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Memantine
Kinds of Memantine Terms modified by Memantine Selected AbstractsONCE-DAILY MEMANTINE: PHARMACOKINETIC AND CLINICAL CONSIDERATIONSJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2010AGSF, Irving H. Gomolin MDCM No abstract is available for this article. [source] Disease modifying therapy for AD?,JOURNAL OF NEUROCHEMISTRY, Issue 3 2006Todd E. Golde 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 , protein (A,) or tau accumulation. Therapies that alter A, 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 A, 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. [source] Association between amantadine and the onset of dementia in Parkinson's diseaseMOVEMENT DISORDERS, Issue 9 2006Rivka Inzelberg MD Abstract 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. © 2006 Movement Disorder Society [source] Memantine erhält Alltagsaktivitäten bei Alzheimer-PatientenPHARMAZIE IN UNSERER ZEIT (PHARMUZ), Issue 4 2003Article first published online: 1 JUL 200 Eine am 3.4.2003 im New England Journal of Medicine (NEJM 348 (2003): 1333-1341) veröffentlichte Studie bringt neue Hoffnung für alle Alzheimer-Patienten. Die Untersuchungen von Barry Reisberg et al. an 252 Patienten mit mittelschwerer bis schwerer Alzheimer-Demenz belegen die Wirksamkeit von Ebixa® (Memantine) beim Kampf gegen das Vergessen. [source] Memantine and constraint-induced aphasia therapy in chronic poststroke aphasia,ANNALS OF NEUROLOGY, Issue 5 2009Marcelo L. Berthier MD Objective We conducted a randomized, double-blind, placebo-controlled, parallel-group study of both memantine and constraint-induced aphasia therapy (CIAT) on chronic poststroke aphasia followed by an open-label extension phase. Methods Patients were randomized to memantine (20mg/day) or placebo alone during 16 weeks, followed by combined drug treatment with CIAT (weeks 16,18), drug treatment alone (weeks 18,20), and washout (weeks 20,24), and finally, an open-label extension phase of memantine (weeks 24,48). After baseline evaluations, clinical assessments were done at two end points (weeks 16 and 18), and at weeks 20, 24, and 48. Outcome measures were changes in the Western Aphasia Battery-Aphasia Quotient and the Communicative Activity Log. Results Twenty-eight patients were included, and 27 completed both treatment phases. The memantine group showed significantly better improvement on Western Aphasia Battery-Aphasia Quotient compared with the placebo group while the drug was taken (week 16, p = 0.002; week 18, p = 0.0001; week 20, p = 0.005) and at the washout assessment (p = 0.041). A significant increase in Communicative Activity Log was found in favor of memantine-CIAT relative to placebo-CIAT (week 18, p = 0.040). CIAT treatment led to significant improvement in both groups (p = 0.001), which was even greater under additional memantine treatment (p = 0.038). Beneficial effects of memantine were maintained in the long-term follow-up evaluation, and patients who switched to memantine from placebo experienced a benefit (p = 0.02). Interpretation Both memantine and CIAT alone improved aphasia severity, but best outcomes were achieved combining memantine with CIAT. Beneficial effects of memantine and CIAT persisted on long-term follow-up. Ann Neurol 2009;65:577,585 [source] Effects of the Non-Competitive NMDA Receptor Antagonist Memantine on the Volitional Consumption of Ethanol by Alcohol-Preferring RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2010Gloria E. Malpass This study examined the effects of memantine, a low-affinity, open channel NMDA antagonist, on volitional consumption of ethanol by alcohol-preferring rats and potential locomotor, sedative and hypothermic effects. Volitional consumption of ethanol in a 24-hr two-choice paradigm was determined for male Myers' high-ethanol-preferring (mHEP) rats. Effects of memantine (0.3, 1.0, 3.0 and 10.0 mg/kg, i.p., b.i.d. [twice daily] for 3 days) or vehicle on volitional consumption of ethanol, proportion of ethanol to total fluids consumed, total fluid intake and consumption of food were observed. Potential sedating and locomotor effects of memantine (10.0 mg/kg, i.p., b.i.d.) were determined using an elevated plus maze and an Auto-Track Opto-Varimex activity monitoring system. Rectal temperature was measured to determine if memantine (10.0 mg/kg, i.p.) produces a hypothermic effect. The results indicate that memantine dose-dependently decreased the amount of ethanol and proportion of ethanol to total fluids consumed daily, reaching 48% and 24%, respectively, at the highest dose. These effects did not appear to be anti-caloric. Memantine (10.0 mg/kg) partially reversed both the sedation and the reductions in locomotor activity induced by ethanol. This dose did, however, produce a small, partially reversible hypothermic effect. In conclusion, memantine may decrease ethanol consumption with fewer side effects than other NMDA receptor antagonists, such as phencyclidine (PCP), MK 801 and ketamine. [source] Inhibition of human ,7 nicotinic acetylcholine receptors by open channel blockers of N -methyl- D -aspartate receptorsBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2003Peter D Maskell Human ,7 nicotinic acetylcholine (ACh) receptors were expressed in Xenopus oocytes and the effects of the N -methyl- D -aspartate (NMDA) receptor open channel blockers memantine and cerestat on this receptor were examined using two-electrode voltage-clamp recordings and 125I- , -bungarotoxin (125I- , -bgtx) binding. Memantine and cerestat produced complete inhibition of ACh-induced inward currents with affinities similar to that reported for native NMDA receptors. Cerestat, IC50 1.7 (,1; +2) ,M, was more potent than memantine, IC50 5 (,3;+8) ,M, and the effects of both drugs were fully and rapidly reversible. Inhibition of ,7 receptor function was voltage-independent, and it occurred at concentrations far lower than those needed to inhibit (never completely) binding of 125I- , -bgtx to ,7 receptors, suggesting that the effects of memantine or cerestat are noncompetitive. These results provide evidence that human ,7 receptors are inhibited by memantine and cerestat and suggest that caution should be applied when using these compounds to study systems in which NMDA and nACh receptors co-exist. British Journal of Pharmacology (2003) 140, 1313,1319. doi:10.1038/sj.bjp.0705559 [source] Neuroprotection in emerging psychotic disordersEARLY INTERVENTION IN PSYCHIATRY, Issue 2 2007Gregor Berger Abstract Aim:, The emerging phase of psychotic disorders is pleomorphic and fluctuates in presentation. Hence, from a clinical perspective, treatment modalities are often unclear. This paper investigates the rational and potential use of neuroprotective agents in emerging psychotic disorders. Methods:, Medline databases were searched from 1966 to 2006 followed by the cross-checking of references using following keywords: neuroprotection, apoptosis, natural cell death, neurodevelopment, plasticity, neurogenesis, combined with brain and schizophrenia. Results:, Agents such as atypical antipsychotics, antidepressants, omega-3 fatty acids, modulators of glutamateric neurotransmission (e.g. ampakines, glycine, memantine), erythropoietin, N -acetylcysteine, COX-2 inhibitors or antioxidants have neuroprotective (anti-apoptotic) properties and may therefore be able to protect brain maturational processes disturbed in emerging psychotic disorders. Clinical trials suggest that atypical antipsychotics, antidepressants, omega-3 fatty acids and low-dose lithium as sole treatments were able to improve symptoms and functioning, and delay or in some cases even prevent the onset of frank psychosis. Initially these substances have been chosen because they have been used either as sole or augmentation treatments in established psychotic disorders. However, chronicity and already effective treatments may overshadow their potential clinical use in emerging (prodromal) psychosis. Conclusion:, Neuroprotection as a new treatment paradigm for at-risk mental states seems to be promising and pilot data are suggestive that more benign interventions may already be sufficient to delay or even prevent the onset of frank psychosis. A coordinated research effort will be necessary to address the question which agents should be used under which circumstances. [source] Simultaneous determination of memantine and amantadine in human plasma as fluorescein derivatives by micellar electrokinetic chromatography with laser-induced fluorescence detection and its clinical applicationELECTROPHORESIS, Issue 11 2010Hsin-Hua Yeh Abstract A nonionic surfactant MEKC method with LIF detection was developed for the simultaneous determination of memantine, an anti-Alzheimer's disease agent, and amantadine, an anti-Parkinson's disease drug, in human plasma. Before analysis, the plasma samples were pretreated by liquid,liquid extraction with ethyl acetate, and derivatized with 6-carboxyfluorescein N -hydroxysuccinimide ester. The chemical derivatization is performed with 6-carboxyfluorescein N -hydroxysuccinimide ester in ACN , 5,mM pH 9.0 borate buffer (40:60, v/v) at 35°C for 3,h. After the derivatization reaction, hydrodynamic injection (0.5,psi, 8,s) was used to introduce the derivatized solution, and the separation was performed in borate buffer (30,mM, pH 9.5) with the nonionic surfactant Brij-35® (0.07%, w/v); the separation voltage was 6,kV. The linear ranges of the method for the determination of memantine and amantadine in human plasma were over a range of 2.0,60.0,ng/mL. The detection limit was 0.5,ng/mL (S/N=3). This method was applied successfully to monitor the concentration of memantine or amantadine in patients with Alzheimer's disease or Parkinson's disease. [source] Reducing conditions significantly attenuate the neuroprotective efficacy of competitive, but not other NMDA receptor antagonists in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2000Ashley K. Pringle