Donepezil-induced adverse side effects of cardiac rhythm: 2 cases report of atrioventricular block and Torsade de Pointes

Effects of Cholinesterase Inhibitor Medication on QTc Interval in Memory Clinic Patients

BACKGROUND

Cholinesterase inhibitors (ChEIs)-donepezil, rivastigmine, and galantamine-are beneficial in treating Alzheimer disease (AD). However, due to their impact on extra-cerebral acetylcholine signaling, concerns about cardiac adverse effects, including QT interval prolongation, persist. Despite this, evidence-based guidelines for electrocardiogram (ECG) monitoring during ChEI treatment are lacking, and prior studies on ChEIs and corrected QT intervals (QTc) yield inconsistent findings.

OBJECTIVE

This study aimed to investigate the association between ChEI use and changes in QTc intervals among older adults.

METHODS

We collected retrospective data from first-time visitors to the geriatric memory clinic of Turku City Hospital in 2017 and 2019. We included patients who were newly prescribed ChEIs and had ECG data available (n = 126, mean age 81.1 years, 56.3% female). QTc prolongation was defined as ≥460 ms in females and ≥450 ms in men. Paired t tests compared QTc means before and during ChEI use, and McNemar tests analyzed changes in the proportion of prolonged QTc.

RESULTS

Mean ± SD QTc (ms) before versus during ChEI use was: 420.8 ± 24.0 versus 423.9 ± 28.0 (P = .13) for donepezil; 416.0 ± 20.4 versus 416.5 ± 26.1 (P = .92) for galantamine; 416.1 ± 22.3 versus 409.6 ± 20.1 (P = .30) for rivastigmine; and 419.7 ± 23.4 versus 421.5 ± 27.3 (P = .34) for all ChEIs. Prolonged QTc occurred in 7.9% of patients before versus 12.7% during ChEI use (P = .21).

CONCLUSION AND RELEVANCE

We found no statistically significant association between ChEI use and QTc interval prolongation or an increased proportion of pathological QTc values during ChEI treatment. Larger studies are warranted to establish evidence-based recommendations on ECG monitoring during ChEI medication.

Donepezil and Memantine-Induced Second-Degree Atrioventricular Block: A Case Report

Donepezil and memantine are second-generation antipsychotics widely used in the management of mild to moderate Alzheimer's disease. These drugs are highly selective for the central nervous system, targeting different neural pathways to mitigate cognitive decline. Donepezil is a reversible and specific acetylcholinesterase inhibitor, while memantine is an NMDA receptor antagonist which modulates glutamatergic activity. Although these medications are safe, they are associated with adverse effects, and cardiovascular complications are rare. The reported cardiac adverse drug reactions include bradycardia, atrioventricular block, and prolonged QT interval. We are reporting a case of an 81-year-old male patient with schizophrenia, Alzheimer's disease and bilateral sensorineural deafness receiving oral donepezil and memantine presented with second-degree atrioventricular block. The patient's atrioventricular block recovered completely in 2 to 3 weeks after the discontinuation of donepezil-memantine and with a short course of sympathomimetic drugs.

Proarrhythmic major adverse cardiac events with donepezil: A systematic review with meta-analysis

BACKGROUND

Cholinesterase inhibitors (ChEIs) are regularly used in Alzheimer's disease. Of the three ChEIs approved for dementia, donepezil is among the most prescribed drugs in the United States with nearly 6 million prescriptions in 2020; however, it is classified as a "known risk" QT interval-prolonging medication (QTPmed). Given this claim is derived from observational data including single case reports, we aimed to evaluate high-quality literature on the frequency and nature of proarrhythmic major adverse cardiac events (MACE) associated with donepezil.

METHODS

We searched Medline, Embase, International Pharmaceutical Abstracts, and Cochrane Central from 1996 onwards for randomized controlled trials (RCTs) involving patients age ≥18 years comparing donepezil to placebo. The MACE composite included mortality, sudden cardiac death, non-fatal cardiac arrest, Torsades de pointes, ventricular tachyarrhythmia, seizure or syncope. Random-effects meta-analyses were performed with a treatment-arm continuity correction for single and double zero event studies.

RESULTS

Sixty RCTs (n = 12,463) were included. Twenty-five of 60 trials (n = 5886) investigated participants with Alzheimer's disease and 33 trials monitored electrocardiogram data. The mean follow-up duration was 31 weeks (SD = 36). Mortality was the most commonly reported MACE (252/331, 75.8% events), the remainder were syncope or seizures, with no arrhythmia events. There was no increased risk of MACE with exposure to donepezil compared to placebo (risk ratio [RR] 1.08, 95% CI 0.88-1.33, I2 = 0%) and this was consistent in the subgroup analysis of trials including participants with cardiovascular morbidities (RR 1.14, 95% CI 0.88-1.47). Subgroup analysis suggested a trend toward more events with donepezil with follow-up ≥52 weeks (RR: 1.32, 0.98-1.79).

