Increased Alzheimer pathology in Parkinson's disease related to antimuscarinic drugs

Geropharmacology: a primer for advanced practice. Acute care and critical care nurses, part II

In the first part of this 2-part continuing education series, sources of medication errors were discussed. A predominant source of errors was the prescribing of potentially inappropriate medications for older adults. In this second part, drug classifications and drugs posing problems for older adults and cautions for advanced practice acute care and critical care nurses in their medication therapy management are highlighted. Cautions are advanced for anticholinergics, antihypertensives, analgesics, and psychotropics because of the severity of adverse reactions, including anticholinergic symptoms; mental status changes (especially confusion, sedation, delirium, and cognitive impairment); orthostatic hypotension; gastrointestinal tract problems (especially hemorrhage); depression; and neurobehavioral disturbances (agitation and aggressiveness). Risks of life-threatening outcomes associated with medications and adverse reactions are highlighted.

A novel adenosine A(1) and A(2A) receptor antagonist ASP5854 ameliorates motor impairment in MPTP-treated marmosets: comparison with existing anti-Parkinson's disease drugs

Recent evidence indicates that adenosine A(2A) receptor antagonists hold therapeutic potential for the treatment of Parkinson's disease (PD). A study on the novel adenosine A(1) and A(2A) receptor dual antagonist 5-[5-amino-3-(4-fluorophenyl)pyrazin-2-yl]-1-isopropylpyridine-2(1H)-one (ASP5854) showed it to be effective in various rodents models of PD and cognition. In the present study, we further investigated the potential of ASP5854 as an anti-PD drug using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets, which is a highly predictive model of clinical efficacy in PD, and compared its effect with those of existing anti-PD drugs. ASP5854 significantly and dose-dependently improved the total motor disability score for 7h at doses higher than 1mg/kg, and significantly increased total locomotor activity at doses higher than 0.1mg/kg without adverse effects. l-3,4-Dihydroxyphenylalanine+benserazide and bromocriptine also significantly improved the motor disability score and the hypolocomotion caused by MPTP treatment in a dose-dependent fashion. This amelioration was significant at 32+8 and 10-32 mg/kg, respectively, although bromocriptine induced severe emesis. Trihexiphenidyl also significantly improved the total motor disability score at doses of 10-32 mg/kg; however, while a significant increase in the total locomotor activity was observed at 10mg/kg, the drug induced ataxia-like behavior at 32 mg/kg. On the other hand, neither selegiline nor amantadine improved the total motor disability and hypolocomotion. These data substantiate the evidence that the novel adenosine antagonist ASP5854 exerts comparable anti-PD activity with existing anti-PD drugs, which indicates that ASP5854 might have potential to ameliorate motor deficits in PD.

Cholinergic treatments with emphasis on m1 muscarinic agonists as potential disease-modifying agents for Alzheimer's disease

The only prescribed drugs for treatment of Alzheimer's disease (AD) are acetylcholinesterase inhibitors (e.g., donepezil, rivastigmine, galantamine, and tacrine) and memantine, an NMDA antagonist. These drugs ameliorate mainly the symptoms of AD, such as cognitive impairments, rather than halting or preventing the causal neuropathology. There is currently no cure for AD and there is no way to stop its progression, yet there are numerous therapeutic approaches directed against various pathological hallmarks of AD that are extensively being pursued. In this context, the three major hallmark characteristics of AD (i.e., the CNS cholinergic hypofunction, formation of beta-amyloid plaques, and tangles containing hyperphosphorylated tau proteins) are apparently linked. Such linkages may have therapeutic implications, and this review is an attempt to analyze these versus the advantages and drawbacks of some cholinergic compounds, such as acetylcholinesterase inhibitors, M1 muscarinic agonists, M2 antagonists, and nicotinic agonists. Among the reviewed treatments, M1 selective agonists emerge, in particular, as potential disease modifiers.

Impact of anticholinergics on the aging brain: a review and practical application

Objective: in an effort to enhance medication prescribing for older adults and reduce the burden of cognitive impairment, this paper reviews the literature regarding the negative impact of anticholinergics on cognitive function and provides clinicians with a practical guidance for anticholinergic use in older adults. Methods: a Medline search identified studies evaluating the use of anticholinergics and the relationship between anticholinergics and cognitive impairment. Results: prescribing anticholinergics for older adults leads to acute cognitive impairment and, possibly, chronic cognitive deficits. Assessing anticholinergic burden with a simple scale may represent a useful noninvasive tool to optimize geriatric pharmacotherapy. Conclusion: more studies are needed to validate the Anticholinergic Cognitive Burden scale and establish therapeutic guidelines in the presence of cognitive anticholinergic adverse effects.

Dual use of bladder anticholinergics and cholinesterase inhibitors: long-term functional and cognitive outcomes

OBJECTIVES

To determine the cognitive and functional consequences of dual use of cholinesterase inhibitors (ChIs) and the bladder anticholinergics oxybutynin or tolterodine.