Abstract Inappropriate activation of NMDA receptors during a period of cerebral ischaemia is a crucial event in the pathway leading to neuronal degeneration. However, significant research has failed to deliver a clinically active NMDA receptor antagonist, and competitive NMDA antagonists are ineffective in many experimental models of ischaemia. The NMDA receptor itself has a number of modulatory sites which may affect receptor function under ischaemic conditions. Using rat organotypic hippocampal slice cultures we have investigated whether the redox modulatory site affects the neuroprotective efficacy of NMDA receptor antagonists against excitotoxicity and experimental ischaemia (OGD). NMDA toxicity was significantly enhanced in cultures pretreated with a reducing agent. The noncompetitive antagonist MK-801 and a glycine-site blocker were equally neuroprotective in both normal and reduced conditions, but there was a significant rightward shift in the dose,response curves of the competitive antagonists APV and CPP and the uncompetitive antagonist memantine. OGD produced neuronal damage predominantly in the CA1 region, which was prevented by MK-801 and memantine, but not by APV or CPP. Inclusion of an oxidizing agent during the period of OGD had no effect alone, but significantly enhanced the neuroprotective potency of the competitive antagonists. These data clearly demonstrate that chemical reduction of the redox modulatory site of the NMDA receptor decreases the ability of competitive antagonists to block NMDA receptor-mediated neuronal damage, and that the reducing conditions which occur during simulated ischaemia are sufficient to produce a similar effect. This may have important implications for the design of future neuroprotective agents. [source] The effects of the glutamate antagonist memantine on brain activation to an auditory perception taskHUMAN BRAIN MAPPING, Issue 11 2009Heidi van Wageningen Abstract Glutamate is critically involved in the regulation of cognitive functions in humans. There is, however, sparse evidence regarding how blocking glutamate action at the receptor site during a cognitive task affects brain activation. In the current study, the effects of the glutamate antagonist memantine were examined with functional magnetic resonance imaging (fMRI). Thirty-one healthy adults were scanned twice in a counter-balanced design, either in a no-drug session or after administration of memantine for 21 days. The subjects performed a simple auditory perception task with consonant-vowel stimuli. Group-level spatial independent component analysis (ICA) was used to decompose the data and to extract task-related activations. The focus was on four task-related ICA components with frontotemporal localization. The results showed that glutamate-blockage resulted in a significant enhancement in one component, with no significant effect in the other three components. The enhanced effect of memantine was in the middle temporal gyrus, superior frontal gyrus, and middle frontal gyrus. It is suggested that the results reflect effects of glutamatergic processes primarily through non- N -methyl- D -aspartate (NMDA) receptor pathways. Moreover, the results demonstrate that memantine can be used as a probe which allows for studying the effect of excitatory neurotransmission on neuronal activation. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] Effects of memantine on cognition in patients with moderate to severe Alzheimer's disease: post-hoc analyses of ADAS-cog and SIB total and single-item scores from six randomized, double-blind, placebo-controlled studiesINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2009Patrizia Mecocci Abstract Objectives The post-hoc analyses reported here evaluate the specific effects of memantine treatment on ADAS-cog single-items or SIB subscales for patients with moderate to severe AD. Methods Data from six multicentre, randomised, placebo-controlled, parallel-group, double-blind, 6-month studies were used as the basis for these post-hoc analyses. All patients with a Mini-Mental State Examination (MMSE) score of less than 20 were included. Analyses of patients with moderate AD (MMSE: 10,19), evaluated with the Alzheimer's disease Assessment Scale (ADAS-cog) and analyses of patients with moderate to severe AD (MMSE: 3,14), evaluated using the Severe Impairment Battery (SIB), were performed separately. Results The mean change from baseline showed a significant benefit of memantine treatment on both the ADAS-cog (p,<,0.01) and the SIB (p,<,0.001) total score at study end. The ADAS-cog single-item analyses showed significant benefits of memantine treatment, compared to placebo, for mean change from baseline for commands (p,<,0.001), ideational praxis (p,<,0.05), orientation (p,<,0.01), comprehension (p,<,0.05), and remembering test instructions (p,<,0.05) for observed cases (OC). The SIB subscale analyses showed significant benefits of memantine, compared to placebo, for mean change from baseline for language (p,<,0.05), memory (p,<,0.05), orientation (p,<,0.01), praxis (p,<,0.001), and visuospatial ability (p,<,0.01) for OC. Conclusion Memantine shows significant benefits on overall cognitive abilities as well as on specific key cognitive domains for patients with moderate to severe AD. