SEARCH · PubMed Health

Results for “Memantine”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources

PubMed2004

Memantine improves spatial learning in a transgenic mouse model of Alzheimer's disease.

Memantine, a low- to moderate-affinity uncompetitive N-methyl-D-aspartate receptor antagonist, has been shown to improve learning and memory in several pharmacological models of Alzheimer's disease (AD). In the present study, the effect of memantine on locomotor activity, social behavior, and spatial learning was assessed in a transgenic mouse model of AD. Eight-month-old male C57BL/6J mice carrying mutated human APP and PS1 genes (APP/PS1) and their nontransgenic (NT) litter mates were administered a therapeutic dose of memantine (30 mg/kg/day p.o.) for 2 to 3 weeks. At this age, APP/PS1 mice show elevated levels of beta-amyloid peptides in several brain regions. APP/PS1 mice exhibited less exploratory rearing and increased aggressive behavior compared with NT mice. In the water maze test for spatial learning, APP/PS1 mice had longer escape latencies to both hidden and visible platforms, but they did not differ from NT mice in their swimming speed. Memantine significantly improved the acquisition of the water maze in APP/PS1 mice without affecting swimming speed. Memantine did not affect either locomotor activity or aggressive behavior in either genotype. These data indicate that memantine improves hippocampus-based spatial learning in a transgenic mouse model of AD without producing nonspecific effects on locomotion/exploratory activity.

Aggression↗

PubMed2002

Modulation of blood-brain barrier dysfunction and neurological deficits during acute experimental allergic encephalomyelitis by the N-methyl-D-aspartate receptor antagonist memantine.

Previous studies by us have strongly indicated a role for the N-methyl-D-aspartate (NMDA) receptor in the pathogenesis of experimental allergic encephalomyelitis (EAE) and, moreover, the loss of blood-brain barrier (BBB) integrity implicit in the disease. The current investigation has used the NMDA receptor antagonist memantine to modify the neurological course of EAE and, in particular, prevent BBB breakdown. Memantine was administered orally either semiprophylactically, from day 7 postinoculation (PI), or therapeutically, 10 to 11 days PI. Semiprophylactic administration of drug at 60 mg/kg b.wt. significantly restored BBB integrity, reduced symptoms, and limited inflammatory lesions (p < 0.05), when assessed 12 days PI. Higher concentrations of memantine did not notably advance disease improvements observed at 60 mg/kg b.wt., and 40-mg/kg b.wt. doses only reduced histological scores (p < 0.05). Therapeutic application of memantine was found to be as effective as semiprophylactic dosing. Administration of drug at 60 mg/kg b.wt. was demonstrated as the optimum dose, significantly reducing disease, BBB permeability, and lesions (p < 0.01). Extended studies revealed that, after cessation of memantine treatment using either dosing regime, any subsequent appearance of disease was suppressed in severity and duration. We have provided further strong evidence in support of a role for the NMDA receptor in the development of EAE and, in particular, the loss of BBB function and recruitment of inflammatory cells. Moreover, memantine is therapeutically efficacious, suggesting the NMDA receptor as a viable pharmacological target for future treatment of human neurological conditions such as multiple sclerosis.

Animals↗

PubMed2004

Combination therapy in ischemic stroke: synergistic neuroprotective effects of memantine and clenbuterol.

