Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new reminyl research articles will be listed here shortly after becoming available to us.
Medical research on reminyl
CNS Drugs. 2010 Apr 1; 24(4): 303-17
Ribeiz SR, Bassitt DP, Arrais JA, Avila R, Steffens DC, Bottino CM
Cognitive deficits have been described in patients with schizophrenia from the first descriptions of dementia praecox to current concepts of cognitive dysmetria. Nevertheless, little is known about how to deal with them. In Alzheimer disease, cholinergic deficit is found and cholinesterase inhibitors have been used to delay the progression of memory and cognitive dysfunction. Several lines of evidence suggest that the cholinergic system may be disrupted in schizophrenia. To evaluate cognitive and clinical effects of adjunctive cholinesterase inhibitors in patients with schizophrenia and schizoaffective disorder. We conducted a literature search on PubMed and EMBASE (up to December 2008) for articles that investigated adjunctive cholinesterase inhibitors in patients with schizophrenia. The terms 'schizophrenia', 'acetylcholinesterase inhibitors', 'rivastigmine', 'donepezil', 'galantamine' and 'cognitive deficit' were searched with restriction for English language and without a year limit. All articles that presented original data from randomized, double-blind, placebo-controlled trials with donepezil, rivastigmine or galantamine in patients with schizophrenia or schizoaffective disorder were included in the meta-analysis. Studies were excluded for the following reasons: (i) case study/letter/correspondence/review; (ii) animal study; (iii) molecular/genetic investigation; and (iv) inclusion of patients with schizophrenia and co-morbid dementia. Few appropriate data for meta-analysis were found because of the large heterogeneity of the assessment instruments used. Nevertheless, effects of cholinesterase inhibitors in some cognitive domains (executive function, memory and language), psychopathology (using the Positive and Negative Syndrome Scale) and extrapyramidal symptoms could be analysed. Six open-label and 24 double-blind studies were found. In five open-label studies there was an improvement in memory, attention and executive functions. Thirteen double-blind studies (four with rivastigmine, six with donepezil and three with galantamine) contributed to the meta-analysis. Significant improvement was found in this analysis for memory and the Trail Making test part A. The reviewed studies suggest that specific cognitive deficits (memory, and the motor speed and attention part of executive function) of patients with schizophrenia and schizoaffective disorder are responsive to rivastigmine, donepezil and galantamine as adjunctive therapy. Confirmatory studies are needed to determine the clinical utility of this treatment strategy.
Int J Neuropsychopharmacol. 2010 Mar 11; 1-12
Noda Y, Mouri A, Ando Y, Waki Y, Yamada SN, Yoshimi A, Yamada K, Ozaki N, Wang D, Nabeshima T
Galantamine, a drug used to treat Alzheimer's disease, inhibits acetylcholinesterase (AChE) and allosterically modulates nicotinic acetylcholine receptors (nAChRs) resulting in stimulation of catecholamine neurotransmission. In this study, we investigated whether galantamine exerts cognitive-improving effects through the allosteric modulation of nAChRs in an animal model of methamphetamine (Meth) psychosis. The mice treated with Meth (1 mg/kg.d) for 7 d showed memory impairment in a novel object recognition test. Galantamine (3 mg/kg) ameliorated the memory impairment, and it increased the extracellular dopamine release in the prefrontal cortex (PFC) of Meth-treated mice. Donepezil, an AChE inhibitor (1 mg/kg) increased the extracellular ACh release in the PFC, whereas it had no effect on the memory impairment in Meth-treated mice. The nAChR antagonist, mecamylamine, and dopamine D1 receptor antagonist, SCH 23390, blocked the ameliorating effect of galantamine on Meth-induced memory impairment, whereas the muscarinic AChR antagonist, scopolamine, had no effect. The effects of galantamine on extracellular dopamine release were also antagonized by mecamylamine. Galantamine attenuated the defect of the novelty-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2). The ameliorating effect of galantamine on recognition memory in Meth-treated mice was negated by microinjection of an ERK inhibitor, PD98059, into the PFC. These results suggest that the ameliorating effect of galantamine on Meth-induced memory impairment is associated with indirect activation of dopamine D1 receptor-ERK1/2 following augmentation with dopaminergic neurotransmission in the PFC through the allosteric activation of nAChRs. Galantamine could be a useful therapeutic agent for treating cognitive deficits in schizophrenia/Meth psychosis, as well as Alzheimer's disease.