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improvement in behavioural symptoms in patients with moderate to severe Alzheimer's disease by memantine: a pooled data analysisINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2008S. Gauthier Abstract 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. Copyright © 2007 John Wiley & Sons, Ltd. [source] The NMDA receptor antagonist memantine as a symptomatological and neuroprotective treatment for Alzheimer's disease: preclinical evidenceINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue S1 2003Wojciech Danysz Abstract There is increasing evidence for the involvement of glutamate-mediated neurotoxicity in the pathogenesis of Alzheimer's disease (AD). We suggest that glutamate receptors of the N-methyl-D-aspartate (NMDA) type are overactivated in a tonic rather than a phasic manner in this disorder. This continuous mild activation may lead to neuronal damage and impairment of synaptic plasticity (learning). It is likely that under such conditions Mg2+ ions, which block NMDA receptors under normal resting conditions, can no longer do so. We found that overactivation of NMDA receptors using a direct agonist or a decrease in Mg2+ concentration produced deficits in synaptic plasticity (in vivo: passive avoidance test and/or in vitro: LTP in the CA1 region). In both cases, memantine,an uncompetitive NMDA receptor antagonists with features of an ,improved' Mg2+ (voltage-dependency, kinetics, affinity),attenuated this deficit. Synaptic plasticity was restored by therapeutically-relevant concentrations of memantine (1,,M). Moreover, doses leading to similar brain/serum levels provided neuroprotection in animal models relevant for neurodegeneration in AD such as neurotoxicity produced by inflammation in the NBM or ,-amyloid injection to the hippocampus. As such, if overactivation of NMDA receptors is present in AD, memantine would be expected to improve both symptoms (cognition) and to slow down disease progression because it takes over the physiological function of magnesium. Copyright © 2003 John Wiley & Sons, Ltd. [source] Disease modifying therapy for AD?,JOURNAL OF NEUROCHEMISTRY, Issue 3 2006Todd E. Golde 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 , protein (A,) or tau accumulation. Therapies that alter A, 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 A, 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. [source] Pharmacologic Dissociation Between Impulsivity and Alcohol Drinking in High Alcohol Preferring MiceALCOHOLISM, Issue 8 2010Brandon G. Oberlin Background:, Impulsivity is genetically correlated with, and precedes, addictive behaviors and alcoholism. If impulsivity or attention is causally related to addiction, certain pharmacological manipulations of impulsivity and/or attention may affect alcohol drinking, and vice versa. The current studies were designed to explore the relationship among impulsivity, drinking, and vigilance in selectively bred High Alcohol Preferring (HAP) mice, a line that has previously demonstrated both high impulsivity and high alcohol consumption. Amphetamine, naltrexone, and memantine were tested in a delay discounting (DD) task for their effects on impulsivity and vigilance. The same drugs and doses were also assessed for effects on alcohol drinking in a 2-bottle choice test. Methods:, HAP mice were subjected to a modified version of adjusting amount DD using 0.5-second and 10-second delays to detect decreases and increases, respectively, in impulsive responding. In 2 experiments, mice were given amphetamine (0.4, 0.8, or 1.2 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) before DD testing. Another pair of studies used scheduled access, 2-bottle choice drinking to assess effects of amphetamine (0.4, 1.2, or 3.0 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) on alcohol consumption. Results:, Amphetamine dose-dependently reduced impulsivity and vigilance decrement in DD, but similar doses left alcohol drinking unaffected. Naltrexone and memantine decreased alcohol intake at doses that did not affect water drinking but had no effects on impulsivity or vigilance decrement in the DD task. Conclusions:, Contrary to our hypothesis, none of the drugs tested here, while effective on either alcohol drinking or impulsivity, decreased both behaviors. These findings suggest that the genetic association between drinking and impulsivity observed in this population is mediated by mechanisms other than those targeted by the drugs tested in these studies. [source] Antiglutamatergic Strategies for Ethanol Detoxification: Comparison With Placebo and DiazepamALCOHOLISM, Issue 4 2007Evgeny M. Krupitsky Background: Benzodiazepines