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

Update on the use of memantine in Alzheimer's disease

Memantine is a low to moderate affinity N-methyl-D-aspartate receptor (NMDAR) antagonist. The effects of memantine in Alzheimer's disease (AD) have been studied in 7 randomized controlled trials in many post-hoc analyses. Three out of four RCTs in patients with moderate to severe AD (Mini Mental State Examination [MMSE] <14) showed a statistically significant but clinically small positive effect of memantine on cognition, global functioning, activities of daily living (ADL) and neuropsychiatric symptoms. No effects on these outcome measures could be found in the three RCTs studying patients with mild to moderate AD (MMSE 14-24). Two of these studies evaluated the effect of addition of memantine to donepezil. Only the study in patients with mild to moderate AD showed a positive effect of addition of memantine on cognition, ADL, global functioning and neuropsychiatric functioning. Cost-effectiveness of memantine therapy remains controversial. Post-hoc analyses and observational studies suggest some effects on agitation/aggression, delusions or hallucinations. Side effects of memantine are usually mild and seem to be comparable with placebo. In this review, an oversight of pharmacodynamics and pharmacokinetics of memantine is presented. Also, published data concerning efficacy and safety in patients with AD are presented.

Memantine for the treatment of Alzheimer's disease: tolerability and safety data from clinical trials

BACKGROUND

Memantine, a moderate-affinity, uncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors, is the first non-cholinergic agent approved for the treatment of Alzheimer's disease (AD), and the first medication approved in the US and Europe for the treatment of moderate to severe stages of the disease. The objective of this study was to analyse safety and tolerability data from phase III memantine trials and from the open-label extensions of those trials.

METHOD

We conducted an analysis of the pooled data for tolerability and safety from six double-blind, placebo-controlled, memantine trials with a minimum duration of 24 weeks (three trials in mild to moderate AD and three in moderate to severe AD; 20 mg/day; 2311 patients) and four open-label extensions of those trials (two in mild to moderate AD and two in moderate to severe AD; 20 mg/day, 1405 patients), for a total treatment period of up to 2 years.

RESULTS

The analysis revealed that adverse events occurring during both short- and long-term memantine treatment were minimal, and similar in type and frequency to those reported for placebo-treated patients. The most frequently reported adverse events in placebo-controlled trials included agitation (7.5% memantine vs 12.0% placebo), falls (6.8% vs 7.1%), dizziness (6.3% vs 5.7%), accidental injury (6.0% vs 7.2%), influenza-like symptoms (6.0% vs 5.8%), headache (5.2% vs 3.7%) and diarrhoea (5.0% vs 5.6%). Discontinuations due to adverse events were similar in memantine- and placebo-treated groups (8.9% vs 9.8%, respectively).

CONCLUSION

Consistent with the favourable tolerability profile of memantine observed in clinical use, this analysis of pooled safety data indicates that both short- and long-term memantine treatment of patients with AD is safe and well tolerated, with an adverse event profile similar to that of placebo.

Drug therapy in Alzheimer disease: an update for the oral health care provider

Alzheimer disease (AD) is a progressive neurologic disorder that manifests as memory loss, personality changes, global cognitive dysfunction, and functional impairment. As the United States population continues to age, the prevalence of AD will rise. Accordingly, oral health care providers will be more likely to treat patients affected by this disease; therefore, it is necessary to understand the pharmacologic agents used for the management of AD. This article provides an update of the available drug therapies for AD and discusses their implications on the oral and dental health of patients.

Diagnosis and treatment of dementia: 5. Nonpharmacologic and pharmacologic therapy for mild to moderate dementia

BACKGROUND

Practising physicians frequently seek advice on the most effective interventions for dementia. In this article, we provide practical guidance on nonpharmacologic and pharmacologic interventions for the management of mild to moderate dementia based on recommendations from the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia.

METHODS

We developed evidence-based guidelines using systematic literature searches, with specific criteria for the selection and quality assessment of articles, and a clear and transparent decision-making process. We selected articles published from January 1996 to December 2005 that dealt with the management of mild to moderate stages of Alzheimer disease and other forms of dementia. Recommendations based on the literature review were drafted and voted on. Consensus required 80% or more agreement by participants. Subsequent to the conference, we searched for additional articles published from January 2006 to April 2008 using the same major keywords and secondary search terms. We graded the strength of the evidence using the criteria of the Canadian Task Force on Preventive Health Care.