Adv Exp Med Biol. 2010; 669: 103-7
Brundage CM, Nelson CA, Taylor BE
Juvenile bullfrogs previously identified as highly sensitive to acute nicotine, demonstrated normal neuroventilation following 3 wk of chronic nicotine exposure. Acute bath application of 1 muM galantamine, an acetylcholinesterase inhibitor, significantly attenuated both bullfrog normocapnic neuroventilation and response to hypercapnia in a fashion similar to that of acute nicotine. This would suggest that the developmental increase in nicotine sensitivity does not enhance vulnerability to chronic exposure, and that acute nicotine acts via endogenous acetylcholine pathways to depress neuroventilation and hypercapnic drive.
Entering and Exiting the Medicare Part D Coverage Gap: Role of Comorbidities and Demographics.
J Gen Intern Med. 2010 Mar 9;
Ettner SL, Steers N, Duru OK, Turk N, Quiter E, Schmittdiel J, Mangione CM
BACKGROUND: Some Medicare Part D enrollees whose drug expenditures exceed a threshold enter a coverage gap with full cost-sharing, increasing their risk for reduced adherence and adverse outcomes. OBJECTIVE: To examine comorbidities and demographic characteristics associated with gap entry and exit. DESIGN: We linked 2005-2006 pharmacy, outpatient, and inpatient claims to enrollment and Census data. We used logistic regression to estimate associations of 2006 gap entry and exit with 2005 medical comorbidities, demographics, and Census block characteristics. We expressed all results as predicted percentages. PATIENTS: 287,713 patients without gap coverage, continuously enrolled in a Medicare Advantage Part D (MAPD) plan serving eight states. Patients who received a low-income subsidy, could not be geocoded, or had no 2006 drug fills were excluded. RESULTS: Of enrollees, 15.9% entered the gap, 2.6% within the first 180 days; among gap enterers, only 6.7% exited again. Gap entry was significantly associated with female gender and all comorbidities, particularly dementia (39.5% gap entry rate) and diabetes (28.0%). Among dementia patients entering the gap, anti-dementia drugs (donepezil, memantine, rivastigmine, and galantamine) and atypical antipsychotic medications (risperidone, quetiapine, and olanzapine) together accounted for 40% of pre-gap expenditures. Among diabetic patients, rosiglitazone accounted for 7.2% of pre-gap expenditures. Having dementia was associated with twice the risk of gap exit. CONCLUSIONS: Certain chronically ill MAPD enrollees are at high risk of gap entry and exposure to unsubsidized medication costs. Clinically vulnerable populations should be counseled on how to best manage costs through drug substitution or discontinuation of specific, non-essential medications.
Curr Alzheimer Res. 2010 Feb 1; 7(1): 67-73
Darreh-Shori T, Soininen H
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline associated with a deficit in cholinergic function. Inhibitors of acetylcholinesterase (AChE) and/or butyrylcholinesterase (BuChE), such as donepezil, galantamine or rivastigmine, are widely prescribed as symptomatic treatments for AD. These agents exhibit a wide variation in their pharmacological properties. Here we review clinical data from 1998 to 2009 investigating the effect of different cholinesterase inhibitor treatments on the levels and activities of cholinesterases in the cerebrospinal fluid (CSF) of AD patients. These studies suggest that treatment with rapidly-reversible cholinesterase inhibitors (e.g. donepezil, galantamine, tacrine) are associated with marked and significant upregulation of AChE activities and protein levels in the CSF of AD patients. In contrast, pseudo-irreversible cholinesterase inhibition (e.g. rivastigmine) is associated with a significant decrease in both CSF AChE and BuChE activities, with no upregulation of CSF protein levels. Additionally, donepezil is associated with a decrease in the level of the AChE-R isoform relative to the synaptic AChE-S isoform, whereas rivastigmine seems to increase this ratio. These findings suggest that these agents exert different effects on CSF cholinesterases. The clinical effects of these pharmacological differences are yet to be fully established.