are the standard pharmacotherapies for ethanol detoxification, but concerns about their abuse potential and negative effects upon the transition to alcohol abstinence drive the search for new treatments. Glutamatergic activation and glutamate receptor up-regulation contribute to ethanol dependence and withdrawal. This study compared 3 antiglutamatergic strategies for ethanol detoxification with placebo and to the benzodiazepine, diazepam: the glutamate release inhibitor, lamotrigine; the N -methyl- d -aspartate glutamate receptor antagonist, memantine; and the AMPA/kainite receptor inhibitor, topiramate. Methods: This placebo-controlled randomized single-blinded psychopharmacology trial studied male alcohol-dependent inpatients (n=127) with clinically significant alcohol withdrawal symptoms. Subjects were assigned to 1 of 5 treatments for 7 days: placebo, diazepam 10 mg TID, lamotrigine 25 mg QID, memantine 10 mg TID, or topiramate 25 mg QID. Additional diazepam was administered when the assigned medication failed to suppress withdrawal symptoms adequately. Results: All active medications significantly reduced observer-rated and self-rated withdrawal severity, dysphoric mood, and supplementary diazepam administration compared with placebo. The active medications did not differ from diazepam. Conclusions: This study provides the first systematic clinical evidence supporting the efficacy of a number of antiglutamatergic approaches for treating alcohol withdrawal symptoms. These data support the hypothesis that glutamatergic activation contributes to human alcohol withdrawal. Definitive studies of each of these medications are now needed to further evaluate their effectiveness in treating alcohol withdrawal. [source] Pharmacology and structure-activity relationships of bioactive polycyclic cage compounds: A focus on pentacycloundecane derivativesMEDICINAL RESEARCH REVIEWS, Issue 1 2005Werner J. Geldenhuys Abstract The chemistry of organic polycyclic cage compounds has intrigued medicinal chemists for over 50 years, yet little is published about their pharmacological profiles. Polycyclic cage compounds have important pharmaceutical applications, ranging from the symptomatic and proposed curative treatment of neurodegenerative diseases such as Parkinson's and Alzheimer's disease (e.g., amantadine and memantine), to use as anti-viral agents against influenza and the immunodeficiency virus (HIV). The polycyclic cage appears to be a useful scaffold to yield drugs with a wide scope of applications, and can be used also to modify and improve the pharmacokinetic and pharmacodynamic properties of drugs in current use. This review attempts to summarize the pharmacological profiles of polycyclic cage compounds with an emphasis on the lesser known pentacycloundecanes, homocubanes, and trishomocubanes. © 2004 Wiley Periodicals, Inc. [source] NMDA antagonist memantine improves levodopa-induced dyskinesias and "On-off" phenomena in Parkinson's disease,MOVEMENT DISORDERS, Issue 4 2010Sara Varanese MD No abstract is available for this article. [source] Biochemical and analytical development of the CIME cocktail for drug fate assessment in humansRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2010Orianne Videau Phenotyping based on drug metabolism activity appears to be informative regarding mechanism-based interactions during drug development. We report here the first steps of the development of the innovative CIME cocktail. This cocktail is designed not only for the major cytochrome P450, with caffeine, amodiaquine, tolbutamide, omeprazole, dextromethorphan and midazolam as substrates of CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A, respectively, but also phase II enzymes UGT 1A1/6/9 with acetaminophen, P-gp and OATP1B1 with digoxin and rosuvastatin, and renal function with memantine. An assay combining ultra-performance liquid chromatography using a 1.7,µm particle size column with tandem mass spectrometry (UPLC/MS/MS) was set up for the simultaneous quantification of the 20 substrates and metabolites after extraction from human plasma using solid-phase extraction. The method was validated in the spirit of the FDA guidelines. Mean accuracy ranged from 87.7 to 115%, the coefficient of variance (CV%) of intra- and inter-run from 1.7 to 16.4% and from 1.6 to 14.9%, respectively, and for the limit of quantification (LOQ) with ten lots of plasma, accuracy ranged from 84 to 115% and CV% precision was <16%. Short-term stability was evaluated in eluate (4,h, room temperature), plasma (24,h, room temperature), the autosampler (24,h, 4°C) and in three freeze/thaw cycles in plasma. All except three analytes were stable under these conditions. For the three others a specific process can be followed. This robust, fast and sensitive assay in human plasma provides an analytical tool for ten-probe drugs of the CIME cocktail. Clinical samples will be assayed in the near future using this new assay method. Copyright © 2010 John Wiley & Sons, Ltd. [source] Mg2+ and memantine block of rat recombinant NMDA receptors containing chimeric NR2A/2D subunits expressed in Xenopus laevis oocytesTHE JOURNAL OF PHYSIOLOGY, Issue 1 2008David C. Wrighton N -methyl- d -aspartate receptors (NMDARs) display differences in their sensitivity to the channel blockers Mg2+ and memantine that are dependent on the identity of the NR2 subunit present in the receptor,channel complex. This study used two-electrode voltage-clamp recordings from Xenopus laevis oocytes expressing recombinant NMDARs to investigate the actions of Mg2+ and memantine at the two NMDARs displaying the largest differences in sensitivity to these blockers, namely NR1/NR2A and NR1/NR2D NMDARs. In addition, NR2A/2D chimeric subunits have been employed to examine the effects of pore-forming elements and ligand-binding domains (LBD) on the potency of the block produced by each of these inhibitors. Our results show that, as previously documented, NR2D-containing NMDARs are less sensitive to voltage-dependent Mg2+ block than their NR2A-containing counterparts. The reduced sensitivity is determined by the M1M2M3 membrane-associated regions, as replacing these regions in NR2A subunits with those found in NR2D subunits results in a ,10-fold reduction in Mg2+ potency. Intriguingly, replacing the NR2A LBD with that from NR2D subunits results in a ,2-fold increase in Mg2+ potency. Moreover, when responses mediated by NR1/NR2A NMDARs are evoked by the partial agonist homoquinolinate, rather than glutamate, Mg2+ also displays an increased potency. Memantine block of glutamate-evoked currents is most potent at NR1/NR2D NMDARs, but no differences are observed in its ability to inhibit NR2A-containing or NR2A/2D chimeric NMDARs. We suggest that the potency of block of NMDARs by Mg2+ is influenced not only by pore-forming regions but also the LBD and the resulting conformational changes that occur following agonist binding. [source] Crossover trial of gabapentin and memantine as treatment for acquired nystagmusANNALS OF NEUROLOGY, Issue 5 2010Matthew J. Thurtell MBBS We conducted a masked, crossover, therapeutic trial of gabapentin (1,200mg/day) versus memantine (40mg/day) for acquired nystagmus in 10 patients (aged 28,61 years; 7 female; 3 multiple sclerosis [MS]; 6 post-stroke; 1 post-traumatic). Nystagmus was pendular in 6 patients (4 oculopalatal tremor; 2 MS) and jerk upbeat, hemi-seesaw, torsional, or upbeat-diagonal in each of the others. For the group, both drugs reduced median eye speed (p < 0.001), gabapentin by 32.8% and memantine by 27.8%, and improved visual acuity (p < 0.05). Each patient improved with 1 or both drugs. Side effects included unsteadiness with gabapentin and lethargy with memantine. Both drugs should be considered as treatment for acquired forms of nystagmus. ANN NEUROL 2010;67:676,680 [source] Memantine and constraint-induced aphasia therapy in chronic poststroke aphasia,ANNALS OF NEUROLOGY, Issue 5 2009Marcelo L. Berthier MD Objective We conducted a randomized, double-blind, placebo-controlled, parallel-group study of both memantine and constraint-induced aphasia therapy (CIAT) on chronic poststroke aphasia followed by an open-label extension phase. Methods Patients were randomized to memantine (20mg/day) or placebo alone during 16 weeks, followed by combined drug treatment with CIAT (weeks 16,18), drug treatment alone (weeks 18,20), and washout (weeks 20,24), and finally, an open-label extension phase of memantine (weeks 24,48). After baseline evaluations, clinical assessments were done at two end points (weeks 16 and 18), and at weeks 20, 24, and 48. Outcome measures were changes in the Western Aphasia Battery-Aphasia Quotient and the Communicative Activity Log. Results Twenty-eight patients were included, and 27 completed both treatment phases. The memantine group showed significantly better improvement on Western Aphasia Battery-Aphasia Quotient compared with the placebo group while the drug was taken (week 16, p = 0.002; week 18, p = 0.0001; week 20, p = 0.005) and at the washout assessment (p = 0.041). A significant increase in Communicative Activity Log was found in favor of memantine-CIAT relative to placebo-CIAT (week 18, p = 0.040). CIAT treatment led to significant improvement in both groups (p = 0.001), which was even greater under additional memantine treatment (p = 0.038). Beneficial effects of memantine were maintained in the long-term follow-up evaluation, and patients who switched to memantine from placebo experienced a benefit (p = 0.02). Interpretation Both memantine and CIAT alone improved aphasia severity, but best outcomes were achieved combining memantine with CIAT. Beneficial effects of memantine and CIAT persisted on long-term follow-up. Ann Neurol 2009;65:577,585 [source] Effects of the Non-Competitive NMDA Receptor Antagonist Memantine on the Volitional Consumption of Ethanol by Alcohol-Preferring RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2010Gloria E. Malpass This study examined the