Use of rivastigmine or galantamine and risk of adverse cardiac events: a database study from the Netherlands

Galantamine-Induced Third-Degree Heart Block

Galantamine is commonly used to manage symptoms of Alzheimer's disease and other cognitive disorders. While it is generally well-tolerated, cardiovascular side effects are rare but can be serious. We report the case of a patient who developed a third-degree heart block after initiating galantamine therapy. This case highlights the importance of monitoring patients for cardiac adverse effects when using galantamine and the need for prompt intervention when such effects occur.

Alzheimer's disease medication and risk of all-cause mortality and all-cause hospitalization: A retrospective cohort study

Introduction

Identifying Alzheimer's disease (AD) pharmacologic treatment options that effectively reduce the risk of mortality and hospitalization in real-world settings is critical.

Methods

We compared donepezil, galantamine, memantine, oral rivastigmine, and transdermal rivastigmine with regard to all-cause mortality and all-cause hospitalization risk among fee-for-service Medicare beneficiaries with AD (aged ≥ 65 years) using a retrospective cohort study design. Our primary analysis was based on intention to treat (ITT), but we also present as-treated analysis.

Results

In our final study sample (N = 21,558), significant difference in survival among index AD medication groups were observed with donepezil being associated with better survival than memantine, and oral and transdermal forms of rivastigmine for both ITT and as-treated analysis. Difference in hazards of all-cause hospitalization among index AD medication groups was observed in ITT analysis but not in as-treated analysis.

Discussion

Significant differences exist in terms of mortality and hospitalization risk with different AD medication initiation in real-world setting.

Large-Scale Predictive Drug Safety: From Structural Alerts to Biological Mechanisms

The recent explosion of data linking drugs, proteins, and pathways with safety events has promoted the development of integrative systems approaches to large-scale predictive drug safety. The added value of such approaches is that, beyond the traditional identification of potentially labile chemical fragments for selected toxicity end points, they have the potential to provide mechanistic insights for a much larger and diverse set of safety events in a statistically sound nonsupervised manner, based on the similarity to drug classes, the interaction with secondary targets, and the interference with biological pathways. The combined identification of chemical and biological hazards enhances our ability to assess the safety risk of bioactive small molecules with higher confidence than that using structural alerts only. We are still a very long way from reliably predicting drug safety, but advances toward gaining a better understanding of the mechanisms leading to adverse outcomes represent a step forward in this direction.

Adverse Drug Reactions Reported With Cholinesterase Inhibitors

Background: No worldwide pharmacovigilance study evaluating the spectrum of adverse drug reactions (ADRs) induced by cholinesterase inhibitors (ChEI) in Alzheimer’s disease has been conducted since their emergence on the market. Objective: To describe ChEI related ADRs in Alzheimer’s disease (donepezil, rivastigmine, and galantamine) and characterize their seriousness as reported by national pharmacovigilance systems to VigiBase, a World Health Organization International Drug Monitoring Program database, between 1998 and 2013. Methods: All ChEI related reports, submitted to VigiBase between 1998 and 2013 from the five continents were extracted. Analyses were carried out for general, serious, and nonserious ADRs. Results: A total of 18 955 reports (43 753 ADRs) from 58 countries were reported: 60.1% in women; mean age 77.4 ± 9.1 years. Most reports originated from Europe (47.6%) and North America (40.4%). Rivastigmine and donepezil were involved in most reports (41.4% each). The most frequently reported ADRs were neuropsychiatric (31.4%), gastrointestinal (15.9%), general (11.9%), and cardiovascular (11.7%) disorders. During the 2006-2013 period, serious ADRs remained more often reported than nonserious ones; the most serious were neuropsychiatric (34.0%), general (14.0%), cardiovascular (12.1%), and gastrointestinal (11.6%) disorders. Medication errors were reported in 2.0% of serious cases. Death occurred in 2.3% of the reports. Conclusions: This international pharmacovigilance study highlights the ADR pattern induced by ChEIs. Neuropsychiatric events were the most frequently reported ADRs. Serious cardiovascular events were frequently reported, suggesting that their significance has probably been previously underestimated. Given the frailty of the patients and the frequent comedications, caution is advised before introducing a ChEI.