DESIGN

Prospective cohort study.

SETTING

Nursing homes (NHs) in the state of Indiana.

PARTICIPANTS

Three thousand five hundred thirty-six Medicaid-eligible NH residents aged 65 and older taking a ChI between January 1, 2003, and December 31, 2004. Residents were excluded if they were taking an anticholinergic other than oxybutynin or tolterodine.

MEASUREMENTS

Indiana Medicaid claims data were merged with data from the Minimum Data Set (MDS). Repeated-measures analyses were performed to assess the effects of dual therapy on change in cognitive function measured using the MDS Cognition Scale (MDS-COGS; scored 0-10) and change in activity of daily living (ADL) function using the seven ADL items in the MDS (scored 0-28). Potential covariates included age, sex, race, number of medications, and Charlson Comorbidity Index score.

RESULTS

Three hundred seventy-six (10.6%) residents were prescribed oxybutynin or tolterodine concomitantly with a ChI. In residents in the top quartile of ADL function, ADL function declined an average of 1.08 points per quarter when not taking bladder anticholinergics (ChI alone), compared with 1.62 points per quarter when taking dual therapy, a 50% greater rate in quarterly decline in ADL function (P=.01). There was no excess decline attributable to dual therapy in MDS-COGS scores or in ADL function for residents who started out with lower functioning.

CONCLUSION

In higher-functioning NH residents, dual use of ChIs and bladder anticholinergics may result in greater rates of functional decline than use of ChIs alone. The MDS-COGS may not be sensitive enough to detect differences in cognition due to dual use.

New approaches to understanding hallucinations in Parkinson's disease: phenomenology and possible origins

The authors review current literature on hallucinations in Parkinson's disease (PD). Recent neuropathological studies showed that hallucinations occur in synucleinopathies and are a significant predictor of Lewy Body depositions. Therefore, hallucinations are a hallmark of PD and of dementia with Lewy Bodies. Visual hallucinations are mostly complex and kinematic; preserved or disturbed insight on the nature of hallucinations is a major prognostic factor, although eventually all hallucinators will present with reduced insight. Current theories on the origin of hallucinations point to visual dysfunction, dream overflow and cognitive impairment, yet objection can be raised on each one of the putative models of hallucinations. Understanding of the origin of hallucinations is required in order to develop treatments: all treatment evaluations were focused in general on psychosis, and only clozapine obtained positive evidence-based ratings on efficacy. However, it is likely that cholinesterase inhibitors, antipsychotics and anti-5-hydroxytryptamine(3) agents and drugs acting on sleep regulation will have different and perhaps opposite effects on different types of hallucinations, whether they are accompanied by disturbed insight, sleep disorders or other psychotic features. Further studies will try to separate phenomenology and responses to treatment and will investigate the relevance of concomitant sleep disorders and abnormality of frontoparietal networks involved in the attention process.

Antimuscarinics for the treatment of overactive bladder: a review of central nervous system effects

Antimuscarinic drugs commonly used to treat overactive bladder are often associated with central nervous system (CNS) side effects including cognitive dysfunction, memory impairment, dizziness, fatigue, and headache. New agents show reduced CNS penetrance and better selectivity for the M3 muscarinic receptor. However, changes associated with aging may lead to alterations in blood-brain barrier permeability. Therefore, use of antimuscarinics in the elderly or in patients with Alzheimer's disease presents a significant challenge. This review highlights muscarinic receptor distribution and function in the CNS, provides a description and incidence of CNS side effects with therapy, offers information specific to currently available agents, and describes the use of antimuscarinics in special populations including children, the elderly, and patients with Alzheimer's disease.

Darifenacin: Pharmacology and Clinical Usage

Darifenacin is one of several recently approved antimuscarinics for the treatment of overactive bladder (OAB) and urge urinary incontinence. Darifenacin is an effective drug for the treatment of OAB and is tolerated by patients. Darifenacin's M3 selectivity is unique among antimuscarinics. This M3 selectivity could confer advantages in patients who have cardiovascular side effects (tachycardia), impaired cognition, complaints of dizziness, or sleep disturbances. In some studies, darifenacin caused less dry mouth than oxybutynin. Rates of constipation, although significant, are tolerated and rarely a cause for discontinuation in clinical trials. This review describes the role of M3 receptors and covers the mechanism of action, pharmacokinetic properties, clinical efficacy safety and tolerability, drug interactions, and dosing guidelines for darifenacin.

Neuroleptic drugs in dementia: benefits and harm

Neuroleptic (antipsychotic) drugs are often used to treat psychiatric symptoms frequently seen in dementia, but their use is controversial. We present a new meta-analysis to assess the efficacy of these drugs for the treatment of psychiatric symptoms in Alzheimer's disease, and discuss the more limited evidence for their potential benefits in other dementias. We recommend that these treatments be limited to the short-term treatment of psychiatric symptoms associated with serious distress or risk.