BACKGROUND AND PURPOSE: Although excitotoxic overactivation of glutamate receptors has been identified as a major mechanism of ischemic brain damage, glutamate receptor antagonists failed in stroke trials, in most cases because of limited therapeutic windows or severe adverse effects. Therefore, we chose memantine and clenbuterol, both approved safe and efficient in their respective therapeutical categories, and examined combinations of these neuroprotectants for possible therapeutic interactions in ischemic stroke. METHODS: Combinations of the N-methyl-D-aspartate (NMDA) receptor antagonist memantine (20 mg/kg) with the beta2-adrenoceptor agonist clenbuterol (0.3 to 3 mg/kg) were tested in a mouse model of permanent focal cerebral ischemia. In addition, combinations of memantine (1 to 10 nmol/L) and clenbuterol (1 to 10 nmol/L) were examined in cultured hippocampal neurons exposed to glutamate (500 micromol/L) or staurosporine (200 nmol/L). RESULTS: The infarct size was further reduced by combination therapy as compared with effects of the respective neuroprotectants alone. Of note, in combination with memantine, the therapeutic window of clenbuterol was significantly prolonged up to 2 hours after ischemia. Experiments in postnatal cultures of rat hippocampal neurons exposed to glutamate or staurosporine confirmed that neuroprotection by combinations of memantine and clenbuterol exceeded the effects of the individual compounds. CONCLUSIONS: Combinations of memantine with clenbuterol extend the respective therapeutic window and provide synergistic cerebroprotective effects after stroke.

Adrenergic beta-Agonists↗

PubMed2004

Efficacy and safety of memantine treatment for reduction of changes associated with experimental glaucoma in monkey, II: Structural measures.

PURPOSE: To determine, using anatomic measurements, whether daily oral dosing with memantine is both safe and effective to reduce the injury associated with experimental glaucoma in primates. METHODS: Argon laser treatment of the anterior chamber angle was used to induce chronic ocular hypertension (COHT) in the right eyes of 18 macaque monkeys. Nine animals were daily orally dosed with 4 mg/kg memantine while the other nine animals received vehicle only. Measurements of intraocular pressure (IOP) from both eyes of all animals were made at regular intervals. Appearance of the optic nerve head, retinal vessels, and surrounding retina was documented with stereo fundus photographs obtained at multiple time points throughout the study. Measurements of optic nerve head topography were obtained from confocal laser scans made from animals with the highest IOPs at approximately 3, 5, and 10 months after elevation of IOP. At approximately 16 months after IOP elevation, animals were killed and histologic counts of cells in the retinal ganglion cell (RGC) layer were made. RESULTS: Histologic measurements showed that, for animals with moderate elevation of IOP, memantine treatment was associated with an enhanced survival of RGCs in the inferior retina. Measurements of optic nerve head topography showed less IOP-induced change in memantine-treated animals. This effect was seen in measurements of both the cup and the neuroretinal rim. A comparison of these same histologic and morphologic measurements in normotensive eyes from the two treatment groups showed that memantine treatment was not associated with any significant effects on these eyes. CONCLUSIONS: Histologic measurements of RGC survival as well as tomographic measurements of nerve head topography show that systemic treatment with memantine, a compound which does not lower intraocular pressure, is both safe and effective to reduce changes associated with experimental glaucoma.

Administration, Oral↗

PubMed2005

Steady-state pharmacokinetics of galantamine are not affected by addition of memantine in healthy subjects.

To evaluate the effect of multiple doses of memantine on the pharmacokinetics of galantamine and to assess the safety and tolerability of galantamine with adjunctive memantine treatment, an open-label, single-center, drug interaction study was conducted in 16 healthy adults. Subjects received an 8-mg dose of galantamine extended release once daily during week 1 and a 16-mg dose of galantamine extended release once daily during week 2. During weeks 3 and 4, they received a 16-mg dose of galantamine extended release once daily and a 10-mg dose of memantine twice daily, except on days 1 and 2 of week 3, when memantine was given as 10 mg once daily. The pharmacokinetic profile and parameters of galantamine at steady state were similar after administration of a 16-mg dose of galantamine once daily alone and after administration with a 10-mg dose of memantine twice daily. Galantamine 16 mg once daily with adjunctive memantine 10 mg twice daily was well tolerated and safe in healthy subjects.

Adult↗

PubMed2004

[Memantine: a therapeutic drug for Alzheimer's disease and the comparison with MK-801].

