Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The safety of tacrine (Cognex), a centrally active, reversible acetylcholinesterase inhibitor approved in 1993 for the treatment of mild to moderate dementia of the Alzheimer type, was evaluated in 2,706 patients with Alzheimer disease (AD) in clinical trials and in 9861 patients with AD in a treatment investigational new drug (TIND) program. More than 190,000 patients in the United States received tacrine during the first 2 years following marketing approval. The most common tacrine-associated adverse events were elevated liver transaminase levels [alanine aminotransferase (ALT) and, to a lesser degree, aspartate aminotransferase] and peripheral cholinergic events involving primarily the digestive system (nausea, vomiting, diarrhea, dyspepsia, anorexia, and weight loss). Based on clinical trial experience, potentially clinically significant (>3 x upper limit of normal) ALT elevations occurred in 25% of patients, requiring routine monitoring early in treatment. The elevations were almost always asymptomatic, rarely accompanied by significant increases in bilirubin, and related to time on drug rather than to dose (90% occurred within the first 12 weeks of treatment). Gastrointestinal events were related to dose and generally of mild to moderate intensity. Tacrine-associated events, including ALT elevations, were reversible. Cholinergic events were manageable with dosage adjustment. Tacrine was not associated with permanent liver injury in clinical trials or a TIND setting.
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PMID:Safety of tacrine: clinical trials, treatment IND, and postmarketing experience. 965 Nov 38

According to the cholinergic hypothesis, the impairment of cognitive function and the behavioural disturbances that affect patients with Alzheimer's disease are mainly due to cortical deficiencies in cholinergic transmission. Numerous cholinesterase inhibitors have been investigated for treatment of this disease, the rationale being to support the cholinergic system by blocking the degradation of acetylcholine released from presynaptic neurons. These drugs can be classified as reversible (tacrine, donepezil and galantamine), pseudo-reversible (physostigmine, eptastigmine and rivastigmine) or irreversible (metrifonate) enzyme inhibitors. This article reviews efficacy and tolerability results from 6-month placebo-controlled studies of 7 cholinesterase inhibitors: tacrine (80 to 160 mg/day), donepezil (5 to 10 mg/day), rivastigmine (1 to 12 mg/day), metrifonate (30 to 80 mg/day), eptastigmine (30 to 60 mg/day), physostigmine (30 to 36 mg/day) and galantamine (8 to 32 mg/day). All these agents have demonstrated a statistically significant, although modest, effect versus placebo on the cognitive and global performance of patients with Alzheimer's disease. Dramatic clinical response has been seen in only 3 to 5% of patients. There are no major differences in terms of efficacy between the different drugs. The mean difference between drug and placebo effects on standardised psychometric scales is about 2 to 4 points on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog; a 70-point cognitive scale) and 0.2 to 0.5 points on the Clinician's Interview-Based Impression of Change with Caregiver Input (CIBIC-Plus; a 7-point global scale), or 5 to 14% of the average value of the scales. The most common adverse effects observed after administration of cholinesterase inhibitors are nausea, vomiting, diarrhoea, dizziness, asthenia and anorexia, all symptoms linked to cholinergic overstimulation. These effects are dose related and largely depend on the degree of cholinesterase inhibition. Also important is the rate of onset of cholinesterase inhibition, which depends on the kinetics of enzyme inhibition, the presence and rate of titration, and the pharmacodynamic peak-to-trough fluctuations. A model predicting the incidence of nausea based on acetylcholinesterase inhibition and the half-life of acetylcholinesterase recovery is proposed. In conclusion, cholinesterase inhibitors are the only pharmacological agents proved to be effective for the treatment of Alzheimer's disease in large, long term, double-blind, placebo-controlled trials. While the efficacy of different cholinesterase inhibitors is similar, their tolerability profiles differ. For example, the incidence of nausea (in excess of that seen with placebo) at cognitively effective dosages ranges from 1% with eptastigmine 60 mg/day to 53% with physostigmine 30 mg/day. Differences in tolerability profile may be due to the extent of peripheral acetylcholinesterase inhibition needed to reach clinical efficacy. Other contributing pharmacodynamic factors are the rate of onset of and fluctuations in acetylcholinesterase inhibition at steady state.
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PMID:Pharmacodynamic-tolerability relationships of cholinesterase inhibitors for Alzheimer's disease. 1147 43

