Amantadine and rimantadine have comparable efficacy and effectiveness in relieving or treating symptoms of influenza A in healthy adults, although rimantadine induces fewer adverse effects than amantadine. The effectiveness of both drugs in interrupting transmission is probably low. Routine use of both drugs should be discouraged and both drugs should only be used when all other measures fail.
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A paranoid schizophrenic patient developed the neuroleptic malignant syndrome after receiving three doses of fluphenazine HCl and two doses of thioridazine while he was recovering from major trauma. Treatment with diphenhydramine and benztropine mesylate was ineffective. Administration of amantadine HCl resulted in resolution of all symptoms within 24 hours. After 2 days, the amantadine was discontinued. The following day, the neuroleptic malignant syndrome appeared. Readministration of amantadine again resulted in prompt remission of symptoms.
Persistent hiccups may have a considerable impact on general health through disturbance of diet, sleep, and mood. They can cause exhaustion, malnutrition, dehydration, wound dehiscence, and even death in extreme cases. We report a complex clinical case of intractable hiccups in a patient with cancer of the pancreas and Parkinson's disease and some of the problems encountered when attempting symptom control. We also discuss a potential therapeutic response to a novel agent, amantadine, unlicensed in the treatment of hiccups.
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Two amino derivatives of (D3)-Trishomocubanes recently synthesized were evaluated for their in vivo and in vitro activities against selected viruses. Both these derivatives exhibited promising in vivo activity against Herpes simplex Type II and Influenza A2/Taiwan, comparable with aciclovir and amantadine, respectively. No in vitro activity was observed for both compounds against Herpes simplex Types I and II and Rhinovirus 1A.
Animal models in behavioral pharmacology can be evaluated based on their face, predictive and construct validity. A further level of validity may be achieved if a model is reproduced precisely across species--from laboratory animal to human--using identical conditions and manipulations to elicit identical behavioral changes. Under circumstances in which a model achieves 'homologous' validity, it should be possible to demonstrate that the same pharmacological agents produce parallel changes in the same behavior (as distinct from the clinical condition that the animal behaviors are hypothesized to model), when studied in laboratory animals and in humans. Studies have demonstrated that the disruption of sensorimotor gating of the startle reflex, measured by prepulse inhibition (PPI), in rats by dopamine agonists exhibits face, predictive and construct validity for the relative loss of PPI in schizophrenia patients. To assess the homologous validity of this model, and to expand its utility in understanding the pathophysiology of sensorimotor gating deficits and in developing novel antipsychotic agents to reverse these deficits, it will be important to study PPI across species, comparing response profiles to identical pharmacological manipulations. In the present studies, we report that PPI in rats is reduced in a dose-dependent manner by four dopamine agonists that can be administered with relative ease to humans. We also report that the PPI-disruptive effects of the clinically useful dopamine agonist pergolide are reversed by both typical and atypical antipsychotics. These studies establish a foundation for pursuing human pharmacological studies of PPI, and for extrapolating the substantial neurochemical and neurophysiological information from animal studies of PPI, towards understanding the neural basis for deficient sensorimotor gating in specific neuropsychiatric disorders.
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Amantadine, administered at a dose of 200 mg/day, antagonized the extapyramidal symptomatology induced by neuroleptic drugs in fifteen psychiatric patients. Steady-state levels were reached within 4-7 days of treatment. Individual plasma levels ranged from 200-900 ng/ml. Apparent plasma half-lives varied from 10-28.5 h with an apparent VD of 200-400 litres. A significant relationship was found between the plasma levels of amantadine and the effects on the extrapyramidal symptomatology. The data suggest a direct effect of amantadine on dopaminergic receptors.
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HBV RNA is present in virions in plasma specimens from patients with CHB. HBV RNA levels vary significantly from those of established viral markers during antiviral treatment, which highlights its potential as an independent marker in the evaluation of patients with CHB.
