Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.8 (cholinesterase)
12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Traditionally, the neuropsychiatric symptoms of Alzheimer's disease (AD) have been managed with neuroleptics or benzodiazepines, which have serious side effects. Preliminary observations suggest the possible value of cholinesterase inhibitors in the amelioration of psychotic symptoms in patients with dementia of the Alzheimer's type, dementia with Lewy bodies, and in patients with Parkinson's disease. Twelve inpatients with AD with psychotic symptoms and lack of improvement of their delusions/hallucinations during perphenazine treatment (8 mg/day) for 3 weeks received random open-label donepezil 5 mg daily in addition to an ongoing treatment of 8 mg/day perphenazine or 16 mg/day perphenazine. Assessments conducted at baseline and after weeks 2 and 4 included the Mini-Mental State Examination, the Global Deterioration Scale, the Positive and Negative Symptoms Scale, and the Clinical Global Impressions scale. Frequency of extrapyramidal symptoms was measured according to the Abnormal Involuntary Movement Scale. The donepezil-perphenazine group exhibited substantially greater and clinical improvements in mental state. At the end of the trial (4 weeks), Positive and Negative Symptoms Scale scores revealed significant differences between both groups (p = 0.006). The Clinical Global Impressions scale and the Mini-Mental State Examination scores also showed significant differences between the donepezil-perphenazine group and the perphenazine group (p = 0.028 and p = 0.027 respectively). No significant differences were found in the Global Deterioration Scale scores. Abnormal Involuntary Movement Scale scores showed a significant deterioration in extrapyramidal symptoms in the perphenazine group compared with the donepezil-perphenazine group (p = 0.016). Donepezil augmentation of neuroleptics may be appropriate for those patients for whom neuroleptic monotherapy either does not lead to symptom remission or is associated with intolerable adverse effects. This was an open-label study and there is need for larger studies with double-blind control and a long-term study design to define the efficacy of donepezil for patients with AD and psychotic symptoms.
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PMID:Donepezil as add-on treatment of psychotic symptoms in patients with dementia of the Alzheimer's type. 1267 28

Dementia with Lewy bodies (DLB) accounts for 15-20% of all autopsy confirmed dementias in old age. Characteristic histopathological changes are intracellular Lewy bodies and Lewy neurites, with abundant senile plaques but sparse neurofibrillary tangles. Core clinical features are fluctuating cognitive impairment, persistent visual hallucinations and extrapyramidal motor symptoms (parkinsonism). One of these core features has to be present for a diagnosis of possible DLB, and two for probable DLB. Supportive features are repeated falls, syncope, transient loss of consciousness, neuroleptic sensitivity, delusions and hallucinations in other modalities. DLB is clinically under-diagnosed and frequently misclassified as systemic delirium or dementia due to Alzheimer's disease or cerebrovascular disease. Therapeutic approaches to DLB can pose difficult dilemmas in pharmacological management. Neuroleptic medication is relatively contraindicated because some patients show severe neuroleptic sensitivity, which is associated with increased morbidity and mortality. Antiparkinsonian medication has the potential to exacerbate psychotic symptoms and may be relatively ineffective at relieving extrapyramidal motor symptoms. Recently there is converging evidence that treatment with cholinesterase inhibitors can offer a safe alternative for the symptomatic treatment of cognitive and neuropsychiatric features in DLB. This review will focus on the clinical characteristics of DLB, its differential diagnosis and on possible management strategies.
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PMID:Dementia with lewy bodies--diagnosis and treatment. 1270 40