Brain perfusion effects of cholinesterase inhibitors in Parkinson’s disease with dementia

Several evidences suggest that cholinergic deficits may significantly contribute to dementia in Parkinson's disease (PDD) and acetylcholinesterase inhibitors (ChEIs) have been reported to improve cognitive symptoms in PDD, without worsening parkinsonism. Nineteen PDD patients underwent brain perfusion SPECT with (99m)Tc-ethyl cysteinate dimer after 6 months ChEIs treatment in order to evaluate the functional correlates of clinical improvement. A clear-cut cognitive improvement was reported in PDD patients with a significant improvement of ADAS-cog total score as well as of subscores exploring executive functions (p<0.01). MMSE total score did not significantly change after ChEIs but the subscore of attention significantly improved after therapy (p<0.01). No difference in motor performance as evaluated by UPDRS was reported. SPM analysis showed a significant increase of perfusion (p < 0.0001) in bilateral cingulate, and frontal regions after ChEIs. Our data confirm the efficacy of ChEIs in the treatment of dementia associated with PD mainly on attention and executive functions, and the functional findings indicate that this cognitive improvement could be associated with a sort of pharmacological frontal "re-afferentation".

Muscarinic receptors: their distribution and function in body systems, and the implications for treating overactive bladder

1. The effectiveness of antimuscarinic agents in the treatment of the overactive bladder (OAB) syndrome is thought to arise through blockade of bladder muscarinic receptors located on detrusor smooth muscle cells, as well as on nondetrusor structures. 2. Muscarinic M3 receptors are primarily responsible for detrusor contraction. Limited evidence exists to suggest that M2 receptors may have a role in mediating indirect contractions and/or inhibition of detrusor relaxation. In addition, there is evidence that muscarinic receptors located in the urothelium/suburothelium and on afferent nerves may contribute to the pathophysiology of OAB. Blockade of these receptors may also contribute to the clinical efficacy of antimuscarinic agents. 3. Although the role of muscarinic receptors in the bladder, other than M3 receptors, remains unclear, their role in other body systems is becoming increasingly well established, with emerging evidence supporting a wide range of diverse functions. Blockade of these functions by muscarinic receptor antagonists can lead to similarly diverse adverse effects associated with antimuscarinic treatment, with the range of effects observed varying according to the different receptor subtypes affected. 4. This review explores the evolving understanding of muscarinic receptor functions throughout the body, with particular focus on the bladder, gastrointestinal tract, eye, heart, brain and salivary glands, and the implications for drugs used to treat OAB. The key factors that might determine the ideal antimuscarinic drug for treatment of OAB are also discussed. Further research is needed to show whether the M3 selective receptor antagonists have any advantage over less selective drugs, in leading to fewer adverse events.

Alzheimer's disease drugs promote neurogenesis

Alzheimer's disease (AD) is associated with increased production of new neurons (neurogenesis), which may be directed at brain repair. However, the effect of drugs used to treat AD on neurogenesis is unknown. We administered tacrine, galantamine or memantine to mouse cerebral cortical cultures in vitro, and to mice in vivo, and measured neurogenesis by labeling newborn cells with bromodeoxyuridine (BrdU) and confirming their neuronal lineage by cell-type-specific protein expression. All three drugs increased BrdU incorporation into cortical cultures in vitro by up to 40%, and increased BrdU labeling of cells in neuroproliferative regions of the adult mouse brain in vivo by 26-45%. BrdU labeling was associated with neuronal markers, such as Hu and betaIII tubulin. Thus, drugs used to treat AD increase cerebral neurogenesis both in vitro and in vivo, which may contribute to their therapeutic effects.

Anti-Parkinsonian agents have anti-amyloidogenic activity for Alzheimer's β-amyloid fibrils in vitro

Inhibition of the accumulation of amyloid beta-peptide (Abeta) and the formation of beta-amyloid fibrils (fAbeta) from Abeta, as well as the destabilization of preformed fAbeta in the central nervous system would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). Many studies have demonstrated that oxidative damage plays a central role in AD pathogenesis, as well as Parkinson disease (PD). Among the antioxidant strategies proposed, increasing evidence points to the possibility of achieving neuroprotection by dopamine agonists, as well as monoamine oxidase B (MAO-B) inhibitors. Actually, the beneficial effect of selegiline, a MAO-B inhibitor, in AD has been noted in several clinical studies. On the reverse, antimuscarinic agents have been reported to accelerate beta-amyloidosis and senile plaque formation in PD. Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of anti-Parkinsonian agents, dopamine, levodopa, pergolide, bromocriptine, selegiline, and trihexyphenidyl on the formation, extension, and destabilization of fAbeta(1-40) and fAbeta(1-42) at pH 7.5 at 37 degrees C in vitro. The anti-Parkinsonian agents other than trihexyphenidyl dose-dependently inhibited fAbeta formation from Abeta(1-40) and Abeta(1-42), as well as their extension. Moreover, these agents dose-dependently destabilized preformed fAbetas. The overall activity of the molecules examined was in the order of: dopamine>selegiline>levodopa=pergolide>bromocriptine. Although the exact mechanism of the anti-amyloidogenic activity of these agents is unclear, these and other structurally related compounds could be key molecules for the development of therapeutics for AD and other conformational diseases.