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The aim of the study was to evaluate the efficacy of triple antiviral therapy with interferon, ribavirin, and amantadine in comparison with interferon and ribavirin combination treatment in patients with interferon-nonresponsive chronic hepatitis C. We performed an open-label, prospective randomized controlled trial at a secondary referral center. We used a 2:1 ratio, patients received interferon, ribavirin, and amantadine, or interferon and ribavirin for 12 months, and were followed up for an additional 6 months. Ninety-four consecutive adult interferon nonresponders with chronic hepatitis C were screened. Sixty consecutive elected patients entered the study. No patients withdrew because of adverse effects. Forty patients received interferon alfa (5 megaunits on alternate days), ribavirin (800-1,000 mg daily), and amantadine (200 mg daily) for 12 months, and 20 patients received the same treatment without amantadine. At the end of follow-up, alanine transaminase (ALT) level normalization was maintained in 23 of 40 patients (57%) after triple therapy, but in 2 of 20 patients (10%) after double therapy (P <.001, RR = 2.11, 95% CI, 1.43-3.12), whereas disappearance of serum HCV RNA persisted in 19 of 40 patients (48%) and in 1 of 20 patients (5%), respectively (P <.001, RR = 1.81, 95% CI, 1.32-2.47). The safety profile was similar in the 2 groups. In conclusion, in patients with interferon-nonresponsive chronic hepatitis C, triple antiviral therapy for 1 year results in a high rate of sustained biochemical and virologic responses.
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We performed an updated meta-analysis of randomized controlled trials of combination therapy with cholinesterase inhibitors and memantine in patients with Alzheimer's disease.
In a randomised double blind parallel-group study in three centers budipine, a diphenylpiperidin derivate, was compared to amantadine with respect to efficacy and safety in the monotherapy of mild to moderate Parkinson's disease (PD). From 53 patients of either sex 27 patients were randomised to 3 x 20 mg/d budipine and 26 patients to 3 x 100 mg/d amantadine. The duration of treatment was 4 weeks in 1 center (21 patients) and 12 weeks in the other 2 centers (32 patients). Safety was measured by vital signs, ECG, adverse event recording and clinical laboratory. Both drugs caused a clinically relevant and statistically significant (p < 0.001) improvement of Parkinsonian symptoms according to the Webster-Rating-Scale (WRS) as compared to pretreatment values. With respect to the total WRS score sum there was no difference between the groups (p > 0.05; n.s.), while budipine showed a significantly (p < 0.05) better effect on the main symptom tremor after 12 weeks. During amantadine treatment more adverse events were observed than after budipine intake. Two patients left the study prematurely, one in the amantadine group due to psychiatric adverse events and one in the budipine group because of insufficient efficacy.
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The mean age was 57.4 years (range: 47-72) and the mean disease duration was 30.8 months (range: 11-79). The ataxia severity significantly decreased after intravenous amantadine therapy from 42.5 to 37.3 (p < 0.001). The mean patient global impression scale for improvement was 2.9 and there were no side effects of intravenous amantadine treatment observed. When we assessed responders, the duration of intravenous amantadine effect was more than 1 month in 4 subjects of 7 responders.
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NB is short auxiliary protein with ca. 100 amino acids, encoded in the viral genome of influenza B. It is believed to be similar to M2 from influenza A and Vpu from HIV-1 in that it demonstrates ion channel activity. Channels formed by the protein can be blocked by amantadine. We have synthesized the putative transmembrane segment of NB (IRG S20 IIITICVSL I30 VILIVFGCI A40 KIFI (NB, Lee)). Reconstituted in a lipid bilayer, the peptide shows channel activity. The addition of amantadine leads to dose-dependent loss of channel activity. Channel blocking is reversible. Channel behaviour of the peptide in the presence of amantadine is in accordance with findings for the intact channel. Thus, the synthetic transmembrane peptide captures the ion channel activity of the intact NB protein.
Randomised controlled trials (RCTs) or quasi-RCTs comparing amantadine and/or rimantadine with no intervention, placebo, other antivirals or different doses or schedules of amantadine or rimantadine in children and the elderly with influenza A.
In 13 of 27 cases of persistent dyskinesia, treatment with amantadine, in an average dose of 300 mg, brought good to moderate improvement. In 14 patients who showed no response whatever, further treatment, with bromocriptine in doses raised gradually to a final daily dosage of 15 mg, was effective in four cases, though the improvement was generally only moderate. In more than 50 percent of the cases of initial tremor induced by lithium therapy, oxprenolol in daily doses of 160--240 mg produced good effects and moderate improvement was noted in a few further cases. In a series of 20 patients with initial tremor due to neuroleptic therapy, on the other hand, the same treatment proved unsuccessful in the majority of cases. This is the converse of the experience gained with the classical antiparkinson agents, which have proved more effective against tremor induced by neuroleptics than against lithium-induced tremor.