J Pharmacol Exp Ther. 2010 Mar 1;
Giorgetti M, Gibbons JA, Bernales S, Alfaro IE, Drieu La Rochelle C, Cremers T, Altar CA, Wronski R, Hutter-Paier B, Protter AA
Dimebon (latrepirdine, dimebolin) treatment enhances cognition in patients with Alzheimer's or Huntington disease. Although dimebon was originally thought to improve cognition and memory through inhibition of acetylcholinesterase (AChE) and the N-methyl-D-aspartate (NMDA) receptor, the low in vitro affinity for these targets suggests that these mechanisms may not contribute to its clinical effects. To test this hypothesis, we assessed whether dimebon enhances cognition in rats and if such an action is related to either mechanism, or additional candidate mechanisms. Acute oral administration of dimebon to rats (0.05, 0.5, and 5 mg/kg) enhanced cognition in a novel object recognition task, and produced dimebon brain concentrations of 1.7 +/- 0.43 nM, 14 +/- 5.1 nM, and 172 +/- 94 nM, respectively. At these concentrations, dimebon did not alter the activity of recombinant human or rat brain AChE. Unlike the AChE inhibitors donepezil and galantamine, dimebon did not change acetylcholine levels in the hippocampus or prefrontal cortex of freely-moving rats. Dimebon displays affinity for the NMDA-receptor (K(i)=105+/-18muM) that is considerably higher than brain concentrations associated with cognition enhancement in the novel object recognition task, and 200-fold weaker than that of memantine (K(i)=0.54+/-0.05muM). Dimebon did not block NMDA-induced calcium influx in primary neuronal cells (IC(50) >50 microM) consistent with a lack of significant effect on this pathway. The cognition-enhancing effects of dimebon are unlikely to be mediated by AChE inhibition or NMDA receptor antagonism, and its mechanism of action appears to be distinct from currently approved medications for Alzheimer's disease.
Pharmacol Res. 2010 Mar 1;
Repantis D, Laisney O, Heuser I
The term neuroenhancement refers to improvement in the cognitive, emotional and motivational functions of healthy individuals through, inter alia, the use of drugs. Of known interventions, psychopharmacology provides readily available options, such as the anti-dementia drugs, e.g. acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine) and memantine. Based on a systematic review we found that expectations about the potential of these drugs exceed their actual effects, as has been demonstrated in randomised controlled trials. Both single and repeated dose trials were included in the systematic review, however repeated dose trials have only been conducted for donepezil. In six small trials lasting 14-42 days, the following results emerged: donepezil improved the retention of training on complex aviation tasks and verbal memory for semantically processed words. In one study episodic memory was improved, whereas in others it remained unaffected by donepezil. In a sleep deprivation trial, donepezil reduced the memory and attention deficits resulting from 24h of sleep deprivation. Two studies reported even transient negative effects. Regarding the safety profile of donepezil, these studies found that it was rather well tolerated. In any case, since large longitudinal studies are not available no conclusions can be drawn. Seven small studies about the effects of a single dose of memantine, and one study with a single dose of rivastigmine have been reported. Again, these studies are not adequate to answer our research question. If, as here and elsewhere suggested, the concept of pharmaceutical neuroenhancement is not to be rejected in principle, the decision of healthy individuals to take drugs for the purpose of neuroenhancement should be based on exhaustive information. At the moment, the research that would support or oppose the use of acetylcholinesterase inhibitors and memantine for neuroenhancement by healthy individuals has not yet been performed.
Drug treatment of Alzheimer's patients leads to expression changes in peripheral blood cells.