Memantine is agreed officially as a therapeutic drug for moderate-to-severe Alzheimer's disease (AD) in EU and USA. Memantine is a similar uncompetitive NMDA-receptor antagonist to MK-801 and phencyclidine (PCP), and it prevents nerve cell death induced by the ischemia which induces as excessive release of glutamate. These medicines act on an ion channel binding site similar to the magnesium ion binding site. However, MK-801 and PCP cause schizophrenic symptoms, so they are not being used as a therapeutic drug for AD. Memantine does not have those toxicities and does not stimulate acetylcholine release in the cerebral cortex. Although the mechanism of the difference from memantine and MK-801 has not been made clear yet, it seems that memantine is combined and released with the ion channel depending on electric potential in the same way as the magnesium ion. Basic and clinical research will clarify the control mechanism of memantine.

Alzheimer Disease↗

PubMed2006

Low doses of memantine disrupt memory in adult rats.

Memantine, a drug recently approved for treatment of Alzheimer's disease, has been characterized as a unique NMDA antagonist that confers protection against excitotoxic neurodegeneration without the serious side effects that other NMDA antagonists are known to cause. In the present study, we determined what dose of memantine is required to protect the adult rat brain against an NMDA receptor-mediated excitotoxic process and then tested that dose and a range of lower doses to determine whether the drug in this dose range is associated with significant side effects. Consistent with previous research, we found that memantine confers a neuroprotective effect beginning at an intraperitoneal dose of 20 mg/kg, a dose that we found, contrary to previous reports, produces locomotor disturbances severe enough to preclude testing for learning and memory effects. We then determined that, at intraperitoneal doses of 10 and 5 mg/kg, memantine disrupts both memory and locomotor behaviors. Rats treated with these doses performed at control-like levels in learning a hole-board task but were significantly impaired in demonstrating what they had learned when tested 24 h later. This impairment of memory retention was not state dependent in that it was demonstrable regardless of whether the rats were or were not exposed to memantine on the day of retention testing. We conclude that, in the adult rat, memantine behaves like other NMDA antagonists in that it is neuroprotective only at doses that produce intolerable side effects, including memory impairment.

Alzheimer Disease↗

PubMed2004

Failures and successes of NMDA receptor antagonists: molecular basis for the use of open-channel blockers like memantine in the treatment of acute and chronic neurologic insults.

Excitotoxicity, defined as excessive exposure to the neurotransmitter glutamate or overstimulation of its membrane receptors, has been implicated as one of the key factors contributing to neuronal injury and death in a wide range of both acute and chronic neurologic disorders. Excitotoxic cell death is due, at least in part, to excessive activation of N-methyl-D-aspartate (NMDA)-type glutamate receptors and hence excessive Ca2+ influx through the receptor's associated ion channel. Physiological NMDA receptor activity, however, is also essential for normal neuronal function; potential neuroprotective agents that block virtually all NMDA receptor activity will very likely have unacceptable clinical side effects. For this reason many NMDA receptor antagonists have disappointingly failed advanced clinical trials for a number of diseases including stroke and neurodegenerative disorders such as Huntington's disease. In contrast, studies in my laboratory were the first to show that memantine, an adamantane derivative, preferentially blocks excessive NMDA receptor activity without disrupting normal activity. Memantine does this through its action as an open-channel blocker; it enters the receptor-associated ion channel preferentially when it is excessively open, and, most importantly, its off-rate is relatively fast so that it does not substantially accumulate in the channel to interfere with normal synaptic transmission. Past clinical use for other indications has demonstrated that memantine is well tolerated, and it has recently been approved in both Europe and the USA for the treatment of dementia of the Alzheimer's type. Clinical studies of the safety and efficacy of memantine for other neurological disorders, including glaucoma and other forms of dementia, are currently underway. A series of second-generation memantine derivatives are currently in development and may prove to have even greater neuroprotective properties than does memantine. These second-generation drugs take advantage of the fact that the NMDA receptor has other modulatory sites, in addition to its ion channel, that could potentially be used for safe but effective clinical intervention.

Animals↗

PubMed2003

Memantine.