RESULTS

We identified 1615 articles, of which 954 were selected for further study. From a synthesis of the evidence in these studies, we made 48 recommendations for the management of mild to moderate dementia (28) and dementia with a cerebrovascular component (8) as well as recommendations for addressing ethical issues (e.g., disclosure of the diagnosis) (12). The updated literature review did not change these recommendations. An exercise program is recommended for patients with mild to moderate dementia. Physicians should decide whether to prescribe a cholinesterase inhibitor on an individual basis, balancing anticipated benefits with the potential for harm. For mild mood and behavioural concerns, nonpharmacologic approaches should be considered first.

INTERPRETATION

Although the available therapies for dementia can help with the management of symptoms, there is a need to develop more effective interventions.

Pharmacotherapeutic targets in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder which is characterized by an increasing impairment in normal memory and cognitive processes that significantly diminishes a person's daily functioning. Despite decades of research and advances in our understanding of disease aetiology and pathogenesis, there are still no effective disease-modifying drugs available for the treatment of AD. However, numerous compounds are currently undergoing pre-clinical and clinical evaluations. These candidate pharma-cotherapeutics are aimed at various aspects of the disease, such as the microtubule-associated τ-protein, the amyloid-β (Aβ) peptide and metal ion dyshomeostasis – all of which are involved in the development and progression of AD. We will review the way these pharmacological strategies target the biochemical and clinical features of the disease and the investigational drugs for each category.

Effectiveness and safety of donepezil in Hispanic patients with Alzheimer's disease: a 12-week open-label study

BACKGROUND

Hispanics represent 10% of the U.S. population and are the fastest growing group. Studies show a higher prevalence and incidence of Alzheimer's disease (AD) in Hispanics than in the non-Hispanic white population, with an earlier age of onset. Among the currently estimated 200,000 Hispanics with AD, a significant number remain undiagnosed and untreated, and Hispanic participation in AD clinical trials has been historically low. This study evaluated the efficacy and safety of donepezil hydrochloride (donepezil) in Hispanics with mild-to-moderate AD.

METHODS

In this multicenter, open-label, 12-week study conducted in the United States, subjects were Hispanic men or women aged > or =50 years with a diagnosis of mild-to-moderate AD (DSMV-IV and NINCDS/ADRDA criteria), with Mini-Mental State Examination (MMSE) scores of 10-26 (inclusive) at screening. Subjects were treated with donepezil 5 mg/day for 6 weeks followed by 10 mg/day for 6 weeks. Clinical evaluation was performed at baseline, week 6 and week 12. Cognitive improvement was measured using the MMSE, Fuld Object Memory Evaluation (FOME) and Symbol Digit Modality Test (SDMT). Behavioral symptoms and associated caregiver distress were assessed with the Neuropsychiatric Inventory (NPI).

RESULTS

One-hundred-six patients with mild-to-moderate AD (mean age 68.6 years) were enrolled (intent to treat, n=97); most chose to have assessments conducted in Spanish. With 12 weeks of treatment, subjects showed statistically significant improvement from baseline on MMSE (P<0.0001), FOME retrieval (P=0.0042), FOME repeated retrieval (P=0.0020) and SDMT correct scores (P<0.0001). The NPI subdomain "apathy/indifference" showed statistically significant improvement (P=0.0010).The NPI Caregiver Distress scale (NPI-D) total score was statistically significantly improved (P=0.0500), suggesting a positive impact on relieving caregivers' burden associated with patient behavior. Most patients tolerated the treatment well, with only 2 discontinuing because of adverse events. The most common (>5%) adverse events were insomnia (9.5%), dizziness (7.6%), diarrhea (5.7%) and nausea (5.7%).

CONCLUSION

The cognitive improvement and safety results from this study were consistent with those reported for donepezil in the general population. Increased awareness of AD in the Hispanic population will help more Hispanics with AD to benefit from early diagnosis and effective treatment.

Randomized, placebo-controlled, crossover trial of memantine for cognitive changes with corticosteroid therapy

BACKGROUND

In animal models, corticosteroids are associated with changes in hippocampal structure and functioning that are prevented by glutamate release inhibitors or N-methyl-D-aspartate (NMDA) receptor antagonists. Cushing's disease and prescription corticosteroid administration are also associated with memory impairment and hippocampal atrophy. Use of NMDA receptor antagonists to attenuate corticosteroid effects in humans has not been investigated. We examine the NMDA receptor antagonist memantine in patients receiving corticosteroids.

METHODS

Twenty outpatients receiving long-term oral corticosteroid therapy were randomized to 8 weeks of memantine (maximum dose 20 mg/day) and 8 weeks of placebo in a double-blind fashion, with a 4-week washout period between courses. Declarative memory was assessed with the Hopkins Verbal Learning Test (HVLT) and mood with the Hamilton Rating Scale for Depression and Young Mania Rating Scale. Changes in outcome measures were compared during memantine and placebo exposure.