Antimuscarinic drugs for overactive bladder and their potential effects on cognitive function in older patients

Antimuscarinic agents are the predominant pharmacological treatment for patients with overactive bladder (OAB). These drugs are thought to act primarily through antagonism at muscarinic M3 receptors located at neuromuscular junctions in the human bladder detrusor muscle. Several of these drugs have been shown to be efficacious in ameliorating the symptoms of OAB in older patients, but most currently available agents lack selectivity for the M3 receptor subtype, and interaction with other muscarinic receptor subtypes throughout the body may adversely affect a variety of physiological functions and result in unwanted side effects, including cognitive dysfunction. With the recent availability of antimuscarinic agents that show increased selectivity for M3 receptors relative to other muscarinic subtypes, an invitational expert panel meeting was convened to review not only the mechanisms by which antimuscarinic agents could affect cognitive function, but also the published literature on cognitive adverse events. A review of the literature shows that the cholinergic system in the central nervous system (CNS) exerts a major influence on cognitive processes, in particular memory via M1 cholinergic receptors. In addition, recent evidence suggests a role for M2 receptors in mediating cognitive function. Thus, cognitive dysfunction (including memory loss) during treatment with nonselective antimuscarinic agents for OAB is of growing concern, particularly in older patients and those with mild cognitive impairment or dementia. Increased blood-brain barrier permeability, which can occur with advanced age and certain comorbidities, may also facilitate CNS access of antimuscarinic agents (regardless of their physiochemical properties) and add to antimuscarinic burden. On the basis of available evidence, antimuscarinic agents with selectivity for M3 over M1 and M2 receptors, limited CNS penetration, or both may therefore offer a favorable balance of efficacy in treating OAB together with a reduced risk of adverse cognitive events in the older population.

Management of Parkinson???s Disease Dementia

Parkinson's disease dementia (PDD) ultimately develops in about 80% of patients with Parkinson's disease (PD), and cross-sectional studies have found that some 30% of these patients will experience neuropsychiatric symptoms, such as visual hallucinations and psychosis. The most consistently reported risk factors for dementia in PD are age, severe parkinsonism and mild cognitive impairment. In PDD, both subcortical cognitive and cortical cognitive profiles are described. Specific disorders of sleep, such as rapid eye movement sleep behaviour disorder, excessive daytime sleepiness and sleep attacks, occur frequently. Alzheimer and Lewy body pathology coexist, but the Lewy body pathology in limbic and cortical areas seems to be the main cause of dementia. Neurochemical changes in the biogenic amines and acetylcholine are common, and magnetic resonance imaging studies have shown cortical atrophy in wide cortical areas, including the hippocampus. All PD patients should be screened for mild cognitive impairment and dementia. A large randomised clinical trial showed that the cholinesterase inhibitor rivastigmine has desirable effects on cognition and neuropsychiatric symptoms in PDD patients. Atypical antipsychotic agents may improve psychosis in PDD, but the evidence for this is poor and adverse effects from such therapy are common and may be severe. Non-pharmacological interventions can also be effective but require further study.

Methods for Assessing Drug-Related Anticholinergic Activity

The geriatric population is a large consumer of both prescription and over-the-counter drugs. Positive outcomes from drugs depend on the delicate interplay between therapeutic and adverse effects. This relationship becomes tortuous with simultaneous administration of several drugs. Numerous concomitant drug therapies may be essential for providing quality patient care but may also increase the possibility of an adverse drug event. Increasing sensitivity to drug effects in the geriatric population also creates concern over adverse effects. Drugs that possess anticholinergic properties are especially worrisome, as these properties may manifest as hazardous physiologic and psychological adverse drug events. Consequently, clinicians strive to minimize total drug exposure to agents possessing anticholinergic properties in elderly patients. A review of the literature revealed four methods that might help clinicians systematically reduce or eliminate potentially offending anticholinergic drugs. Each of the four has merits and limitations, with no ideal evidence-based approach used. Three of the four methods described have research utility; however, only one of the methods is clinically useful.