Memantine, an uncompetitive antagonist with moderate affinity for NMDA receptors, demonstrates voltage-dependency and relatively fast on/off receptor kinetics. Memantine 20 mg/day significantly slowed the rate of deterioration in outpatients with moderate to severe Alzheimer's disease in a 28-week US randomised, double-blind, placebo-controlled, multicentre study. Memantine 10 mg/day improved measures of dementia in care-dependent inpatients with Alzheimer's disease or vascular dementia in a 12-week randomised, double-blind study. Significantly more memantine than placebo recipients were responders according to Clinical Global Impression of Change scores and the Behavioural Rating Scale for Geriatric Patients Care Dependence subscale. Memantine 20 mg/day significantly improved cognition-related outcomes (cognitive subscale of the Alzheimer's Disease Assessment Scale) in patients with vascular dementia in two 28-week randomised, double-blind, placebo-controlled, multicentre trials. No statistically significant between-group difference was seen in other primary endpoints. Adverse events (incidence in memantine recipients greater than in placebo recipients) occurring in patients with moderately severe to severe dementia included diarrhoea, insomnia, dizziness, headache and hallucination.

Alzheimer Disease↗

PubMed2005

The use of memantine in dementia with Lewy bodies.

OBJECTIVE: To determine the effect of memantine in the treatment of Dementia with Lewy Bodies (DLB). BACKGROUND: While memantine has been used to successfully treat moderate-to-severe Alzheimer's disease (AD) and some non AD dementias, no reports are available regarding the effect of the drug on DLB. METHODS: We reviewed the charts of 11 subjects with DLB by McKeith Criteria that were prospectively evaluated and treated with memantine (with or without cholinesterase inhibitors (ChEIs)) for varying lengths of time. RESULTS: 9 of 11 DLB subjects on memantine were also on ChEIs. Seven of eleven were stable or improved with memantine while the remaining four worsened or responded adversely when exposed to the drug. No adverse effects on motor function were observed. CONCLUSIONS: Memantine can be used safely in patients with DLB, but its symptomatic effects may be variable.

Aged↗

PubMed2002

Memantine. Merz.

Memantine hydrochloride, an NMDA antagonist, was launched in Germany by Merz in 1989 for the treatment of dementia, an indication for which development was continuing in other markets. It is also under development by Merz, Lundbeck, Neurobiological Technologies Inc (NTI) Forest Laboratories and Suntory for the potential treatment of Alzheimer's disease (AD), AIDS-related dementia and pain in patients with neuropathy, and by Allergan for the potential treatment of ocular disease. By July 2001, a regulatory filing for neuropathic pain was expected in 2003. In February 2002, the CPMP recommended to the EU commission to approve memantine for the treatment of moderately severe-to-severe Alzheimer's disease. At this time, marketing authorization was expected late in the first half of 2002, and Lundbeck planned to launch memantine under the brand name Ebixa during the second half of 2002. Merz and Lundbeck, filed memantine for AD in the EU in September 2000 and an NDA was submitted in November of that year. The compound was in phase H trials in the US for the treatment of AIDS-related dementia and pain by August 1996 and phase III trials for glaucoma and neuroprotection by 1999. Analysts at Merrill Lynch predicted in October 2001 that Allergan would make regulatory filings in the US for memantine in glaucoma and ocular hypertension in 2005, and that Forest Laboratories would file for memantine in the US as a supplement to Alzheimer's disease data in early 2002, and for the treatment of neuropathic pain in 2003. Sales of $25 million in 2004, rising to $75 million in 2005, were predicted by Merrill Lynch for this product.

Animals↗

PubMed2003

The regulatory effect of memantine on expression and synthesis of heat shock protein 70 gene in neonatal rat models with cerebral hypoxic ischemia.