RESULTS

Seventeen participants completed both treatment phases and were used in the analysis. Significant improvement (p < .05) in total and delayed recall on the HVLT was observed with memantine as compared with placebo. No significant changes in mood were observed.

CONCLUSIONS

Memantine therapy was associated with improvement in declarative memory but not mood in patients receiving prescription corticosteroids.

Steady-state pharmacokinetics of rivastigmine in patients with mild to moderate Alzheimer's disease not affected by co-administration of memantine: an open-label, crossover, single-centre study

BACKGROUND AND OBJECTIVE

It has been shown that combining memantine and a cholinesterase inhibitor, which each affect different neurotransmitter systems, may offer further improvements in efficacy over either treatment alone in patients with Alzheimer's disease. The present study was conducted to determine if memantine has any effects on the steady-state pharmacokinetics of rivastigmine in patients with mild to moderate Alzheimer's disease.

METHODS

Rivastigmine-treated Alzheimer's disease patients who had been maintained on a fixed regimen of twice-daily rivastigmine for >or=2 months were eligible to enter the study. Sixteen patients (seven males and nine females, age range 64-88 years, weight range 51.8-104 kg) were enrolled in this open-label, crossover study, which consisted of a 28-day screening period, a 36-hour baseline period, and a 35-day combination treatment phase. The patients spent the baseline period and day 35 at the study centre, where plasma samples for pharmacokinetic evaluation were taken at specified time intervals over a 10-hour time period. In addition, 10-hour (evening pre-dose) memantine plasma samples were taken on days 21, 34 and 35.

RESULTS

The combination of memantine (10 mg twice daily) with rivastigmine (1.5-6 mg twice daily) was safe and well tolerated. At each dose level of rivastigmine, the area under the concentration-time curve (AUC) values of rivastigmine and its metabolite as well as the metabolite-to-parent AUC ratios were unaffected by co-administration of memantine, confirming the absence of a meaningful pharmacokinetic drug-drug interaction.

CONCLUSION

Under the study conditions, the extent of systemic exposure to rivastigmine and its metabolite NAP226-90 at steady state did not appear to be affected by concomitant administration of memantine.

Toward the validation of functional neuroimaging as a potential biomarker for Alzheimer's disease: implications for drug development

Despite investments carried out in the research since Alzheimer's disease (AD) was firstly defined as an isolated clinical entity, there is still a lack of appropriate cure and effective therapies to halt or slow the disease progression. While fundamental research has provided a better characterization of AD, much remains to be done for the development of new biological treatment strategies. It is now being debated whether functional neuroimaging (FNI) could help improve diagnostic accuracy and become a possible biomarker of AD. The primary purpose of this review was to determine whether data already published in the literature meet formal technology assessment standards for using regional cerebral blood flow (rCBF) or glucose metabolism (rCMRGlu) as a biomarker for AD. The secondary purpose was to identify any remaining gaps that might need to be systematically addressed before drug developers and regulators accept FNI as a biomarker for AD. The present paper reviews the literature regarding metabolic positron emission tomography (PET) and perfusion single photon emission computed tomography (SPECT) studies in AD. There is evidence that treatment with acetylcholinesterase inhibitors (AChEI) leads to changes in brain physiology within the brain regions critical to AD pathology, i.e. the temporal, parietal and frontal association cortex. However, a thorough analysis combining functional and neuropsychological data has not yet been attempted, and much research is needed to validate the role of FNI as a surrogate endpoint for AD clinical trials.

Why do so many drugs for Alzheimer's disease fail in development? Time for new methods and new practices?

Alzheimer's disease (AD) drug developments and clinical trials (CT) remain vulnerable to problems that undermine research validity. Investigations of CT methods reveal how numerous factors decrease active drug-placebo group differences and increase variance, thereby reducing power to reach statistical significance for outcome measure differences in AD CTs. Such factors include, amongst many, inaccuracy, imprecision, bias, failures to follow or lack of operational protocols for applying CT methods, inter-site variance, and lack of homogeneous sampling using disorder criteria. After a review of the literature and survey of a sample of AD and Mild Cognitive Impairment (MCI) CTs, the authors question whether problems of human error preclude AD researchers from continuing their dependence on rated outcome measures for CTs. The authors propose that the realities of AD, especially a probable irreversible progression of neuropathology prior to onset of clinical symptoms or signs capable of differentiating persons at risk for AD from normal aged, require AD investigators and clinicians to privilege biomarkers and encourage their development as surrogate targets for preventive AD treatment developments, testing, and use in clinical practice.