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We searched the Cochrane Acute Respiratory Infections Group Specialised Trials Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and the GlaxoSmithKline Clinical Trials Register, generally from inception through to December 2002. We also screened the references of retrieved articles and scrutinised relevant web sites. We also screened references of retrieved articles and other systematic reviews, scrutinised web sites of European and US regulatory bodies, and contacted manufacturers and authors.
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An altered glutamatergic transmission within the central nervous system is supposed to be involved in the generation and propagation of neuropathic pain. Results from experimental studies with animal models of neuropathic pain demonstrate that glutamate antagonists have a positive effect on various parameters. Clinical studies with the NMDA-receptor antagonists ketamine, amantadine, memantine and dextromethorphan and with the antiepileptics gabapentin and lamotrigine, which reduce presynaptic release of glutamate,have been performed. They have shown that most of these substances can reduce neuropathic pain. Important side effects of the NMDA receptor antagonists are hallucination and agitation, whereas tiredness and dizziness are the ones of the antiepileptics. Till now, glutamate antagonists are not drugs of first choice for the treatment of neuropathic pain. However, they are an effective alternative in case the established drugs are not helpful or are not tolerated well.
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This retrospective multicentric study conducted in seven Italian Ambulatory Centers for Dementia assessed the efficacy and safety of memantine 20 mg/day administered for 6 months in addition to an AChEI in AD patients with worsened cognitive functions and behavioral disorders.
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Schizophrenia is comprised of several debilitating symptoms. Antipsychotics offer an effective treatment for positive symptoms, while the negative signs and cognitive deficits are usually treatment-resistant. It was suggested that glutamate dysregulation may be involved in the neuropathology of schizophrenia, mainly through NMDA dysfunction. We hypothesized that addition of memantine, a weak non-selective NMDA receptor antagonist approved for dementia, to antipsychotics would improve the clinical status of un-remitted schizophrenia patients, notably the negative signs and cognitive deficits.
Chronic ocular hypertension was associated with a reduction in the amplitude of components of the multifocal ERG response and visually-evoked cortical potential. Memantine-treated animals suffered less amplitude reduction for these measures than did vehicle-treated animals, though this treatment effect on the ERG measures was observed only at the early time points (3 and 5 months post IOP elevation). Memantine treatment was not associated with an effect on either the kinetics or amplitude of ERG or VECP response measures obtained from the normotensive eyes.
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Alzheimer's disease (AD) is an age-dependent neurodegenerative disorder and the most common cause of dementia. The early stages of AD are characterized by short-term memory loss. Once the disease progresses, patients experience difficulties in sense of direction, oral communication, calculation, ability to learn, and cognitive thinking. The median duration of the disease is 10 years. The pathology is characterized by deposition of amyloid beta peptide (so-called senile plaques) and tau protein in the form of neurofibrillary tangles. Currently, two classes of drugs are licensed by the European Medicines Agency for the treatment of AD, ie, acetylcholinesterase inhibitors for mild to moderate AD, and memantine, an N-methyl-D-aspartate receptor antagonist, for moderate and severe AD. Treatment with acetylcholinesterase inhibitors or memantine aims at slowing progression and controlling symptoms, whereas drugs under development are intended to modify the pathologic steps leading to AD. Herein, we review the clinical features, pharmacologic properties, and cost-effectiveness of the available acetylcholinesterase inhibitors and memantine, and focus on disease-modifying drugs aiming to interfere with the amyloid beta peptide, including vaccination, passive immunization, and tau deposition.