OBJECTIVE: To evaluate the neuroprotective effect of memantine, a non-competitive antagonist at the N-methyl-D-aspartate receptor, against hypoxic ischemia (HI) by exploring its regulation on the expression and synthesis of heat shock protein 70 (HSP70) gene in neonatal rat models with cerebral HI. METHODS: Memantine was intraperitoneally injected at a dose of 20 mg/kg in neonatal rat models either before (PRE group) or after (POST group) induction of HI. The expression and synthesis of the HSP70 gene and its corresponding product were determined by rapid competitive PCR and immunohistochemistry, respectively. RESULTS: There was an increase in the expression of HSP70 mRNA two hours after induction of HI, which reached its peak at 48 hours, then decreased gradually. The same expression occurred at relatively low levels in the control group. Also, HSP70 synthesis was detected as early as 2h after HI, reached its peak between 48 and 72 hours, then declined over time. After memantine administration, the expression of the gene and its synthesis of the corresponding product decreased significantly during the time intervals 24 - 72 h for the gene and 48 - 72 h for the product compared to the HI group. CONCLUSION: It was shown that HI is very sensitive to the expression of the HSP70 gene and synthesis of its corresponding product, which could be regulated by memantine. The latter may have the ability to reduce brain damage; thus decreased HSP70 mRNA expression could be a marker for HI. It is suggested that memantine can be a promising agent for neuroprotection against HI, although an overall and objective assessment of memantine is required to see if it can be used on neonates clinically later on.

Animals↗

PubMed1991

Efficacy and tolerability of memantine in patients with dementia syndrome. A double-blind, placebo controlled trial.

The efficacy and tolerability of memantine (1-amino-3,5-dimethyl-adamantane hydrochloride, Akatinol Memantine; CAS 41100-52-1) was investigated in a double-blind, randomized clinical study versus placebo in 66 patients aged between 65 and 80 years predominantly suffering from mild to moderate vascular dementia. The target variables assessed were the baseline differences of the Sandoz Clinical Assessment Geriatric scale (SCAG) and Syndrom-Kurz-Test (SKT) total scores and the total time required in the subtests of Activity of Daily Living tests (ADL). Additional parameters assessed were the physician's global impression, the Mini Mental State Evaluation (MMSE), the Tapping and Trace tests for fine motor rating and the quality in performing the ADL tests. Adverse drug effects were recorded by DOTES/TWIS. 59 of the 66 patients included in the study terminated the trial (29 in the placebo and 30 in the memantine group). For the baseline differences of the SCAG total score a statistically significant improvement was observed already after 14 days of memantine treatment as compared to placebo. After 42 days this difference was still more pronounced and highly significant. Significant improvements after 14 and 42 days of memantine treatment could also be demonstrated for the SCAG subscales cognitive disturbances, lack of drive, emotional disturbances, social behaviour and somatic disturbances. Additionally, the efficacy of the drug could be confirmed by the SKT and ADL tests. Particularly striking in the ADL tests was the considerable improvement achieved in the quality of performing the tasks under memantine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1986

Potentiation of the locomotor activity of memantine by aminophylline.

1-Amino-3,5-dimethyladamantane hydrochloride (memantine, D-145, Akatinol) and aminophylline were shown to increase the locomotor activity of mice in a dose-dependent manner; yet the effect of aminophylline took place and decreased faster than that of memantine. The ED25 for memantine was found to be 4 mg/kg; the moderate increase of locomotor activity caused by this dose of memantine was potentiated by aminophylline. The combination of both led to an over-additive immediate onset of effect and was longer lasting than that produced by memantine alone. An optimal potentiation of memantine effect was reached when it was combined with aminophylline in molar ratio of 1:2. The possible mechanism of this synergistic effect is discussed.

Amantadine↗

PubMed1982

The effect of memantine on various neurobiological processes.

Experiments are reported which show that 1,3-dimethyl-5-aminoadamantane (DMAA, D-145, memantine, Memantine) does not influence the binding capacity of a variety of tritiated ligands to rat brain membranes thus suggesting that the drug does not interact with dopamine, opioid, GABA, alpha 1- and alpha 2-adrenergic receptors, but can influence with low potency 5-HT1 receptors. Autoradiographical studies also show that memantine does not interfere with the specific uptake mechanism of various transmitter substances nor is 3H-memantine taken up by any neuronal elements. Memantine at high concentrations was shown to release 3H-monoamines which had previously been taken up by nervous tissue but the release process is independent of calcium ions and is not dose-dependent. The latter effect could be explained by CNS culture studies which show memantine to produce morphological changes in neurones and glia when present at concentrations greater than 50 mumol/l.