Psychosis only rarely occurs in patients with untreated Parkinson's disease. Much more commonly, psychosis is induced by drug therapy for Parkinson's disease and is the strongest known risk factor for nursing home placement. Delusions are less frequent than hallucinations, but are more concerning as they are often paranoid in nature. Treatment begins with a search for correctable infectious, toxic, and metabolic aetiologies. If symptoms persist, anti-Parkinson's disease medications are slowly reduced. However, withdrawal of these drugs usually worsens parkinsonism and is often not tolerated. Certain atypical antipsychotics can be used to treat psychosis without compromising motor function. The choice of atypical antipsychotic is largely based on ease of use and adverse effect profile as most have comparable efficacy in improving psychosis. Currently, there are five marketed atypical drugs - clozapine, risperidone, olanzapine, quetiapine and ziprasidone. Ziprasidone is the only agent whose adverse effect profile has not been reported in Parkinson's disease. The most common adverse effects of clozapine in Parkinson's disease are sedation, orthostatic hypotension and sialorrhoea. Sedation is generally helpful since these patients are frequently awake at night and tend to have worse behavioural problems then. Clozapine does not induce deterioration of motor function, but it has the potential to cause agranulocytosis, which is idiosyncratic and not dose-related. In risperidone-treated Parkinson's disease patients, reported adverse effects include somnolence, sialorrhoea, dizziness, palpitations, constipation, delirium, fatigue, leg cramps, depression, urinary incontinence and hypotension. Although in some Parkinson's disease studies, risperidone has been well tolerated, others have shown that many patients are unable to tolerate the drug due to deterioration of motor function. While an initial study of olanzapine in Parkinson's disease psychosis showed the drug to be effective without deterioration of motor function, succeeding reports demonstrated a deleterious effect of the drug on motor functioning. The most common adverse effects of quetiapine in Parkinson's disease patients are sedation and orthostatic hypotension. There is a lack of double-blind trials; however, cumulative reports involving >200 Parkinson's disease patients strongly suggest that quetiapine is well tolerated and effective. Unlike clozapine, it does not improve tremor and may induce mild deterioration of motor function. Recently, cholinesterase inhibitors have been reported to alleviate psychosis in Parkinson's disease. Although ondansetron, an antiemetic with antiserotonergic properties, has been reported to relieve psychosis in Parkinson's disease, its prohibitive cost has prevented further study in this population. Electroconvulsive treatment is generally reserved for the patient with psychotic depression who is unable to tolerate any pharmacological therapy.
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PMID:Treatment of psychosis in Parkinson's disease: safety considerations. 1281 32

Numerous advances have taken place in the pharmacological management of Parkinson disease (PD) in recent years. Some of the more clinically relevant will be discussed in the text that follows. New drugs have been developed to treat or prevent the motor fluctuations and dyskinesias that occur frequently with the continuous use of levodopa. Such drugs include the catechol-O-methyl-transferase (COMT) inhibitors, such as tolcapone and entecapone, and new dopamine (DA) agonists with long half lives such as cabergoline, pramipexole or ropirinole. Also new, atyical, antipsychotics have appeared which have revolutionized the treatment of PD since they allow us to control hallucinations and other psychotic behaviour without worsening of motor function. Finally preliminary reports suggest that cholinesterase inhibitors, such as rivastigmine, can be usefull in the management of cognitive impairment in PD, one of the most difficult clinical problems encountered in the management of this neurodegenerative disorder.
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PMID:Advances in the pharmacological management of Parkinson disease. 1283 Sep 29

THE MAJOR THERAPEUTIC TRENDS: The treatment of psychosis in late life depends on the etiology of the delusion but also on its behavioral consequences (agitation, aggressiveness). We distinguish between the treatment of long term old psychosis and delusions occurring late in life (after the age of 60). FOR THE OLD PSYCHOSES: The reduction in the symptomatology often permits a reduction in the doses and the relay to atypical neuroleptics with improved tolerance. FOR DELUSIONS OCCURRING LATE IN LIFE: The treatment will be adjusted to the etiology of the delusion: delirious states associated with dementia, thymus delusion, schizophrenic or non-schizophrenic psychosis, delusion related to cerebral-vascular disorders or to sensorial dysafferentation. One should note that emotional and delusional disorders are often concomitant in the elderly. THE TWO TREATMENT AXES: The first therapeutic element is non-pharmacological: reassurance or even brief psychotherapy, family counseling and prevention of enhancing, notably environmental, factors. The pharmacological element preferably includes atypical anti-psychotics, antidepressants in some cases together with anti-epileptics in cases of concomitant rebellious aggressiveness. In cases of dementia with cholinergic deficiency (Alzheimer, Lewy body dementia, mixed dementia) cholinesterase inhibitors have demonstrated their efficacy on the hallucinations. Advice for a pertinent strategy of action should be provided.
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PMID:[Delirious states in elderly persons. Therapeutic modalities]. 1285 35