Psychiatric and behavioral symptoms in Alzheimer’s disease and other dementias: Etiology and management

Psychiatric and behavioral symptoms are common in all types of dementia and have important consequences for patients, caregivers, and society. This paper reviews recent studies of the etiology and management of these symptoms. Genetic and neurochemical studies indicate that cholinergic, serotonergic, and dopaminergic systems may influence the risk of psychiatric symptoms in patients with dementia. There is still no consensus regarding the management of such symptoms. Controlled studies of psychosocial interventions, usually performed in the nursing home setting, report encouraging results. Atypical antipsychotics may be effective in some cases but have a high risk of adverse events. There is emerging evidence that cholinesterase inhibitors may reduce and prevent such symptoms. More studies are needed to clarify the role of cholinergic and other psychotropic agents as well as nonpharmacologic interventions for psychiatric and behavioral symptoms in patients with dementia.

Attenuation of Abeta deposition in the entorhinal cortex of normal elderly individuals associated with tobacco smoking

Investigating correlates of tobacco smoking provides the only currently available opportunity of examining effects of long-term exposure of nicotinic receptors on a specific nicotinic agonist in human. Alzheimer-type pathology (Abeta and abnormally phosphorylated tau assessed on the basis of AT8 immunoreactivity) together with vascular markers has been compared in age-matched groups of normal elderly smokers and non-smokers in the entorhinal cortex, an area of noted age-related pathology. The density of total Abeta and diffuse Abeta immunoreactivity, together with formic acid-extractable Abeta42 but not Abeta40, was reduced in smokers (n = 10-18) compared with non-smokers (n = 10-20) (P < 0.05). There was also a reduced percentage of cortical and leptomeningeal vessels with associated Abeta immunoreactivity in smokers (n = 13) compared with non-smokers (n = 14) (P < 0.005 and 0.05, respectively). There was a significant inverse correlation between formic acid-extractable Abeta42 and pack years (n = 34, r = -0.389, P = 0.025), with a similar trend for total Abeta immunoreactivity which did not reach statistical significance (n = 30, r = -0.323, P = 0.082). In contrast, there were no significant group differences for vascular markers (collagen IV, alpha-actin or glucose transporter 1), AT8 immunoreactivity or phosphate-buffered saline-soluble Abeta peptides, and no significant associations with gender for any of the measured parameters. These findings are consistent with previously reported reductions in histologically assessed amyloid plaques in aged human brain associated with tobacco use and dramatic lessening of Abeta deposits in APPsw mice after nicotine treatment. Development of nicotinic drugs to protect against beta-amyloidosis as one of the principal pathological hallmarks of brain ageing and Alzheimer's disease is indicated.

The k variant of the butyrylcholinesterase gene is associated with reduced phosphorylation of tau in dementia patients

Accumulating evidence suggests that butyrylcholinesterase (BuChE) plays an important role in the progression of cognitive deficits and Alzheimer-type pathology in dementia patients. We examined the relationship between the K variant of BuChE and the severity of deposits of amyloid (Abeta(1-42)) and phosphorylated tau in the temporal cortex (BA36) of 30 prospectively studied autopsy-diagnosed dementia (Alzheimer's disease and dementia with Lewy bodies) patients. There was 42% less phosphorylated tau in BA36 in cases with > or =1 K compared with those with wild-type BuChE alleles (t = 2.2, p = 0.039), but no difference in the extent of Abeta(1-42) deposition. BuChE may play this role in the phosphorylation of tau, relevant to therapeutic inhibition of the enzyme.

Neuroleptics are associated with more severe tangle pathology in dementia with Lewy bodies

BACKGROUND

Neuroleptics are only modestly effective in dementia and associated with a range of adverse effects including cognitive decline. Effects of the drugs on molecular pathology in brain tissue from people with dementia have not been investigated.

OBJECTIVES

To compare the severity of Alzheimer type pathology in matched groups of people with dementia with Lewy bodies (DLB), treated and not treated with neuroleptics.

METHODS

The relationship between neuroleptics and Alzheimer-type pathology was determined in 40 (17 neuroleptic treated, 23 neuroleptic free, matched for age, disease duration and psychosis) clinically prospectively studied, autopsy diagnosed DLB patients.

RESULTS

In regression analyses, taking neuroleptics was significantly associated with increased neurofibrillary tangles but not amyloid plaques in cortical areas examined. The patient characteristics and the frequencies of key psychiatric symptoms were similar in the patients taking and not taking neuroleptics.

CONCLUSION

Although patients were not randomized and the results which are observed need to be interpreted cautiously, if substantiated, this is an important finding with major implications for the pharmacological management of DLB patients and highlights the need to determine the impact of neuroleptics upon tangle pathology in AD.

A pooled analysis of three phase III studies to investigate the efficacy, tolerability and safety of darifenacin, a muscarinic M3 selective receptor antagonist, in the treatment of overactive bladder

OBJECTIVE

To evaluate the efficacy, tolerability and safety of darifenacin, a muscarinic M3 selective receptor antagonist (M3 SRA), from an analysis of pooled data from three phase III, multicentre, double-blind clinical trials in patients with overactive bladder (OAB).