Intrathecal corticosteroids might slow Alzheimer's disease progression

Anti-inflammatory drugs for treatment and prevention of Alzheimer's disease have to date proved disappointing, including a large study of low-dose prednisone, but higher dose steroids significantly reduced amyloid secretion in a small series of nondemented patients. In addition, there is a case report of a patient with amyloid angiopathy who had complete remission from two doses of dexamethasone, and very high dose steroids are already used for systemic amyloidosis. This paper presents the hypothesis that pulse-dosed intrathecal methylprednisolone or dexamethasone will produce detectable slowing of Alzheimer's progression, additive to that obtained with cholinesterase inhibitors and memantine. A protocol based on treatment regimens for multiple sclerosis and central nervous system lupus is outlined, to serve as a basis for formulating clinical trials. Ultimately intrathecal corticosteroids might become part of a multi-agent regimen for Alzheimer's disease and also have application for other neurodegenerative disorders.

Acetylcholinesterase inhibitor and N-methyl-D-aspartic acid receptor antagonist use among hospice enrollees with a primary diagnosis of dementia

OBJECTIVES

To describe acetylcholinesterase inhibitor (AChEI) and memantine use among persons over the age of 65 admitted to hospice with a primary diagnosis of dementia and identify patient and hospice program characteristics associated with the use of these agents.

DESIGN

Retrospective, cross-sectional study.

SETTING

Administrative database of a national hospice pharmacy provider.

PARTICIPANTS

A total of 10,065 persons with end-stage dementia admitted to one of 441 U.S. hospices in 2004.

MEASUREMENTS

The frequency of AChEI and memantine use was determined and utilized as the unit of analysis for bivariate and multivariate comparisons with patient and hospice program characteristics.

RESULTS

Twenty-one percent (2148/10,065) of patients were prescribed AChEI and/or memantine therapy at the time of hospice enrollment. Of these, 49.5% were prescribed donepezil. Odds of receiving AChEI and/or memantine therapy were less likely if the patient was female, (odds ratio [OR] 0.68, 0.62-0.76), died while enrolled in hospice (OR 0.75, 0.67-0.85), received care at home (0.80, 0.71-0.89), or had a hospice length of stay (LOS) less than 7 days (0.53, 0.45-0.62). Patients who had a LOS of at least 60 days were significantly more likely to have received such therapies (OR 1.41 [1.24-1.60] for 61-180 days and 1.33 [1.15-1.54] for over 180 days).

CONCLUSION

A notable number of hospice enrollees with a primary diagnosis of dementia were prescribed AChEI and/or NMDA receptor antagonist therapy. Studies are needed to better define the role of these agents as well as the impact of medication discontinuation in persons with end-stage dementia.

NMDA receptors in clinical neurology: excitatory times ahead

Since the N-methyl-D-aspartate receptor (NMDAR) subunits were cloned less than two decades ago, a substantial amount of research has been invested into understanding their physiological function in the healthy CNS. Research has also been directed at their pathological roles in various neurological diseases, including disorders resulting from acute excitotoxic insults (eg, ischaemic stroke, traumatic brain injury), diseases due to chronic neurodegeneration (eg, Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis), disorders arising from sensitisation of neurons (eg, epilepsy, neuropathic pain), and neurodevelopmental disorders associated with NMDAR hypofunction (eg, schizophrenia). Selective NMDAR antagonists have not produced positive results in clinical trials. However, there are other NMDAR-targeted therapies used in current practice that are effective for treating some neurological disorders. In this Review, we describe the evidence for the use of these therapies and provide an overview of drugs being investigated in clinical trials. We also discuss new NMDAR-targeted strategies in clinical neurology.

Disease-modifying approaches to Alzheimer's disease: challenges and opportunities-Lessons from donepezil therapy

The era of disease modification as a therapeutic option for Alzheimer's disease (AD) is upon us. With dozens of novel drugs in development, there is more need than ever to develop biomarkers that distinguish normal aging from AD and AD from other dementias, track changes over time as disease progresses, and respond to interventions. Future trials will need to weight biomarker outcomes equal to cognitive outcomes especially when the biomarkers are linked to specific mechanisms, such as changes to beta amyloid (Abeta) deposition or brain volume. Since the advent of donepezil as a treatment for AD, new mechanisms of action of this molecule have been discovered. In this perspective, we review trial design and discuss the use of biomarkers by using lessons learned from previous trials conducted with cholinergic therapy.