The defining characteristic of Alzheimer's disease is cognitive impairment, but commonly this impairment is accompanied by mood and behavioral symptoms such as depression, anxiety, irritability, inappropriate behavior, sleep disturbance, psychosis, and agitation. The symptoms of Alzheimer's disease are not normative to the aging process. Diagnosis of Alzheimer's disease in the majority of cases can be made with confidence through office-based clinical assessment and informant interview. Alzheimer's disease is the most common of the dementing disorders and is exponentially increasing in incidence, projected to affect 8.64 million people in the United States by the year 2047. At present, no treatment can prevent or cure Alzheimer's disease, and the fact that Alzheimer's affects a geriatric population makes treatment all the more challenging. Therapies that could delay onset of symptoms even briefly would have a major impact on public health. As the prevalence of Alzheimer's disease increases, researchers are examining the efficacy of treatment options beyond the realm of the established cholinesterase inhibitors.
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PMID:Diagnosis and treatment of Alzheimer's disease. 1293 67

Dementia in Parkinson's disease (PDD) is a frequent and distressing complication with major consequences. Clinical and pathological features closely link PDD and dementia with Lewy bodies (DLB), suggesting they represent part of the same disease spectrum. Although dopaminergic deficiency primarily determines the akinetic-rigid symptoms of PDD and DLB, there is overwhelming evidence that cholinergic dysfunction underpins many of the cognitive impairments and psychotic features. Open-label studies have suggested that cholinesterase inhibitor drugs may exert positive effects upon all aspects of the neuropsychiatric syndrome in PDD and DLB but particularly apathy, anxiety, impaired attention, hallucinations, delusions, sleep disturbance, and cognitive test performance. Worsening of extrapyramidal motor features is reported only rarely. Initial double-blind, placebo-controlled studies in PDD and DLB have so far confirmed these encouraging results. Early identification of PD patients at greatest risk of developing dementia would permit early use of disease modifying treatments which represent the "golden fleece" management approach to these groups.
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PMID:Current treatment of dementia with Lewy bodies and dementia associated with Parkinson's disease. 1450 59

Psychosis is common in patients with Alzheimer's disease (AD) and contributes substantially to patient morbidity and caregiver distress. Antipsychotic medications are used to treat psychosis and other psychiatric or behavioral symptoms in AD, although optimal treatment guidelines have been elusive. Choosing the most advantageous medication for an individual patient is challenging. This article provides an overview of clinical management principles and medication treatment strategies for patients with AD and psychosis. Effects of individual medications are also described. Medications in the conventional neuroleptic, atypical antipsychotic, cholinesterase inhibitor, and serotonergic classes have been shown to ameliorate psychosis and behavioral symptoms in patients with AD, although the evidence is not conclusive for many medications. Side effects vary substantially across medication classes and modestly among individual patients. Improvement in agitation, aggression, or other behaviors with antipsychotic medication treatment may not depend on distinct antipsychotic effects. In contrast, there is preliminary evidence that delusions and hallucinations may respond to treatment with medications outside the antipsychotic class. Many important clinical questions warrant further research study. In particular, studies to compare how individual symptoms respond to different medications, and to examine how to best manage overlapping symptoms or incomplete treatment response are needed.
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PMID:Psychosis and antipsychotic medications in Alzheimer's disease: clinical management and research perspectives. 1456