PATIENTS AND METHODS

After a 4-week washout/run-in period, 1059 adults (85% women) with symptoms of OAB (frequency and urgency with urge incontinence) for > or = 6 months were randomized to once-daily oral treatment with darifenacin (7.5 mg, 337; or 15 mg, 334) or matching placebo (388) for 12 weeks. Efficacy was evaluated using electronic patient diaries that recorded incontinence episodes (including those resulting in a change of clothing or pads), frequency and severity of urgency, voiding frequency, and bladder capacity (volume voided). Safety was evaluated by analysis of adverse events (AEs), withdrawal rates and laboratory tests.

RESULTS

Relative to baseline, 12 weeks of treatment with darifenacin resulted in a significant reduction in the median (% change, interquartile range) number of incontinence episodes per week; 7.5 mg (-8.8, -68.4%, -15.1 to -4.4); 15 mg; (-10.6, -76.8%, -17.3 to -5.8: both P < 0.01 vs placebo). There was a significant dose-response trend in each study for which darifenacin 7.5 and 15 mg were evaluated (P < 0.01). There were also significant decreases in the frequency and severity of urgency, voiding frequency, and number of significant leaks (incontinence episodes resulting in a change of clothing or pads; both P < or = 0.001 vs placebo), together with an increase in bladder capacity (both P < 0.01 vs placebo). Darifenacin was well tolerated; the most common AEs were dry mouth and constipation, although together these resulted in few discontinuations (darifenacin 7.5 mg 0.6% of patients; 15 mg 2.1%; placebo 0.3%). The incidence of peripheral/central nervous system and cardiovascular AEs were comparable with those on placebo.

CONCLUSIONS

Darifenacin (7.5 and 15 mg once daily) is effective in the treatment of patients with OAB. As predicted by its M3 selectivity and associated M1/M2-sparing profile, darifenacin was well tolerated with no central nervous system or cardiovascular safety concerns.

In vivo regulation of GSK3 phosphorylation by cholinergic and NMDA receptors

Glycogen synthase kinase-3 (GSK3), which is inhibited by serine-phosphorylation, is involved in the neuropathology of Alzheimer's disease (AD). We tested if the two therapeutic strategies used for AD, inhibition of acetylcholinesterase and of N-methyl-D-aspartate (NMDA) receptors, modulate the phosphorylation state of the two isoforms of GSK3 in mouse brain. Large, rapid increases in the levels of phospho-Ser21-GSK3alpha and phospho-Ser9-GSK3beta occurred in mouse hippocampus, cerebral cortex, and striatum after treatment of mice with the muscarinic agonist pilocarpine or the acetylcholinesterase inhibitor physostigmine. Treatment with memantine, an NMDA receptor antagonist, also increased the serine-phosphorylation of both GSK3 isoforms in mouse brain. Co-administration of physostigmine and memantine increased serine-phosphorylated GSK3 levels equally to that achieved by either agent alone, indicating that the actions of these two drugs converge on overlapping pools of GSK3. Thus, drugs in each class of therapeutic agents used for AD have the common property of increasing the regulatory serine-phosphorylation of GSK3 within common pools of the enzyme.

Quetiapine and rivastigmine and cognitive decline in Alzheimer's disease: randomised double blind placebo controlled trial

OBJECTIVES

To determine the respective efficacy of quetiapine and rivastigmine for agitation in people with dementia in institutional care and to evaluate these treatments with respect to change in cognitive performance.

DESIGN

Randomised double blind (clinician, patient, outcomes assessor) placebo controlled trial.

SETTING

Care facilities in the north east of England.

PARTICIPANTS

93 patients with Alzheimer's disease, dementia, and clinically significant agitation.

INTERVENTION

Atypical antipsychotic (quetiapine), cholinesterase inhibitor (rivastigmine), or placebo (double dummy).

MAIN OUTCOME MEASURES

Agitation (Cohen-Mansfield agitation inventory) and cognition (severe impairment battery) at baseline and at six weeks and 26 weeks. The primary outcome was agitation inventory at six weeks.

RESULTS

31 patients were randomised to each group, and 80 (86%) started treatment (25 rivastigmine, 26 quetiapine, 29 placebo), of whom 71 (89%) tolerated the maximum protocol dose (22 rivastigmine, 23 quetiapine, 26 placebo). Compared with placebo, neither group showed significant differences in improvement on the agitation inventory either at six weeks or 26 weeks. Fifty six patients scored > 10 on the severe impairment battery at baseline, 46 (82%) of whom were included in the analysis at six week follow up (14 rivastigmine, 14 quetiapine, 18 placebo). For quetiapine the change in severe impairment battery score from baseline was estimated as an average of -14.6 points (95% confidence interval -25.3 to -4.0) lower (that is, worse) than in the placebo group at six weeks (P = 0.009) and -15.4 points (-27.0 to -3.8) lower at 26 weeks (P = 0.01). The corresponding changes with rivastigmine were -3.5 points (-13.1 to 6.2) lower at six weeks (P = 0.5) and -7.5 points (-21.0 to 6.0) lower at 26 weeks (P = 0.3).