The management of dementia patients encompasses pharmacologic, behavioral, and psychosocial intervention strategies. Before pharmacologic intervention is instituted, it is important that sources of excess disability and comorbidity be eliminated or reduced. Identification of comorbid medical and psychiatric conditions, such as depression and delirium, should be identified and appropriately treated. Providing caregivers with education, support, and practical advice is a critical component of the management of the demented patient. The current standard of care for pharmacologic management of the cognitive and functional disabilities of AD consists of the combination of a cholinesterase inhibitor and high-dose vitamin E. This standard is based on the results of large-scale, double-blind, placebo-controlled trials. Cholinesterase inhibitors are the only FDA-approved pharmacologic treatments for AD. Cholinesterase inhibitors have been shown to be effective in the treatment of the cognitive, behavioral, and functional deficits of AD. Large-scale placebo-controlled trials of tacrine, donepezil, rivastigmine, and galantamine have demonstrated moderate benefits in patients with mild to moderate AD. Donepezil, rivastigmine, and galantamine are the first-line choices in the treatment of AD because of their lack of hepatotoxicity, ease of administration, few significant drug-drug interactions, and mild to moderate side effects. There are few contraindications to the use of cholinesterase inhibitors. Known hypersensitivity to a specific drug or its derivatives is the only true contraindication. Cautious administration of cholinesterase inhibitors is advised in patients who have a previous history of allergy or adverse reactions to prior cholinesterase inhibitors, severe liver disease, preexisting bradycardia, peptic ulcer disease, current alcoholism, asthma, or chronic obstructive pulmonary disease. Nausea, vomiting, diarrhea, and anorexia are the most common side effects of cholinesterase inhibitors. These gastrointestinal side effects can be minimized by gradual dose increases, administration with food, adequate hydration, and judicious use of an antiemetic. Vitamin E has been demonstrated to slow the progression of AD in several small and one large placebo-controlled trials. Because of its low cost and safety, it is recommended in addition to a cholinesterase inhibitor for the treatment of AD. There are no FDA-approved treatments for DLB and VaD. One small placebo-controlled trial demonstrated that rivastigmine may be effective in the treatment of DLB. More large-scale placebo-controlled trials are needed to confirm the results of this study. Treatment of VaD focuses on the control, identification, and management of cerebrovascular disease and vascular risk factors. Although there are no peer-reviewed reports on the efficacy of cholinesterase inhibitors for VaD or mixed AD/VaD, early reports suggest that these agents may also be effective for mixed AD/VaD. The indications for the use of cholinesterase inhibitor drugs are eventually likely to broaden to include DLB, mixed AD/VaD, and AD in its more advanced stages.
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PMID:Pharmacologic treatments of dementia. 1217 Oct 61

The objective of this study was to evaluate the safety, tolerability, maximum tolerated dose, pharmacokinetics, and pharmacodynamics of five fixed doses of ganstigmine (CHF 2819) in patients with probable Alzheimer's disease (AD). This randomized, double-blind, placebo-controlled trial evaluated five dose levels (5, 7.5, 10, 12.5, and 15 mg) administered orally once daily for 7 days. Adverse events and continuous telemetry were collected on successive panels of six patients (five active, one placebo). Acetylcholinesterase, butyrylcholinesterase, and plasma drug levels were measured. A total of 29 patients were randomized and 18 completed the study. A total of seven patients, including five of five in the 12.5-mg panel, discontinued because of adverse events. Four patients were withdrawn administratively from the first panel while an episode of atrial fibrillation (the only serious adverse event) was investigated. This panel was then repeated. Mild, transient headache or nausea were the most commonly reported adverse events. Multiple moderate adverse events in the 12.5-mg panel (including nausea, vomiting, and anorexia) led to the decision not to proceed with a 15-mg panel. Ten milligrams was determined to be the maximum tolerated dose. Ganstigmine exhibited nonlinear pharmacokinetics, was absorbed rapidly, and reached peak concentrations within 1 hour. Acetylcholinesterase inhibition was dose dependent and lasted as long as 24 hours. Ganstigmine, a novel cholinesterase inhibitor, was well tolerated within a dosing range of 5 to 10 mg. Once-daily dosing is supported by data on acetylcholinesterase inhibition.
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PMID:First clinical evaluation of ganstigmine in patients with probable Alzheimer's disease. 1278 20

