long-term planning, and caregiver issues.

Treatment effect size of memantine therapy in Alzheimer disease and vascular dementia

The purpose of this paper is to assess the clinical relevance of the significant results reported in clinical trials of memantine therapy for Alzheimer disease (AD) and vascular dementia. We sought to understand what clinically detectable changes would be evident to the patient with dementia, their caregivers, and the treating physician during a trial of memantine therapy. A literature search was performed on MedLine, PsycInfo, and the Cochrane database. The statistically significant findings from the memantine literature were reviewed using treatment effect size as a measure of clinical meaningfulness. There have been 3 phase 2 studies of memantine in dementia, and 6 phase 3 studies published as of August 1, 2005. Of the 6 published phase 3 trials of memantine in dementia; 2 were in mild-moderate vascular dementia, 1 in mild-moderate AD, 2 in moderate-severe AD, and 1 in severe dementia (both AD and vascular dementia). The most convincing evidence of a clinically meaningful treatment effect of memantine therapy is in the moderate-severe AD patient population. Cognition, as measured by the Severe Impairment Battery, had an effect size of 0.32 and 0.49 in the 2 published trials, indicating a small-to-medium effect of the medication. Global, functional, and behavioral scales also showed a small-to-medium response to memantine.

Treatment of dementia: anything new?

PURPOSE OF REVIEW

The aim of this article is to discuss new data on presently approved drugs for dementia, such as cholinesterase inhibitors and memantine, and concerns regarding the use of antipsychotics for treating neuropsychiatric symptoms, as well as to summarize some relevant studies recently published on emerging therapies with potential disease-modifying effects.

RECENT FINDINGS

The main focuses of recent studies of cholinesterase inhibitors and memantine have been on efficacy and safety aspects in extended clinical trials, combined treatments or comparative analysis between agents, and also on potential neuroprotective effects and new indications. Other publications have assessed the evidence of efficacy and the increased risk of cerebrovascular events, rapid cognitive decline, and mortality with the use of antipsychotics in dementia, providing important information in relation to the controversy surrounding its use. Although more studies are warranted, a sizable literature on novel treatment options under investigation is currently available as a result of a better understanding of pathogenesis of dementia.

SUMMARY

So far, there is no established method to predict better responders or long-term benefits with currently approved drugs for treatment of dementia. Recent systematic reviews and new research on current treatment, however, provide valuable information for clinicians, and novel drugs under investigation reveal promising new therapeutic strategies.