CONCLUSIONS

This systematic review with meta-analysis found donepezil may not be arrhythmogenic. Donepezil was not associated with mortality, ventricular arrhythmias, seizure or syncope, although longer durations of therapy need more study. Further research to clarify actual clinical outcomes related to QTPmed is important to inform prescribing practices.

Cholinesterase inhibitors-associated torsade de pointes/QT prolongation: a real-world pharmacovigilance study

Objective: Cholinesterase inhibitor (ChEIs) is the first-line drug for Alzheimer's disease (AD). Understanding torsade de pointes (TdP)/QT prolongation with different ChEIs is essential for its safe and rational administration. This study aimed to evaluate the correlation between different ChEIs and TdP/QT prolongation. Methods: All ChEIs related TdP/QT prolongation cases were retrieved from the FAERS database using standard MedDRA query (SMQ) from the first quarter of 2004 to the third quarter of 2022. Disproportionality and sensitivity analysis were used to determine the signal of TdP/QT prolongation related to ChEIs. Results: 557 cases of TdP/QT prolongation related to 3 ChEIs were searched by SMQ. The patients were mostly elderly people, with markedly more female than male. The signals of TdP/QT prolongation for ChEIs were detected by disproportionality analysis, and the signal of Donepezil was the strongest. The sensitivity analysis results indicate a robust and stable correlation between these signals with ChEIs. TdP/QT prolongation usually occurs within 1 month after taking ChEIs. The drug with the highest frequency of combination with donepezil and galantamine is citalopram, and the drug with the highest frequency of combination with rivastigmine is atorvastatin. Conclusion: The signals of TdP/QT prolongation related to ChEIs were strong and stable. It is necessary to be vigilant about the TdP/QT prolongation of various ChEIs, especially in elderly women, the initial stage after taking ChEIs, and when ChEIs combining with drugs that could prolong the QT interval.

Distribution of donepezil in postmortem casework

Donepezil is one of the primary treatments options for patients suffering from Alzheimer's Disease. In a review of more than 2200 postmortem donepezil positive blood specimens, 76% of concentrations were higher than the proposed therapeutic range. Means and medians were similar between central blood specimens and peripheral specimens, indicating minimal postmortem redistribution. Postmortem concentrations may not reflect those circulating antemortem. Mean and median postmortem blood concentrations were approximately 3-fold higher than those in antemortem blood specimens. Additionally, in cases where antemortem blood was available for testing, large increases in donepezil concentrations were reported between antemortem and postmortem specimens without documented administration by medical personnel. Elevated blood donepezil concentrations have been reported in multiple postmortem cases where cause of death was unrelated. The blood concentrations reported in cases where donepezil did not contribute to death overlapped with those in suspected drug overdose cases where other drugs may have been present. In 4 out of 5 suspected donepezil overdose cases, blood concentrations greater than 1000 ng/mL were reported, whereas less than 1% of all postmortem blood samples reviewed achieved these concentrations. Blood concentrations greater than 1000 ng/mL should be considered contributory when a drug overdose is suspected. Postmortem donepezil concentrations should be interpreted with caution in the context of a comprehensive case history.

Pharmacokinetic/Pharmacodynamic Models of an Alzheimer's Drug, Donepezil, in Rats

To investigate the relationship between the pharmacokinetics (PK) and pharmacodynamics (PD) of donepezil (Don), simultaneous examination of the PK of Don and the change in acetylcholine (ACh) in the cerebral hippocampus was analyzed using microdialysis in rats. Don plasma concentrations reached their maximum at the end of a 30-minute infusion. The maximum plasma concentrations (Cmaxs) of the major active metabolite, 6-O-desmethyl donepezil, were 9.38 and 13.3 ng/ml at 60 minutes after starting infusions at 1.25 and 2.5 mg/kg doses, respectively. The amount of ACh in the brain increased shortly after the start of the infusion and reached the maximum value at about 30 to 45 minutes, then decreased to the baseline with a slight delay from the transition of the Don concentration in plasma at a 2.5 mg/kg dose. However, the 1.25 mg/kg group showed little increase in ACh in the brain. The PK/PD models of Don, which were constructed using a general 2-compartment PK model with/without Michaelis-Menten metabolism and the suppressive effect of conversion of ACh to choline using an ordinary indirect response model, were able to effectively simulate Don's plasma and ACh profiles. The ACh profile in the cerebral hippocampus at a 1.25 mg/kg dose was effectively simulated using both constructed PK/PD models and parameters obtained at a 2.5 mg/kg dose by the PK/PD models and indicated that Don largely had no effect on ACh. When these models were used to simulate at 5 mg/kg, the Don PK were nearly linear, whereas the ACh transition had a different profile to lower doses. SIGNIFICANCE STATEMENT: Efficacy/safety of a drug and its pharmacokinetics (PK) are closely correlated. Therefore, it is important to understand the relationship between the drug's PK and its pharmacodynamics (PD). A quantitative procedure of achieving these goals is the PK/PD analysis. We constructed the PK/PD models of donepezil in rats. These models can predict the acetylcholine-time profiles from the PK. The modeling technique is a potential therapeutic application to predict the effect when changes in the PK are caused by pathological condition and co-administered drugs.