N-methyl-D-aspartate receptor antagonists have variable affect in 3-nitropropionic acid toxicity

There is accumulating evidence that excitotoxicity and oxidative stress resulting from excessive activation of glutamate (N-methyl-D-aspartate) NMDA receptors are major participants in striatal degeneration associated with 3-nitropropionic acid (3NP) administration. Although excitotoxic and oxidative mechanisms are implicated in 3NP toxicity, there are conflicting reports as to whether NMDA receptor antagonists attenuate or exacerbate the 3NP-induced neurodegeneration. In the present study, we investigated the involvement of NMDA receptors in striatal degeneration, protein oxidation and motor impairment following systemic 3NP administration. We examined whether NMDA receptor antagonists, memantine and ifenprodil, influence the neurotoxicity of 3NP. The development of striatal lesion and protein oxidation following 3NP administration is delayed by memantine but not affected by ifenprodil. However, in behavioral experiments, memantine failed to improve and ifenprodil exacerbated the motor deficits associated with 3NP toxicity. Together, these findings suggest caution in the application of NMDA receptor antagonists as a neuroprotective agent in neurodegenerative disorders associated with metabolic impairment.

Present and prospective clinical therapeutic regimens for Alzheimer's disease

Alzheimer's disease (AD) is an incurable neurodegenerative disorder that produces cognitive impairments that increase in severity as the disease progresses. The clinical symptoms are related to the presence of neuritic plaques and neurofibrillary tangles in the cerebral cortex which represent the pathophysiological hallmarks of AD. The debilitating nature of the disease can result in clinical burden for the patient, emotional strain for those that care for patients with Alzheimer's, and significant financial burden to society. The goals of current treatments, such as cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonist, are to reduce the severity or slow the progression of cognitive symptoms. Although these treatments have demonstrated modest clinical benefit, they are unable to prevent, prohibit, or reverse the underlying pathophysiology of AD. Considerable progress has been made toward the development of disease-modifying treatments. Treatments currently under development mainly target the production, aggregation, and removal of existing amyloid beta-peptide aggregates which are believed to instigate the overall development of the neuropathology. Additional strategies that target tau pathology are being studied to promote neural protection against AD pathology. The current research has continued to expand our knowledge toward the development of disease modifying Alzheimer's therapies; however, no specific treatment strategy capable of demonstrating empirical efficacy and safety has yet to emerge.

Dementia of the Alzheimer type

Dementia of the Alzheimer type is a progressive, fatal neurodegenerative condition characterized by deterioration in cognition and memory, progressive impairment in the ability to carry out activities of daily living, and a number of neuropsychiatric symptoms. This narrative review summarizes the literature regarding descriptive epidemiology, clinical course, and characteristic neuropathological changes of dementia of the Alzheimer type. Although there are no definitive imaging or laboratory tests, except for brain biopsy, for diagnosis, brief screening instruments and neuropsychiatric test batteries used to assess the disease are discussed. Insufficient evidence exists for the use of biomarkers in clinical practice for diagnosis or disease management, but promising discoveries are summarized. Optimal treatment requires both nonpharmacological and pharmacological interventions, yet none have been shown to modify the disease's clinical course. This review describes the current available options and summarizes promising new avenues for treatment. Issues related to the care of persons with dementia of the Alzheimer type, including caregiver burden, long-term care, and the proliferation of dementia special care units, are discussed. Although advances have been made, more research is needed to address the gaps in our understanding of the disease.

Blocking kinetics of memantine on NR1a/2A receptors recorded in inside-out and outside-out patches from Xenopus oocytes

Previous experiments on primary cultures of hippocampal/cortical neurones revealed that the block and unblock of N-Methyl-D-Aspartate (NMDA) receptor channels by memantine showed double exponential kinetics and that the offset kinetics following a voltage-step were much faster than following a concentration jump. There are, however, two major problems when using such cultured primary neurones for these experiments (1) the almost certain expression of heterogeneous NMDA receptor subunits which could underlie double exponential kinetics due to different potencies at receptor subtypes and (2) slow space- and concentration-clamp due to neuronal morphology which could mask even faster kinetics. Therefore, we performed similar experiments with Xenopus oocytes exclusively expressing one NMDA receptor type (NR1a/2A) at high levels which allowed recordings from membrane patches with large currents. The use of inside-out patches for voltage-step and outside-out patches in combination with a piezo driven fast application system largely negated potential space- and concentration-clamp problems. Block and unblock of the NMDA receptor by memantine after both voltage jump and concentration jumps showed triple exponential kinetics. The fast onset kinetics of NMDA receptor channel block following both concentration-clamp and voltage jumps from +70 to -70 mV were similar. In contrast, offset kinetics after a voltage-step from -70 to +70 mV were much faster than following a concentration jump at the holding potential of -70 mV. These results provide further support for the hypothesis that rapid relief of block via strong synaptic membrane depolarisation underlies the good therapeutic profile of memantine.