Amantadine↗

PubMed1995

In vivo studies on the effects of memantine on dopamine metabolism in the striatum and n. accumbens of the rat.

The action of the amantadine derivative memantine on the dopamine metabolism in the striatum and the n. accumbens of the rat was studied in vivo with different voltammetrical techniques. It was shown by differential pulse voltammetry that memantine enhanced extracellular levels of dopamine (DA) in the striatum of the anaesthetized rat, whereas an increase of 3,4 dihydroxyphenylacetic acid (DOPAC) could be observed only under freely moving conditions using square wave voltammetry. Under chloral hydrate anaesthesia the effect of memantine on extracellular DOPAC levels in the striatum and the n. accumbens was compared with MK-801, a well-known non-competitive NMDA-antagonist. Memantine did not affect striatal DOPAC concentrations under these conditions whereas MK-801 reduced the DOPAC signal. In the n. accumbens memantine enhanced the levels of extracellular DOPAC, while after MK-801 the signal was only slightly different from control. These findings suggest that in addition to its NMDA receptor antagonism, memantine affects dopaminergic transmission also by other mechanisms.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1992

Memantine has phencyclidine-like but not cocaine-like discriminative stimulus effects in rats.

It has recently been reported that the amantadine derivative, memantine, which is used in the treatment of Parkinsonism, has N-methyl-D-aspartate (NMDA) antagonist properties. In order to investigate whether the behavioural effects of memantine could also be mediated through this mechanism the drug was administered to rats trained to discriminate phencyclidine (3mg/kg) from saline. Memantine produced a dose-related (2.5-10mg/kg) substitution for phencyclidine. Neither amantadine nor cocaine substituted for phencyclidine. In rats trained to discriminate cocaine (10mg/kg) memantine did not substitute. These results show that memantine has phencyclidine-like but not cocaine-like discriminative stimulus effects indicating that the behavioural actions of memantine, like those of phencyclidine, are probably produced by a non-competitive inhibition of NMDA receptors.

Journal Article↗

PubMed2003

Memantine in moderate-to-severe Alzheimer's disease.

BACKGROUND: Overstimulation of the N-methyl-D-aspartate (NMDA) receptor by glutamate is implicated in neurodegenerative disorders. Accordingly, we investigated memantine, an NMDA antagonist, for the treatment of Alzheimer's disease. METHODS: Patients with moderate-to-severe Alzheimer's disease were randomly assigned to receive placebo or 20 mg of memantine daily for 28 weeks. The primary efficacy variables were the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) and the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory modified for severe dementia (ADCS-ADLsev). The secondary efficacy end points included the Severe Impairment Battery and other measures of cognition, function, and behavior. Treatment differences between base line and the end point were assessed. Missing observations were imputed by using the most recent previous observation (the last observation carried forward). The results were also analyzed with only the observed values included, without replacing the missing values (observed-cases analysis). RESULTS: Two hundred fifty-two patients (67 percent women; mean age, 76 years) from 32 U.S. centers were enrolled. Of these, 181 (72 percent) completed the study and were evaluated at week 28. Seventy-one patients discontinued treatment prematurely (42 taking placebo and 29 taking memantine). Patients receiving memantine had a better outcome than those receiving placebo, according to the results of the CIBIC-Plus (P=0.06 with the last observation carried forward, P=0.03 for observed cases), the ADCS-ADLsev (P=0.02 with the last observation carried forward, P=0.003 for observed cases), and the Severe Impairment Battery (P<0.001 with the last observation carried forward, P=0.002 for observed cases). Memantine was not associated with a significant frequency of adverse events. CONCLUSIONS: Antiglutamatergic treatment reduced clinical deterioration in moderate-to-severe Alzheimer's disease, a phase associated with distress for patients and burden on caregivers, for which other treatments are not available.

Activities of Daily Living↗