effects of memantine, a low-affinity, open channel NMDA antagonist, on volitional consumption of ethanol by alcohol-preferring rats and potential locomotor, sedative and hypothermic effects. Volitional consumption of ethanol in a 24-hr two-choice paradigm was determined for male Myers' high-ethanol-preferring (mHEP) rats. Effects of memantine (0.3, 1.0, 3.0 and 10.0 mg/kg, i.p., b.i.d. [twice daily] for 3 days) or vehicle on volitional consumption of ethanol, proportion of ethanol to total fluids consumed, total fluid intake and consumption of food were observed. Potential sedating and locomotor effects of memantine (10.0 mg/kg, i.p., b.i.d.) were determined using an elevated plus maze and an Auto-Track Opto-Varimex activity monitoring system. Rectal temperature was measured to determine if memantine (10.0 mg/kg, i.p.) produces a hypothermic effect. The results indicate that memantine dose-dependently decreased the amount of ethanol and proportion of ethanol to total fluids consumed daily, reaching 48% and 24%, respectively, at the highest dose. These effects did not appear to be anti-caloric. Memantine (10.0 mg/kg) partially reversed both the sedation and the reductions in locomotor activity induced by ethanol. This dose did, however, produce a small, partially reversible hypothermic effect. In conclusion, memantine may decrease ethanol consumption with fewer side effects than other NMDA receptor antagonists, such as phencyclidine (PCP), MK 801 and ketamine. [source] Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of pramipexole in human plasma: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 2 2009D. Vijaya Bharathi Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of pramipexole (PPX) with 500 µL human plasma using memantine as an internal standard (IS). The API-4000 was operated under multiple-reaction monitoring mode (MRM) using the electrospray ionization technique. Solid-phase extraction was used to extract PPX and IS from human plasma. The resolution of peaks was achieved with 0.01 m ammonium acetate buffer (pH 4.4):acetonitrile (30:70, v/v) on a Discovery CN column. The total chromatographic run time was 3.0 min and the elution of PPX and IS occurred at approximately 2.32 and 2.52, respectively. The MS/MS ion transitions monitored were 212.10 , 153.10 for PPX and 180.20 , 107.30 for IS. The method was proved to be accurate and precise at linearity range of 20,3540 pg/mL with a correlation coefficient (r) of ,0.999. The intra- and inter-day precision and accuracy values found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 0.25 mg PPX tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous liquid chromatographic assay of amantadine and its four related compounds in phosphate-buffered saline using 4-fluoro-7-nitro-2,1,3-benzoxadiazole as a fluorescent derivatization reagentBIOMEDICAL CHROMATOGRAPHY, Issue 5 2006Yasuhiko Higashi Abstract Simultaneous HPLC assay of 1-adamantanamine hydrochloride (amantadine) and its four related compounds [2-adamantanamine hydrochloride (2-ADA), 1-adamantanmethylamine (ADAMA), 1-(1-adamantyl)ethylamine hydrochloride (rimantadine) and 3,5-dimethyl-1-adamantanamine hydrochloride (memantine)] in phosphate-buffered saline (pH 7.4) after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed. Phosphate-buffered saline samples were mixed with borate buffer and NBD-F solution in acetonitrile at 60°C for 5 min and injected into HPLC. Five derivatives were well separated from each other. The lower limits of detection of amantadine, 2-ADA, ADAMA, rimantadine and memantine were 0.008, 0.001, 0.0008, 0.0015 and 0.01 µg/mL, respectively. The coefficients of variation for intra- and inter-day assay were less than 6.4 and 8.2%, respectively. The method presented was applied to a binding study of these compounds to human ,1 -acid glycoprotein. While affinity constants and capacities for ADAMA, rimantadine and memantine were calculated by means of Scatchard plots, those for the others were not determined. ADAMA, rimantadine and memantine were bound with different affinities and capacities. These results indicate that NBD-F is a good candidate as a fluorescent reagent to simultaneously determine amantadine and its four related compounds by HPLC after pre-column derivatization. Our method can be applied to binding studies for protein. