Memantine elicits spinal blockades of motor function,proprioception, and nociception in rats

Although memantine blocks sodium currents and produces local skin anesthesia, spinal anesthesia with memantine is unknown. The purpose of the study was to evaluate the local anesthetic effect of memantine in spinal anesthesia and its comparison with a widely used local anesthetic lidocaine. After intrathecally injecting the rats with five doses of each drug, the dose—response curves of memantine and lidocaine were constructed. The potencies of the drugs and durations of spinal anesthetic effects on motor function, proprioception, and nociception were compared with those of lidocaine. We showed that memantine produced dose‐dependent spinal blockades in motor function, proprioception, and nociception. On a 50% effective dose (ED₅₀) basis, the rank of potency was lidocaine greater than memantine (P < 0.05 for the differences). At the equipotent doses (ED₂₅, ED₅₀, ED₇₅), the block duration produced by memantine was longer than that produced by lidocaine (P < 0.05 for the differences). Memantine, but not lidocaine, displayed more sensory/nociceptive block than motor block. The preclinical data demonstrated that memantine is less potent than lidocaine, whereas memantine produces longer duration of spinal anesthesia than lidocaine. Memantine shows a more sensory‐selective action over motor blockade.     

Memantine combined with environmental enrichment improves spatial memory and alleviates Alzheimer’s disease-like pathology in senescence-accelerated prone-8(SAMP8) mice

Memantine is a N-methyl-D-aspartate(NMDA) receptor antagonist approved for the treatment of moderate to severe Alzheimer’s disease(AD).Environmental enrichment(EE) has shown significant beneficial effects on functional improvement in AD.In this study,we sought to determine whether combining these two distinct therapies would yield greater benefit than either drug used alone.We investigated the effect of memantine combined with EE on spatial learning and memory and AD-like pathology in a widely used AD model,the senescence-accelerated prone mice(SAMP8).The SAMP8 mice were randomly assigned to enriched housing(EH) or standard housing(SH),where either memantine(20 mg/kg) or saline was given by gastric lavage once daily continuously for eight weeks.Our results showed that,when provided separately,memantine and EE significantly improved spatial learning and memory by shortening escape latencies and increasing the frequency of entrance into the target quadrant.When combined,memantine and EE showed additive effect on learning and memory as evidenced by significant shorter escape latencies and higher frequency of target entrance than either drug alone.Consistent with the behavior results,pathological studies showed that both memantine and EE significantly reduced hippocampal CA1 neurofibrilliary tangles(NFTs) as well as amyloid beta precursor protein(APP) levels.Combining both therapies synergistically lessened NFTs and APP expression compared to either drug alone in SAMP8 mice,indicating that the combination of memantine with EE could offer a novel and efficient therapeutic strategy for the treatment of AD.     

Persistence and Adherence With Dementia Pharmacotherapy: Relevance of Patient,Provider, and System Factors

This paper provides a comprehensive review of studies examining adherence and (or) persistence with dementia pharmacotherapy during the past decade, including a summary of the key patient-, drug-, system-, and provider-level factors associated with these measures. Estimates of adherence and 1-year persistence to these drugs have ranged from 34% to 94% and 35% to 60%, respectively. Though many studies reported nonsignificant associations, there are data suggesting that patient age, sex, ethnoracial background, socioeconomic status, and region-specific reimbursement criteria, as well as the extent and quality of interactions among patients, caregivers, and providers, may influence persistence with pharmacotherapy. As many studies relied on administrative data, limited information was available regarding the relevance of patient’s cognitive and functional status or the importance of caregiver involvement or assistive devices to adherence or persistence.     

美金刚与血管性痴呆

兴奋性氨基酸毒性是血管性痴呆的发病机制之一,谷氨酸是脑内主要的兴奋性神经递质.美金刚是一种中等亲和力、非竞争性、电压依赖性N-甲基-D-天冬氨酸(NMDA)受体阻滞剂,能够阻断NMDA受体介导的胞内Ca2+超载,避免兴奋性毒性,可用于血管性痴呆的治疗.     