Memantine therapy for Alzheimer disease in real-world practice: an observational study in a large representative sample of French patients

Clinical trials have shown modest effects of memantine, an N-methyl-D aspartate receptor antagonist, in Alzheimer disease patients and memantine effectiveness in routine clinical practice needs to be established further. In 2003, memantine was recommended in France for Alzheimer disease patients with disease severity ranging from 15 to 3 on the mini-mental state examination at the first prescription. Our study aimed at describing memantine use in real-world practice in a cohort of 5283 memantine-treated patients (mean age: 80.1 y; women: 69.4%) randomly selected from the database of the national healthcare insurance, which covers 70% of the French elderly population. Mean follow-up after starting memantine prescription was 10.4 months (range: 1 to 20 mo). Patients were older and had a less severe cognitive impairment than patients included in the first controlled clinical trials. Memantine was prescribed with a cholinesterase inhibitor in 53.3% of cases. At 6 months, 26% of the patients had stopped memantine therapy (36% at 12 mo); conversely, patients who continued treatment were highly compliant. The 1-year mortality rate (12.5%) was similar for a comparative cohort of untreated demented patients and the memantine-treated ones. Approximately one-third of the memantine-treated patients did not strictly fit with the French summary of product characteristic recommendations for the first memantine prescription.

Some treatment dilemmas in rapidly developing dementia: a case report

The treatment of rapidly deteriorating dementia is always very challenging. This case report describes a 78-year-old male patient with rapidly developing dementia treated successfully with orally disintegrating olanzapine, memantine, donepezil, omega-3 and vitamin-B complex. The prevailing fatalism and treatment nihilism regarding treatment of dementia should give way to more hope and optimism. Several important treatment dillemas in rapidly developing dementia are discussed.

Factors affecting usage patterns of memantine in Alzheimer disease

Memantine is approved by the US Food and Drug Administration for the treatment of moderate to severe Alzheimer disease (AD). We investigated the frequency and variables associated with its use in mild to moderate/severe AD as defined by criteria involving the Mini-Mental Status Examination (MMSE) and Clinical Dementia Rating (CDR) scale. Consecutive possible and probable AD patients seen at our research center from November 2003 to December 2006 were included. Individuals were classified as mild dementia either by CDR=1 or MMSE >or=15, using criteria derived in part from the pivotal trials of memantine used for its approval by the Food and Drug Administration. Of 117 patients, 37% of those with mild AD by MMSE criterion (total N=94), and 38% of those with mild AD by CDR criterion (total N=86) used memantine. Logistic regression was used to simultaneously estimate the odds ratios (ORs) of the likelihood of memantine usage associated with a set of predictor variables. Lower MMSE was associated with a greater likelihood of using memantine independent of CDR [ORMMSE=7.45, 95% confidence interval (CI)=1.50-37.05]; CDR was not significantly related to memantine use. Controlling both MMSE and CDR, Whites were more likely to use memantine than African Americans (OR=6.47, 95% CI=1.25-33.39). Patients who used other antidementia medications were more likely to use memantine than those who did not (OR=3.15, 95% CI=0.995-9.97). Eight other patient characteristics were not significant predictors. Use of memantine in mild AD was common. Patterns of memantine usage are complex and deserve further study in a larger sample because of their implications for medical system cost, equitable access to care, and risk of drug interactions.

5-HT6 receptor antagonists as novel cognitive enhancing agents for Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurological condition characterized by a progressive decline in cognitive performance accompanied by behavioral and psychological syndromes, such as depression and psychosis. The neurochemical correlates of these clinical manifestations now appear to involve dysfunctions of multiple neurotransmitter pathways. Because of the extensive serotonergic denervation that has been observed in the AD brain and the important role played by serotonin (5-HT) in both cognition and behavioral control, this neurotransmitter system has become a focus of concerted research efforts to identify new treatments for AD. 5-HT exerts its diverse physiological and pharmacological effects through actions on multiple receptor subtypes. One of the newest members of this family is the 5-HT6 receptor, a subtype localized almost exclusively in the CNS, predominating in brain regions associated with cognition and behavior. With the subsequent development of selective 5-HT6 receptor antagonists, preclinical studies in rodents and primates have elucidated the function of this receptor subtype in more detail. It is increasingly clear that blockade of 5-HT6 receptors leads to an improvement of cognitive performance in a wide variety of learning and memory paradigms and also results in anxiolytic and antidepressant-like activity. These actions are largely underpinned by enhancements of cholinergic, glutamatergic, noradrenergic, and dopaminergic neurotransmission, together with learning-associated neuronal remodeling. A preliminary report that the cognitive enhancing properties of a 5-HT6 receptor antagonist (namely, SB-742457) extends into AD sufferers further highlights the therapeutic promise of this mechanistic approach.