Alzheimers Dement. 2010 Feb 23;
Calciano MA, Zhou W, Snyder PJ, Einstein R
BACKGROUND: Increasing cholinergic activity has been the primary mechanism for treating dementia due to Alzheimer's disease. However, the effectiveness of cholinesterase inhibitors (ChEIs) is still widely debated. The identification of specific biomarkers capable of identifying patients more likely to respond to these treatments could potentially provide specific evidence to clearly address this controversy through patient stratification. The goal of this study was to determine the feasibility of discovering biomarkers specific for the treatment of Alzheimer's disease. METHODS: Peripheral blood was collected from a cohort of patients treated with different ChEIs. Total RNA was isolated and profiled on the human Genome-Wide SpliceArray (GWSA) to test the feasibility of discriminating the different treatment subgroups of subjects based on the expression patterns generated from the Genome-Wide SpliceArray. RESULTS: Specific expression differences were identified for the various treatment groups that lead to a clear separation between patients treated with ChEIs versus naïve patients when Principal Component Analysis was performed on probe sets selected for differential expression. In addition, specific probe sets were identified to be dependent on the inhibitor used among the treated patients. CONCLUSIONS: Distinct separation between non-treated, galantamine, donepezil, and rivastigmine-treated patients was clearly identified based on small sets of expression probes. The ability to identify drug-specific treatment expression differences strengthens the potential for using peripheral gene signatures for the identification of individuals responding to drug treatment.
Pharmacol Biochem Behav. 2010 Feb 23;
Myhrer T, Enger S, Aas P
Acetylcholinesterase inhibitors in combination with an anticholinergic, particularly anticholinergics with antiglutamatergic properties, can effectively protect against nerve agent-induced seizures and lethality. The objective of the present study was to examine potential behavioral side effects of the anticholinesterases physostigmine (0.1mg/kg), galantamine (3mg/kg), huperzine (0.5mg/kg), and donepezil (2.5mg/kg) alone or each drug in combination with anticholinergic procyclidine (3mg/kg). The results showed that rats injected intraperitoneally with galantamine displayed a mild cognitive deficit in terms of reduced preference for novelty that was similarly found among animals treated with procyclidine combined with either galantamine or donepezil. Locomotor activity and rearing were radically depressed in all groups treated with anticholinesterases as well as in combination with procyclidine. Reductions in activity were most prominent for rats injected with galantamine alone. Equalizing effects of cholinesterase inhibitors and anticholinergics were absent in the present context. Findings from previous studies that both systemic and local (amygdala) application of physostigmine cause increased fear-motivated freezing response in rats, may explain the marked reductions in activity among the present rats. In view of these findings, use of anticholinesterases (crossing the blood-brain barrier) as prophylactics against nerve agents must be carefully examined to avoid severe side effects.
Eur J Pharmacol. 2010 Feb 23;
Vicente MI, Costa PF, Lima PA
Galantamine, one of the major drugs used in Alzheimer's disease therapy, is a relatively weak acetylcholinesterase inhibitor and an allosteric potentiating ligand of nicotinic acetylcholine receptors. However, a role in the control of excitability has also been attributed to galantamine via modulation of K(+) currents in central neurones. To further investigate the effect of galantamine on voltage-activated K(+) currents, we performed whole-cell voltage-clamp recordings in differentiated neuroblastoma N1E-115 cells and in dissociated rat CA1 neurones. In both cell models, one can identify two main voltage-activated K(+) current components: a relatively fast inactivating component (Ifast; time constant approximately hundred milliseconds) and a slowly inactivating one (Islow; time constant approximately 1s). We show that galantamine (1pM-300microM) inhibits selectively Islow, exhibiting a dual dose-response relationship, in both differentiated N1E-115 cells and CA1 neurones. We also demonstrate that, in contrast with what was previously reported, galantamine-induced inhibition is not due to a shift on the steady-state inactivation and activation curves. Additionally, we characterized a methodological artefact that affects voltage-dependence as a function of time in whole-cell configuration, observed in both cell models. By resolving an inhibitory role on K(+) currents in a non-central neuronal system and in hippocampal neurones, we are attributing a widespread role of galantamine on the modulation of cell excitability. The present results are relevant in the clinical context, since the effects at low dosages suggest that galantamine-induced K(+) current inhibition may contribute to the efficiency of galantamine in the treatment of Alzheimer's disease.