Alzheimer's disease is characterized by the development of senile plaques and neurofibrillary tangles, which are associated with neuronal destruction, particularly in cholinergic neurons. Drugs that inhibit the degradation of acetylcholine within synapses are the mainstay of therapy. Donepezil, rivastigmine, and galantamine are safe but have potentially troublesome cholinergic side effects, including nausea, anorexia, diarrhea, vomiting, and weight loss. These adverse reactions are often self-limited and can be minimized by slow drug titration. Acetylcholinesterase inhibitors appear to be effective, but the magnitude of benefit may be greater in clinical trials than in practice. The drugs clearly improve cognition, but evidence is less robust for benefits in delaying nursing home placement and improving functional ability and behaviors. Benefit for vitamin E or selegiline has been suggested, but supporting evidence is not strong. Most guidelines for monitoring drug therapy in patients with Alzheimer's disease recommend periodic measurements of cognition and functional ability. The guidelines generally advise discontinuing therapy with acetylcholinesterase inhibitors when dementia becomes severe.
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PMID:Pharmacologic treatment of Alzheimer's disease: an update. 1456 91

Observations on the neurochemistry of dementia with Lewy bodies (DLB) have suggested that cholinesterase inhibitors (ChEIs) might be beneficial in treating some clinical symptoms of DLB. A 24-week, multicenter open-label study was designed to assess the safety and efficacy of the ChEI galantamine in patients with DLB, and an interim analysis of results was performed at 12 weeks. Efficacy analyses were performed on data from 25 patients. Scores on the Neuropsychiatric Inventory (NPI-12) improved (decreased) by 7.52 points over the 12 weeks (marginally significant, p = 0.061). NPI-12 scores decreased by half in 12 of the 25 patients. Highly significant improvement was observed in scores on the NPI-4 subscale (delusions, hallucinations, apathy, and depression: p = 0.003). Scores on the Clinician's Global Impression of Change (CGIC) improved by 0.95 points (significant, p = 0.02). Improvements also were found in secondary efficacy variables, including cognitive, functional, activities of daily living, sleep and confusion assessments. Motor scores, as measured by the UPDRS motor subscale, showed mild improvement, which demonstrates that galantamine has no adverse effect on parkinsonian symptoms. Adverse events generally were transient and of mild-to-moderate intensity. Two of the 25 patients discontinued galantamine because of nausea and anorexia. One serious adverse event was recorded, but it was judged to be unrelated to the study medication.
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PMID:Efficacy and safety of galantamine in patients with dementia with Lewy bodies: a 12-week interim analysis. 1467 68

This article reviews the piperidine derivative, donepezil hydrochloride (E2020, Aricept), a reversible central acetylcholinesterase inhibitor currently approved for treatment of mild-to-moderate Alzheimer's disease. Donepezil is well absorbed orally, unaffected by food or by time of administration; it reaches therapeutic levels in doses of 5-10 mg/day and peak plasma concentrations are obtained 3-4 h after oral administration. A single bedtime dose is recommended due to the long elimination half-life of the drug (70 h). Donepezil does not cause liver toxicity or significant drug interactions and is relatively well-tolerated. Initial side effects include nausea, vomiting, diarrhoea, insomnia, muscle cramps, fatigue, anorexia and syncope. Caution is advised in patients with bradycardia. Long-term use of donepezil in AD has been found to delay nursing-home placement and to result in caregiver respite. Donepezil also slows deterioration of cognition and global function in patients with moderate-to-severe AD, with improvement of abnormal behaviours. In addition to AD, donepezil demonstrates significant improvement in cognition, global function and activities of daily living in comparison with placebo-treated patients with vascular dementia and has potential therapeutic benefit for other neurological conditions.
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PMID:Donepezil: a clinical review of current and emerging indications. 1468 Apr 45