The syndrome of dementia with Lewy bodies (DLB) is characterised by the clinical triad of fluctuating cognitive impairment, recurrent visual hallucinations and spontaneous motor features of Parkinsonism. In an attempt to define DLB as a distinct clinical syndrome separate from Alzheimer's disease (AD) and Parkinson's disease (PD) with dementia, a consensus workshop in 1995 established a new set of diagnostic criteria. Dementia that precedes or accompanies the onset of spontaneous (i.e., not neuroleptic-induced) Parkinsonism is termed DLB. In addition, fluctuations in alertness, cognition and function and visual hallucinations are emphasised and included as core features of DLB. The degree to which an individual patient exhibits cognitive impairment, behavioural problems and Parkinsonian features is variable. Therefore, treatment must be individualised. Although there are no officially approved drugs for DLB, limited experience from clinical trials, as well as past experience with the treatment of AD and PD patients, provide some basis for making drug choices. The cholinergic deficit seen in DLB makes cholinesterase inhibitor drugs the mainstay of treatment for cognitive impairment. This class of drugs has also shown therapeutic benefit in reducing hallucinations and other neuropsychiatric symptoms of the disease. Because of their relatively greater therapeutic window, cholinesterase inhibitors are also used as first-line therapy for the treatment of psychosis in DLB. Patients with DLB are extremely sensitive to the extrapyramidal side effects of neuroleptic medications. Thus, only atypical antipsychotic agents such as quetiapine, should be considered as alternative treatment for psychosis. Anxiety and depression are best treated with selective serotonin re-uptake inhibitors, whereas REM sleep behaviour disorder may be treated with low dose clonazepam. Parkinsonism responds to dopaminergic agents; however, precipitation or aggravation of hallucinosis may occur. Levodopa is preferred over dopamine agonists due to its lower propensity to cause hallucinations and somnolence. As the diagnostic criteria for DLB become more refined and validated by postmortem studies, it is hoped that rigorous, well-designed trials will be performed, aimed at alleviating the primary target symptoms of dementia, psychosis and Parkinsonism.
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PMID:Pharmacotherapy of dementia with Lewy bodies. 1459 56

Cholinesterase inhibitors are commonly used to improve cognition and treat psychosis and other behavioral symptoms in Alzheimer's disease, Parkinson's disease, and other neuropsychiatric conditions. However, mechanisms may exist that down-regulate the synaptic response to altered cholinergic transmission, thus limiting the efficacy of cholinomimetics in treating disease. Acetylcholinesterase knockout (AChE-/-) mice were used to investigate the neuronal adaptations to diminished synaptic acetylcholine (ACh) metabolism. The striatum of AChE-/- mice showed no changes in choline acetyltransferase activity or levels of the vesicular ACh transporter but showed striking 60% increases in the levels of the highaffinity choline transporter. This transporter takes choline from the synapse into the neuron for resynthesis of ACh. In addition, the striata of AChE-/- mice showed dramatic reductions in levels of the M1, M2, and M4 muscarinic ACh receptors (mAChRs), but no alterations in dopamine receptors or the beta2 subunit of nicotinic receptors. M1, M2, and M4 also showed decreased dendritic and cell surface distributions and enhanced intracellular localizations in striatal neurons of AChE-/- mice. mAChR antagonist treatment reversed the shifts in mAChR distribution, indicating that internalized receptors in AChE-/- mice can recover to basal distributions. Finally, AChE-/- mice showed increased sensitivity to mAChR antagonist-induced increases in locomotor activity, demonstrating functional mAChR down-regulation. mAChR downregulation in AChE-/- mice has important implications for the long-term use of cholinesterase inhibitors and other cholinomimetics in treating disorders characterized by perturbed cholinergic function.
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PMID:Altered striatal function and muscarinic cholinergic receptors in acetylcholinesterase knockout mice. 1464 60


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