CONCLUSIONS

Neither quetiapine nor rivastigmine are effective in the treatment of agitation in people with dementia in institutional care. Compared with placebo, quetiapine is associated with significantly greater cognitive decline.

Cognitive performance in people with Parkinson's disease and mild or moderate depression: effects of dopamine agonists in an add-on to L-dopa therapy

In a randomized prospective multi-centre study, we evaluated the cognitive performances of a group of 41 non-demented patients, all with advanced Parkinson's disease (PD) and a current depressive episode, in whom the effects of pramipexole (PPX) and pergolide (PRG) in an add-on to l-dopa therapy were also studied and published with regard to motor symptoms of PD, motor complications and depression. The Trail Making Test, the Stroop test and four subtests (arithmetic, picture completion, digit symbols and similarities) of the Wechsler Adult Intelligence Scale-Revised were performed prior to and 8 months after the administration of either PPX or PRG. We found no statistically significant difference between the two tested drugs or between the first and the last visit in any of the above-listed neuropsychological tests. All patients' motor outcomes significantly improved and we conclusively demonstrated the anti-depressive effect of PPX. The dissociation of dopaminomimetic effects on the different tested domains indicates that there are different pathological mechanisms of cognitive, motor and affective disturbances in advanced PD patients. In our non-demented group of fluctuating depressed PD subjects, both PPX and PRG administration in combination with l-dopa were safe in terms of the effect on cognitive performance.

Confusion about measuring central nervous system effects

Anticholinergic therapy together with behavioral treatment are the main stays of treatment for the overactive bladder. Successful therapy and patient compliance depend very much on side effects. In the past, little attention has been paid to anticholinergic side effects in the central nervous system (CNS), which can be critical, especially for elderly patients. Incidence and intensity of CNS effects depend on the pharmacokinetic and pharmacodynamic properties that are decisive whether anticholinergics pass the blood-brain barrier as a result of passive and active transport mechanisms. To measure potential CNS side effects of anticholinergic drugs, rapid eye movement sleep analysis, quantitative-topographic electroencephalogram studies, and psychometric tests were performed. Structural changes in brain morphology resulting from anticholinergics also were analyzed in a post-mortem study.

Evidence-based medical review update: Pharmacological and surgical treatments of Parkinson's disease: 2001 to 2004

The objective of this study is to update a previous evidence-based medicine (EBM) review on Parkinson's disease (PD) treatments, adding January 2001 to January 2004 information. The Movement Disorder Society (MDS) Task Force prepared an EBM review of PD treatments covering data up to January 2001. The authors reviewed Level I (randomized clinical trials) reports of pharmacological and surgical interventions for PD, published as full articles in English (January 2001-January 2004). Inclusion criteria and ranking followed the original program and adhered to EBM methodology. For Efficacy Conclusions, treatments were designated Efficacious, Likely Efficacious, Non-Efficacious, or Insufficient Data. Four clinical indications were considered for each intervention: prevention of disease progression; treatment of Parkinsonism, as monotherapy and as adjuncts to levodopa where indicated; prevention of motor complications; treatment of motor complications. Twenty-seven new studies qualified for efficacy review, and others covered new safety issues. Apomorphine, piribedil, unilateral pallidotomy, and subthalamic nucleus stimulation moved upward in efficacy ratings. Rasagiline, was newly rated as Efficacious monotherapy for control of Parkinsonism. New Level I data moved human fetal nigral transplants, as performed to date, from Insufficient Data to Non- efficacious for the treatment of Parkinsonism, motor fluctuations, and dyskinesias. Selegiline was reassigned as Non-efficacious for the prevention of dyskinesias. Other designations did not change. In a field as active in clinical trials as PD, frequent updating of therapy-based reviews is essential. We consider a 3-year period a reasonable time frame for published updates and are working to establish a Web-based mechanism to update the report in an ongoing manner.

Role of cholinesterase inhibitors in Parkinson's disease and dementia with Lewy bodies

This article reviews the cholinergic changes in Parkinson's disease and dementia (PDD) and dementia with Lewy bodies (DLB), their potential clinical implications, and the available evidence for cholinesterase inhibitors in the treatment of PDD and DLB. Marked neuronal loss of cholinergic nuclei, reduced cholinergic markers in the neocortex, hippocampus, and selected thalamic nuclei, and receptor changes have been reported. One large and 2 small placebo-controlled trials and nearly 20 open-label studies suggest that cholinesterase inhibitors have a positive effect on cognition, psychiatric symptoms, and global function in patients with DLB and PDD. The treatment is well tolerated in most patients without any apparent worsening of extrapyramidal motor features. Given the high risk of severe sensitivity reactions and increased risk of cerebrovascular incidents during treatment with neuroleptics, more clinical trials of cholinesterase inhibitors are encouraged to establish their precise role in DLB and PDD.