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Treatment of Cognitive Impairment Associated with Parkinson's DiseaseBRAIN PATHOLOGY, Issue 3 2010David J. Burn FRCP Abstract Cognitive impairment and dementia associated with Parkinson's disease (PD) are common and often have devastating effects upon the patient and their family. Early cognitive impairment in PD is frequent, and the functional impact may be underestimated. Optimal management will rely upon better identification of the predominant symptoms and greater knowledge of their pathophysiological basis. The management of dementia in PD (PD-D) also has to consider the significant neuropsychiatric burden that frequently accompanies the cognitive decline, as well as fluctuations in attention. Atypical anti-psychotics have a limited role at present in treating PD-D, although new drugs are under development. The mainstay of drug management for people with PD-D is cholinesterase inhibitors, although recent trials have suggested that the N-methyl-D aspartate antagonist memantine may also have some benefit. Disease modification remains the ultimate goal for preventing the inexorable decline in PD-D, although effective interventions are still some way off. Limited benefit may, however, be possible through exercise programmes and so-called "medical foods", although randomised trials are required to confirm largely anecdotal observations. [source] Inhibition of human ,7 nicotinic acetylcholine receptors by open channel blockers of N -methyl- D -aspartate receptorsBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2003Peter D Maskell Human ,7 nicotinic acetylcholine (ACh) receptors were expressed in Xenopus oocytes and the effects of the N -methyl- D -aspartate (NMDA) receptor open channel blockers memantine and cerestat on this receptor were examined using two-electrode voltage-clamp recordings and 125I- , -bungarotoxin (125I- , -bgtx) binding. Memantine and cerestat produced complete inhibition of ACh-induced inward currents with affinities similar to that reported for native NMDA receptors. Cerestat, IC50 1.7 (,1; +2) ,M, was more potent than memantine, IC50 5 (,3;+8) ,M, and the effects of both drugs were fully and rapidly reversible. Inhibition of ,7 receptor function was voltage-independent, and it occurred at concentrations far lower than those needed to inhibit (never completely) binding of 125I- , -bgtx to ,7 receptors, suggesting that the effects of memantine or cerestat are noncompetitive. These results provide evidence that human ,7 receptors are inhibited by memantine and cerestat and suggest that caution should be applied when using these compounds to study systems in which NMDA and nACh receptors co-exist. British Journal of Pharmacology (2003) 140, 1313,1319. doi:10.1038/sj.bjp.0705559 [source] Cognitive effects of memantine in postmenopausal women at risk of dementia: a pilot studyACTA NEUROLOGICA SCANDINAVICA, Issue 3 2009T. E. Wroolie Background,,, To determine the effects of memantine on cognition in a normal population of postmenopausal women with putative risk factors for Alzheimer's disease (AD) using a built-in control for the genetic risk factor for AD (apoE-,4 status). Methods,,, A prospective, open-label, 6-month pilot medication trial with memantine and follow-up after discontinuance conducted at the Center for Neuroscience in Women's Health, Stanford University School of Medicine. Neuropsychological data were collected on 22 community-dwelling postmenopausal women (11 apoE-,4 carriers and 11 apoE-,4 non-carriers) with at least one putative risk factor for AD. Results,,, ApoE-,4 status was not a significant predictor of change in neuropsychological performance. Changes associated with memantine treatment for entire sample included significant declines in some variables associated with verbal learning and memory that improved upon medication withdrawal. A positive medication effect was noted with executive functions and possibly category fluency. Trend-level improvements were seen in motor dexterity of the non-dominant hand and maintained even after drug discontinuance. Conclusions,,, Treatment with memantine appeared to have differential effects on cognitive performance in a population of women with putative risk factors for AD. ApoE-,4 carrier status did not account for observed changes in cognition. [source] Recent clinical findings with memantine should not mean that the idea of neuroprotection in glaucoma is abandonedACTA OPHTHALMOLOGICA, Issue 4 2009Neville N. Osborne Abstract. Loss of vision in primary open-angle glaucoma (glaucoma) is caused by retinal ganglion cells dying at a seemingly steady and variable rate in different patients. Present treatments for all glaucoma patients are inadequate and a goal to rectify this is to discover appropriate drugs or chemicals (neuroprotectants) that can be taken orally to slow down retinal ganglion cell death and have negligible side-effects. It was therefore of great disappointment to learn earlier this year that the one clinical trial conducted to test the efficacy of memantine as a neuroprotectant for glaucoma was unsuccessful. In this article, I consider the mechanisms by which retinal ganglion cells may die in glaucoma and suggest that memantine may have benefited patients taking it but to a level that was difficult to detect with present methodologies. Ganglion cells are induced to die by different triggers in glaucoma, suggesting that neuroprotectants with multiple modes of actions are likely to reveal clearer results than was found for memantine. Therefore, the idea of neuroprotection in glaucoma must not be abandoned. [source] | |||||||||||||||||||||||||||||||