Opioid-induced hyperalgesia in humans: molecular mechanisms and clinical considerations

Opioid-induced hyperalgesia (OIH) is most broadly defined as a state of nociceptive sensitization caused by exposure to opioids. The state is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain may actually become more sensitive to certain painful stimuli. The type of pain experienced may or may not be different from the original underlying painful condition. Although the precise molecular mechanism is not yet understood, it is generally thought to result from neuroplastic changes in the peripheral and central nervous systems that lead to sensitization of pronociceptive pathways. OIH seems to be a distinct, definable, and characteristic phenomenon that may explain loss of opioid efficacy in some cases. Clinicians should suspect expression of OIH when opioid treatment effect seems to wane in the absence of disease progression, particularly if found in the context of unexplained pain reports or diffuse allodynia unassociated with the pain as previously observed. This review highlights the important mechanistic underpinnings and clinical ramifications of OIH and discusses future research directions and the latest clinical evidence for modulation of this potentially troublesome clinical phenomenon.

Long-term course and effectiveness of combination therapy in Alzheimer disease

OBJECTIVE

To compare the real-world clinical effectiveness and long-term clinical trajectory in patients with Alzheimer disease (AD) treated with combination (COMBO) therapy consisting of cholinesterase-inhibitor (CI) plus memantine (MEM) versus CI alone versus no treatment with either.

METHODS

Three hundred eighty-two subjects with probable AD underwent serial clinical evaluations at a memory disorders unit. Cognition was assessed by the Information-Memory-Concentration subscale of the Blessed Dementia Scale (BDS) and function was assessed by the Weintraub Activities of Daily Living Scale (ADL) at 6-month intervals. One hundred forty-four subjects received standard care without CI or MEM (NO-RX), 122 received CI monotherapy, and 116 received COMBO therapy with CI plus MEM. Mean follow-up was 30 months (4.1 visits) and mean cumulative medication treatment time was 22.5 months. Rates of decline were analyzed using mixed-effects regression models, and Cohen's d effect sizes were calculated annually for years 1 to 4.

RESULTS

Covarying for baseline scores, age, education, and duration of illness, the COMBO group had significantly lower mean annualized rates of deterioration in BDS and ADL scores compared with the CI (P<0.001; Cohen's dBDS=0.10-0.34 and dADL=0.23-0.46 at 1 to 2 y) and NO-RX groups (P<0.001; Cohen's dBDS=0.56-0.73 and dADL=0.32-0.48 at 1 to 2 y). For the COMBO group, Cohen's d effect sizes increased with treatment duration. Similar comparisons significantly favored the CI over the NO-RX group on the BDS.

CONCLUSIONS

COMBO therapy slows cognitive and functional decline in AD compared with CI monotherapy and no treatment. These benefits had small-to-medium effect sizes that increased with time on treatment and were sustained for years.

Therapeutic strategies for Alzheimer's disease

Therapeutic approaches for Alzheimer's disease (AD) are guided by four disease characteristics: amyloid plaques, neurofibrillar tangles (NFT), neurodegeneration, and dementia. Amyloid plaques are composed largely of 4 kDa beta-amyloid (Abeta) peptides, with the more amyloidogenic, 42 amino acid form (Abeta42) as the primary species. Because multiple, rare mutations that cause early-onset, familial AD lead to increased production or aggregation of Abeta42, amyloid therapeutics aim to reduce the amount of toxic Abeta42 aggregates. Amyloid-based therapies include gamma-secretase inhibitors and modulators, BACE inhibitors, aggregation blockers, catabolism inducers, and anti-Abeta biologics. Tangles are composed of paired helical filaments of hyperphosphorylated tau protein. Tau-based therapeutics include kinase inhibitors, microtubule stabilizers, and catabolism inducers. Therapeutic strategies for neurodegeneration target multiple mechanisms, including excitotoxicity, mitochondrial dysfunction, oxidative damage, and inflammation or stimulation of neuronal viability. Although not disease modifying, cognition enhancers are important to treat the symptom of dementia. Strategies for cognition enhancement include cholinesterase inhibitors, and other approaches to enhance the signaling of cholinergic and glutamatergic neurons. In summary, plaques, tangles, neurodegeneration and dementia guide the development of multiple therapeutic approaches for AD and are the subject of this review.

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.

[Cross-cultural adaptation of the Disability Assessment for Dementia (DAD)]

The original version of the Disability Assessment for Dementia (DAD) was translated into Portuguese and back translated to English. The divergences of translation were identified and discussed, resulting in a version that was used in a preliminary investigation for cross-cultural adaptation. The final version was administered to 29 patients with mild to moderate probable Alzheimer's disease. The correlation coefficients of DAD were 0.929 and 0.932 for the inter-examiner and test-retest evaluations respectively. The reliability indexes were also high (Kappa 0.72 p<0.001 inter-examiners and 0.85 p<0.001 test-retest). The Brazilian version of DAD was easy to administer and had good reliability to assess the functional status of demented patients. It will contribute to the follow-up of these patients in our population. Moreover, it can be used in transcultural studies on functional abilities in dementia.