The influence of cholinesterase inhibitor therapy for dementia on risk of cardiac pacemaker insertion: a retrospective, population-based, health administrative databases study in Ontario, Canada

BACKGROUND

Cholinesterase inhibitors are used to treat the symptoms of dementia and can theoretically cause bradycardia. Previous studies suggest that patients taking these medications have an increased risk of undergoing pacemaker insertion. Since these drugs have a marginal impact on patient outcomes, it might be preferable to change drug treatment rather than implant a pacemaker. This population-based study determined the association of people with dementia exposed to cholinesterase inhibitor medication and pacemaker insertion.

METHODS

We used data from the Ontario health administrative databases from January 1, 1993 to June 30, 2012. We included all community-dwelling seniors who had a code for dementia and were exposed to cholinesterase inhibitors (donezepil, galantamine, and rivastigmine) and/or drugs used to treat co-morbidities of hypertension, diabetes, depression and hypothyroidism. We controlled for exposure to anti-arrhythmic drugs. Observation started at first exposure to any medication and continued until the earliest of pacemaker insertion, death, or end of study.

RESULTS

2,353,909 people were included with 96,000 (4.1%) undergoing pacemaker insertion during the observation period. Case-control analysis showed that pacemaker patients were less likely to be coded with dementia (unadjusted OR 0.42 [95%CI 0.41-0.42]) or exposed to cholinesterase inhibitors (unadjusted OR 0.39 [95%CI 0.37-0.41]). That Cohort analysis showed patients with dementia taking cholinesterase inhibitors had a decreased risk of pacemaker insertion (unadj-HR 0.58 [0.55-0.61]). Adjustment for patient age, sex, and other medications did not notably change results, as did restricting the analysis to incident users.

CONCLUSIONS

Patients taking cholinesterase inhibitors rarely undergo, and have a significantly reduced risk of, cardiac pacemaker insertion.

Cardioprotection and anticholinesterases in patients with Alzheimer's disease: time for reappraisal

Background/Aim

Traditional risk factors, like impaired transmitral flow in diastolic filling [vortex formation time (VFT) as echocardiographic parameter], contribute to Alzheimer's disease (AD). Moreover, we observed that acetylcholinesterase inhibitors provide a significant cardioprotection. We assessed the pathogenetic role of VFT as early cardiovascular risk factor in 23 AD patients and 24 controls.

Results

The results showed no statistical difference between the two groups, but the VFT values were significantly lower in nontreated AD patients, and higher value were observed in AD patients treated with anticholinesterases.

Conclusions

The results support the beneficial effects of anticholinesterases on the cardiovascular system of AD patients. Thus, the transition to evidence-based medicine and an in vivo model of cardiomyocytes might strengthen these results.

In silico QSAR analysis of quercetin reveals its potential as therapeutic drug for Alzheimer's disease

Acetylcholine-esterase (AchE) inhibitors are one of the most potent drug molecules against Alzheimer's disease (AD). But, patients treated with current AchE inhibitors often experience severe side effects. Quercetin is a plant flavonoid compound which can act as AchE inhibitor and it may be a better alternative to current AchE inhibitors in terms of effectiveness with no or fewer side effects.

AIMS

The aim of the study was to compare quercetin with conventional AchE inhibitors to search for a better drug candidate.

METHODS AND MATERIALS

Physico-chemical properties of conventional drugs and quercetin were predicted using bioinformatics tools. Molecular docking of these compounds on the active site of AchE was performed using AutoDock and comparative analysis was performed. Later, modification on the basic structure of quercetin with different functional groups was done to perform QSAR analysis.

RESULT AND DISCUSSION

Quercetin showed a similar drug likeness score to the conventional drugs. The binding strength for quercetin in the active site of the enzyme was -8.8 kcal/mol, which was considerably higher than binding scores for some of the drugs such as donepezil (binding score -7.9 kcal/mol). Fifteen hydrogen bonds were predicted between quercetin and the enzyme whereas conventional drugs had fewer or even no hydrogen bonds. It implies that quercetin can act as a better inhibitor than conventional drugs. To find out even better inhibitor, similar structures of quercetin were searched through SIMCOMP database and a methylation in the 4-OH position of the molecule showed better binding affinity than parent quercetin. Quantitative structure activity relationship study indicated that O-4 methylation was specifically responsible for better affinity.

CONCLUSION

This in silico study has conclusively predicted the superiority of the natural compound quercetin over the conventional drugs as AchE inhibitor and it sets the need for further in-vitro study of this compound in future.