美金刚联合多巴丝肼对帕金森病痴呆预后效果、安全性分析

目的：探究美金刚联合多巴丝肼对帕金森病痴呆预后效果、安全性分析。方法：选择2018年1月-12月某院收治的帕金森痴呆患者200例,按照随机数字表法分为参照组与研究组,各100例。参照组行多巴丝肼治疗,研究组在参照组基础上加用美金刚。治疗结束后对比2组患者的日常生活能力、智力、认知能力、血清免疫指标、不良反应。结果：治疗结束后,研究组（39.16±4.24）患者日常生活能力评分显著高于参照组（34.56±4.67）（t=4.382 8,P=0.041 7）。停药后2个月,研究组（39.68±3.76）患者日常生活能力评分显著高于参照组（34.31±3.45）（t=4.168 4,P=0.040 3）。对认知能力评分,停药后研究组患者评分（13.89±2.41）显著高于参照组（11.76±2.54）（t=4.785 7,P=0.048 5）,停药2个月后,研究组（13.56±2.37）显著高于参照组（11.87±2.42）（t=5.765 6,P=0.047 3）。同样,IgG水平、IgM水平,研究组均改善优于参照组,具有显著差异（P<0.05）。对比2组患者停药后不良反应,研究组不良反应发生率低于参照组具有显著性差异（P<0.05）。结论：对帕金森患者实施美金刚联合多巴丝肼治疗,有效改善痴呆症状,不良反应少,安全性高,治疗效果显著。     

Memantine can relieve the neuronal impairment caused by neurotropic virus infection

Neurotropic viruses, such as the rabies virus (RABV) and Japanese encephalitis virus (JEV), induce neuronal dysfunction and complication, causing neuronal damage. Currently, there are still no effective clinical treatments for neuronal injury caused by neurotropic viruses. Memantine, a drug capable of passing through the blood-brain barrier, noncompetitively and reversibly binds to n -methyl- d -aspartic acid (NMDA) receptors. Memantine is used to treat Alzheimer's disease by blocking the activation of extra axonal ion channels, thus preventing neuronal degeneration by inhibiting the abnormal cytosolic Ca ²⁺ increase. To explore whether memantine can alleviate neurological disturbances caused by RABV and JEV, the following experiments were carried out: (1) for primary neurons cultured in vitro infected with RABV, the addition of memantine showed neuroprotection. (2) In the RABV challenge experiments, memantine had limited therapeutic effect, mildly extending the survival time of mice. In contrast, memantine significantly prolonged the survival time of mice infected with JEV, by reducing the intravascular cuff and inflammatory cell infiltration in mice. Furthermore, memantine decreases the amount of JEV virus in mice brain.     

A pharmacoeconomic evaluation of cholinesterase inhibitors and memantine for the treatment of Alzheimer’s disease

Introduction: Alzheimer’s disease (AD) results in progressively worsening cognitive decline, leading to loss of functional ability, behavior/mood disturbances, institutionalization, and death. Current pharmaceutical therapies only treat the symptoms of cognitive decline yet can be expensive for payers.

Areas covered: The authors undertook a systematic review of economic evaluations of pharmaceutical therapies for AD. The literature search encompassed English-language studies indexed in PubMed (Medline), Cochrane Library Current, and Web of Science. The search included articles published between 1 January 1995 and 10 February 2018. The literature suggested AD medications generally dominated comparator treatments (e.g. placebo).

Expert opinion: The authors noted several limitations of the included economic evaluations. These limitations suggest the results of the economic evaluations should be interpreted with caution. Many economic models were not transparent with respect to sources of probabilities and cost data, and data collected in certain jurisdictions were applied to other jurisdictions without considering the validity of such applications. Measuring health utilities in cognitively impaired populations raises questions about the validity of quality-adjusted life years, but this issue was unaddressed in the included studies. Most included studies were sponsored by industry and the results tended to overwhelmingly support the manufacturer’s product.