Non-ulcer dyspepsia is a common clinical disorder characterised by reduced gastric motility. Safety concerns have restricted use of currently available prokinetic drugs. Itopride is a new safer prokinetic drug with dopamine D2 antagonism and acetylcholinesterase inhibitory actions. The ENGIP-II study was conducted to investigate the efficacy, and safety of itopride in patients of non-ulcer dyspepsia. There were significant reductions in upper abdominal pain, heartburn frequency, gastro-oesophageal regurgitation, nausea, bloating, early satiety after meals at day 3 only; whereas significant improvements were noted in belching, anorexia at day 6 and in vomiting at day 9. Thus, ENGIP-II study shows that itopride was well tolerated patients and appears to be the drug of choice in patients with non-ulcer dyspepsia.
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PMID:Evaluation of new gastro-intestinal prokinetic (ENGIP-II) study. 1682 70

Caregivers play a determining role in choosing treatments for persons with Alzheimer's disease. The objective of this study was to examine caregivers' willingness to have persons with Alzheimer's disease continue taking cholinesterase inhibitors in the event that any 1 of 11 adverse effects was to occur. Data were gathered via postal questionnaire from 375 caregivers in Montreal. Sixty-four per cent of caregivers responded ( n = 201), and most (> or =59%) were willing to continue treatment if persons with Alzheimer's disease suffered from weight loss or loss of appetite. However, most (> or =53%) were not willing to continue treatment in the event of headache, dizziness, nausea, diarrhea, vomiting, drop in blood pressure, insomnia, muscle cramps, or stomach bleeding. The use of cholinesterase inhibitors by persons with Alzheimer's disease was positively associated with caregivers' willingness to accept greater numbers of adverse effects (adjusted relative risk = 1.97; 95% CI = 1.11 to 3.61). Caregivers appear to make a risk-benefit assessment when they decide whether or not care-recipients should continue pharmacotherapy in the event of adverse effects.
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PMID:Caregiver acceptance of adverse effects and use of cholinesterase inhibitors in Alzheimer's disease. 1823 27

In the present work the effect of intramuscular administration of 30.000, 50.000 and 100.000 IU of vitamin A palmitate daily for seven days, respectively, on the liver enzyme activity in 45 white male Wistar rats, aged 12 weeks and weighing 180-200 g, have been studied. The group control was integrated by 15 healthy rats with similar characteristics (strain, gender, age and weight) to treated animals. Food and water consumption and body weights were recorded at the end of the experimental period. Rats were observed for clinical signs of toxicity. At the end of the study, rats were sacrificed under ether anesthesia. Liver samples were taken for the determination of enzyme activity. Administration of excess of vitamin A produced a significant (p < 0.05) increase in the content of liver vitamin A, determined diverse and variable clinical signs (such as, anorexia, loss of body weight, alopecia, conjunctivitis, external and internal hemorrhages, skin abnormalities and death) and increased (p < 0.05) the activity of the following enzymes: alanine aminotransferase, aspartate aminotransferase, acid maltase (acid alpha-1,4-glucosidase), acid proteases, lactate dehydrogenase and alkaline phosphatase while glucose-6-phosphatase, glycogen phosphorylase, alpha-amylase, cholinesterase and arginase decreased (p < 0.05) as compared with untreated controls. These changes depend on the doses given of vitamin A. In conclusion, our results provide evidence that short-term administration of high doses of vitamin A determined diverse and variable clinical signs and produces a marked alteration of activity of liver enzymes.
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PMID:[Clinical and biochemical alterations in rats treated with high doses of vitamin A]. 1827


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