Endpoints for trials in Alzheimer's disease: a European task force consensus

Harmful consequences in health status caused by disease are referred to as outcomes, and in clinical studies the measures of these outcomes are called endpoints. A major challenge when deciding on endpoints is to represent the outcomes of interest accurately, and the accuracy of such representation is assessed through validation. Complex diseases like Alzheimer's disease have many different and interdependent outcomes. We present a consensus for endpoints to be used in clinical trials in Alzheimer's disease, agreed by a European task force under the auspices of the European Alzheimer Disease Consortium. We suggest suitable endpoints for primary and secondary prevention trials, for symptomatic and disease-modifying trials in very early, mild, and moderate Alzheimer's disease, and for trials in severe Alzheimer's disease. A clear and consensual definition of endpoints is crucial for the success of further clinical trials in the field and will allow comparison of data across studies.

Improvement in behavioural symptoms in patients with moderate to severe Alzheimer's disease by memantine: a pooled data analysis

INTRODUCTION

Behavioural disturbances are a common and distressing aspect of Alzheimer's disease (AD). This pooled analysis evaluated the specific benefits of memantine on behavioural disturbances in patients with moderate to severe AD.

METHODS

Data were pooled from six 24/28-week, randomised, placebo-controlled, double-blind studies. Of the 2,311 patients included in these studies, 1,826 patients with moderate to severe AD (MMSE <20) were included in this analysis, corresponding to the extended indication for memantine in Europe. In this subgroup, 959 patients received memantine 20 mg/day and 867 received placebo. Behavioural symptoms were rated using the Neuropsychiatric Inventory (NPI) total and single-item scores at weeks 12 and 24/28.

RESULTS

At weeks 12 and 24/28, ITT analysis demonstrated that memantine treatment produced statistically significant benefits over placebo treatment in NPI total score (p=0.001 and p=0.008), and in NPI single items: delusions (p=0.007 week 12, p=0.001 week 24/28), hallucinations (p=0.037 week 12), agitation/aggression (p=0.001 week 12, p=0.001 week 24/28), and irritability/lability (p=0.005 week 24/28), LOCF population. Analysis of the patients without symptoms at baseline indicated reduced emergence of agitation/aggression (p=0.002), delusions (p=0.047), and disinhibition (p=0.011), at week 12, and of agitation/aggression (p=0.002), irritability/lability (p=0.004), and night-time behaviour (p=0.050) at week 24/28 in those receiving memantine. OC analyses yielded similar results.

CONCLUSIONS

The data suggest that memantine is effective in treating and preventing the behavioural symptoms of moderate to severe AD. Specific persistent benefits were observed on the symptoms of delusions and agitation/aggression, which are known to be associated with rapid disease progression, increased caregiver burden, early institutionalisation, and increased costs of care.

Inflammation and aging: can endocannabinoids help?

Aging often leads to cognitive decline due to neurodegenerative process in the brain. As people live longer, there exists a growing concern linked to long-term, slowly debilitating diseases, such as Alzheimer's disease for which a cure has not yet been found. Recently, the role of neuroinflammation has attracted attention due to its slow onset, chronic nature and its possible role in the development of many different neurodegenerative diseases. In the future, treatment of chronic neuroinflammation may help counteract aspects of neurodegenerative disease. Our recent studies have focused upon the endocannabinoid system for its unique effects on the expression of neuroinflammation. The basis for the manipulation of the endocannabinoid system in the brain in combination with existing treatments for Alzheimer's disease will be discussed in this review.

Genetic aspects of Alzheimer disease

Alzheimer disease is the most common cause of dementia and represents a major public health problem. The neuropathologic findings of amyloid-beta plaques and tau containing neurofibrillary tangles represent important molecular clues to the underlying pathogenesis. Genetic factors are well recognized, but complicated. Three rare forms of autosomal-dominant early-onset familial Alzheimer disease have been identified and are associated with mutations in amyloid precursor protein, presenilin 1, and presenilin 2 genes. The more common late-onset form of Alzheimer disease is assumed to be polygenic/multifactorial. However, thus far the only clearly identified genetic risk factor for Alzheimer disease is Apo lipoprotein E. The epsilon4 allele of Apo lipoprotein E influences age at onset of Alzheimer disease, but is neither necessary nor sufficient for the disease. The search continues for the discovery of additional genetic influences.