Neuropsychiatric complications of medical and surgical therapies for Parkinson's disease

This review deals with the range of neuropsychiatric problems that may arise from the use of medical and surgical therapies in the treatment of Parkinson's disease. As new approaches emerge, these problems are diversifying. Well-recognized drug-related complications include hallucinations and psychosis and the so-called dopamine-dysregulation syndrome. The etiology of these problems has not been fully established and is not clearly dose related, while the management can be difficult and needs to be tailored to the individual patient. Cholinergic and dopaminergic drugs may both influence cognitive function. The development of pharmacogenetics could improve the therapeutic ratio of medical approaches to PD in the future. The literature relating to the neuropsychiatric issues complicating the surgical treatment of Parkinson's disease is more recent and frequently suffers from methodological problems, lack of a systematic approach, and adequate patient follow-up. The emergence of neuropsychiatric problems in association with surgery has shed new light upon the pathophysiological mechanisms underpinning these symptoms. Depression, hypomania, euphoria, mirth, and hypersexuality have all been described following deep brain stimulation procedures, although most studies have concentrated upon the depressive features. Anxiety has been described only rarely to date. Fortunately, permanent cognitive complications appear to be rare. The optimal management approach for surgically related neuropsychiatric problems is unknown at present. Prospective multicenter studies would contribute significantly to resolving this therapeutic uncertainty.

Dementia in Parkinson's disease: cause and treatment

PURPOSE OF REVIEW

Dementia in Parkinson's disease is increasingly being recognized. A number of studies have recently appeared on the epidemiology, clinical features, pathological correlations and treatment of dementia in Parkinson's disease. The purpose of this article is to provide an overview of recent findings on dementia associated with Parkinson's disease, from February 2003 to the present.

RECENT FINDINGS

The cumulative prevalence of dementia in Parkinson's disease can be as high as 78%; dementia is especially prevalent in older patients. The profile of dementia seems to be different from that of Alzheimer's disease and similar to that of dementia with Lewy bodies. Clinicopathological correlation studies have suggested that dementia correlates best with Lewy bodies in certain limbic and cortical areas, but not all patients with sufficient Lewy bodies for a pathological diagnosis of dementia with Lewy bodies are demented. Cholinergic deficits in the cerebral cortex can be shown with in-vivo imaging studies, and seem to be more severe than in Alzheimer's disease. Several small studies with three different cholinesterase inhibitors suggest that these drugs can be effective in the treatment of PD dementia.

SUMMARY

Dementia is highly prevalent in Parkinson's disease. The prototype of dementia in Parkinson's disease is a dysexecutive syndrome with impaired attention, executive functions and secondarily impaired memory. Neurochemically the most significant deficit seems to be cholinergic; dementia seems to correlate best with cortical and limbic Lewy bodies. Preliminary evidence suggests that cholinesterase inhibitors may be effective in Parkinson's disease dementia, and the results of large-scale, randomized and controlled studies are awaited to confirm these findings.

Cerebral amyloid angiopathy plays a direct role in the pathogenesis of Alzheimer’s disease

For the purposes of this debate here we argue the case that cerebral amyloid angiopathy (CAA) has a direct role in the pathogenesis of Alzheimer's disease (AD). Firstly, there is a very close relationship between CAA and AD and they share genetic risk factors. Secondly, we propose a specific mechanism which puts age-related cerebrovascular degeneration at a crucial point in the pathogenesis of AD as follows. Amyloid beta-protein (Abeta) is normally eliminated from the brain along with extracellular fluid by bulk flow along the perivascular pathway. Age-related fibrosis of cerebral cortical and meningeal arteries leads to impaired drainage of Abeta along the perivascular pathway and, together with the production of Abeta by smooth muscle cells and perivascular cells, is responsible for accumulation of Abeta as CAA. Reduced elimination leads to increased concentration of soluble Abeta in the extracellular fluid of the brain parenchyma. Increased concentration of soluble Abeta leads to the formation of insoluble Abeta plaques, other features of AD pathology, and dementia.

The Cholinergic Lesion of Alzheimer's Disease: Pivotal Factor or Side Show?

A profound loss of cortical cholinergic innervation is a nearly invariant feature of advanced Alzheimer's disease (AD). The temporal course of this lesion and its relationship to other aspects of the disease have not yet been fully clarified. Despite assertions to the contrary, a review of the evidence suggests that a perturbation of cholinergic innervation is likely to be present even in the very early stages of AD. This cholinergic lesion is unlikely to be a major determinant of the clinical symptoms or of the neuropathological lesions. Nonetheless, it almost certainly contributes to the severity of the cognitive and behavioral deficits, especially in the areas of memory and attention. The cholinergic lesion may also influence the progression of the neuropathological process through complex interactions with amyloidogenesis, tau phosphorylation and neuroplasticity.