We found 19 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Alzheimer's dementia represents organ failure of the brain. It denotes a clinical milestone that is the result of a pathological process, Alzheimer's disease (AD), which over 1 or more decades has wrought insidious destruction, and finally overwhelmed the brain's capacities to compensate. It is incurable, progressive, and follows an individual pace and course. AD is particularly demanding and devastating to family and caregivers, and patients, all of whom suffer psychologically and emotionally. The cholinesterase inhibitors (ChEIs) donepezil, galantamine, and rivastigmine and the N-methyl- D-aspartate receptor antagonist memantine are approved by the US Food and Drug Administration for AD; they are often used in combination once the disease reaches moderate stages. The relatively good safety profile of these medications, along with their efficacy in alleviating symptoms, is supported by several level-I evidence-grade, short-term, randomized, placebo-controlled trials (RCTs). However, these studies are of limited value in assessing the real-world clinical and economic impact of AD therapies. Long-term, observational studies can provide complementary information to results from short-term clinical trials and more accurately assess practical long-term benefits, risks, costs, and effects on clinically meaningful end points. There is now accumulating and convergent evidence from short- and long-term RCTs, longer-term open-label extensions of RCTs, and long-term observational studies that ChEIs and memantine reduce decline in cognition and daily function, and delay nursing home placement. Optimal care in AD is multifactorial; it includes early diagnosis and multidisciplinary care with educational and nonpharmacological interventions, while ensuring safety, treating comorbidities, caring for caregivers, and appropriate initiation and maintenance of combination therapy.
Idiopathic spasmodic torticollis (IST) is discussed from the perspective of definition and description, clinical presentation, and modes of treatment including a new, innovative, surgical approach. The role of the physician and the neurosurgical nurse in the management of idiopathic spasmodic torticollis is considered.
The potential of most N-methyl-D-aspartate antagonists as neuroprotectants is limited by side effects. We previously reported that memantine is an open-channel N-methyl-D-aspartate blocker with a faster off-rate than many uncompetitive N-methyl-D-aspartate antagonists such as dizocilpine maleate. This parameter correlated with memantine's known clinical tolerability in humans with Parkinson's disease. Memantine is the only N-methyl-D-aspartate antagonist that has been used clinically for excitotoxic disorders at neuroprotective doses. Therefore, we wanted to investigate further the basis of its clinical efficacy, safety, and tolerability. Here we show for the first time for any clinically-tolerated N-methyl-D-aspartate antagonist that memantine significantly reduces infarct size when administered up to 2 h after induction of hypoxia/ischemia in immature and adult rats. We found that at neuroprotective concentrations memantine results in few adverse side effects. Compared to dizocilpine maleate, memantine displayed virtually no effects on Morris water maze performance or on neuronal vacuolation. At concentrations similar to those in brain following clinical administration, memantine (6-10 microM) did not attenuate long-term potentiation in hippocampal slices and substantially spared the N-methyl-D-aspartate component of excitatory postsynaptic currents, while dizocilpine maleate (6-10 microM) or D-2-amino-5-phosphovalerate (50 microM) completely blocked these phenomena. We suggest that the favorable kinetics of memantine interaction with N-methyl-D-aspartate channels may be partly responsible for its high index of therapeutic safety, and make memantine a candidate drug for use in many N-methyl-D-aspartate receptor-mediated human CNS disorders.
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Postmortem fluid and tissue concentrations of memantine (Namenda), a drug recently approved for the treatment of Alzheimer's Disease by the FDA, are reported in a suspicious death. In addition, memantine concentrations considered to be incidental findings in three other cases are included to aid in the interpretation in future toxicological investigations. Memantine was extracted from biological samples by a standard liquid-liquid basic drug method followed by analysis utilizing a gas chromatograph-mass spectrometer operated in SIM mode. Blood concentrations ranged from 0.03 to 1.8 mg/L, and the liver concentration was 6.1 mg/kg.
Levodopa-induced dyskinesias (LID) are amongst the most disabling side-effects of levodopa therapy for Parkinson's disease (PD). It has been suggested that that N-Methyl-D-Aspartate (NMDA)-receptor antagonist may reduce peak-dose dyskinesia in PD patients and may lead to motor improvement. In this study, we compared the efficacy of NMDA receptor antagonists versus placebo in the treatment of LID in PD through a meta-analysis of controlled trials.
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Over the last six years, eight new substances for the treatment of idiopathic parkinsonism (IP) have been approved for use: four oral and one parenteral dopamine agonist (apomorphine), two COMT-inhibitors and budipine. The old drug amantadine has experienced a renaissance in the treatment of a complication occurring during long-term treatment of IP, namely levodopa-induced dyskinesia. Deep brain stimulation with programmable pulse generators and stereotactically implanted electrodes are increasingly being used in patients with severe on-off phases and levodopa dyskinesia. The treatment of Parkinson's disease unresponsive to dopaminergic substances and that associated with dementia remains problematical. In combinations of parkinsonism and dementia, the cholinesterase inhibitors are being used in particular for Lewy body dementia.