Alzheimer's disease therapy based on acetylcholinesterase inhibitor/blocker effects on voltage-gated potassium channels

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder with progressive loss of memory and other cognitive functions. The pathogenesis of this disease is complex and multifactorial, and remains obscure until now. To enhance the declined level of acetylcholine (ACh) resulting from loss of cholinergic neurons, acetylcholinesterase (AChE) inhibitors are developed and successfully approved for AD treatment in the clinic, with a limited therapeutic effectiveness. At present, it is generally accepted that multi-target strategy is potently useful for designing novel drugs for AD. Accumulated evidence reveals that Kv channels, which are broadly expressed in brain and possess crucial functions in modulating the neuronal activity, are inhibited by several acetylcholinesterase (AChE) inhibitors, such as tacrine, bis(7)-tacrine, donepezil and galantamine. Inhibition of Kv channels by these AChE inhibitors can generate neuroprotective effects by either mitigating Aβ toxicity and neuronal apoptosis, or facilitating cell proliferation. These inhibitory effects provide additional explanations for clinical beneficial effectiveness of AChE inhibitors, meaning that Kv channel is a promising candidate target for novel drugs for AD therapy.

Adverse Drug Reactions of Acetylcholinesterase Inhibitors in Older People Living with Dementia: A Comprehensive Literature Review

The rising of global geriatric population has contributed to increased prevalence of dementia. Dementia is a neurodegenerative disease, which is characterized by progressive deterioration of cognitive functions, such as judgment, language, memory, attention and visuospatial ability. Dementia not only has profoundly devastating physical and psychological health outcomes, but it also poses a considerable healthcare expenditure and burdens. Acetylcholinesterase inhibitors (AChEIs), or so-called anti-dementia medications, have been developed to delay the progression of neurocognitive disorders and to decrease healthcare needs. AChEIs have been widely prescribed in clinical practice for the treatment of Alzheimer's disease, which account for 70% of dementia. The rising use of AChEIs results in increased adverse drug reactions (ADRs) such as cardiovascular and gastrointestinal adverse effects, resulting from overstimulation of peripheral cholinergic activity and muscarinic receptor activation. Changes in pharmacokinetics (PK), pharmacodynamics (PD) and pharmacogenetics (PGx), and occurrence of drug interactions are said to be major risk factors of ADRs of AChEIs in this population. To date, comprehensive reviews in ADRs of AChEIs have so far been scarcely studied. Therefore, we aimed to recapitulate and update the diverse aspects of AChEIs, including the mechanisms of action, characteristics and risk factors of ADRs, and preventive strategies of their ADRs. The collation of this knowledge is essential to facilitate efforts to reduce ADRs of AChEIs.

In Vitro Metabolism of Donepezil in Liver Microsomes Using Non-Targeted Metabolomics

Donepezil is a reversible acetylcholinesterase inhibitor that is currently the most commonly prescribed drug for the treatment of Alzheimer’s disease. In general, donepezil is known as a safe and well-tolerated drug, and it was not associated with liver abnormalities in several clinical trials. However, rare cases of drug-related liver toxicity have been reported since it has become commercially available. Few studies have investigated the metabolic profile of donepezil, and the mechanism of liver damage caused by donepezil has not been elucidated. In this study, the in vitro metabolism of donepezil was investigated using liquid chromatography–tandem mass spectrometry based on a non-targeted metabolomics approach. To identify metabolites, the data were subjected to multivariate data analysis and molecular networking. A total of 21 donepezil metabolites (17 in human liver microsomes, 21 in mice liver microsomes, and 17 in rat liver microsomes) were detected including 14 newly identified metabolites. One potential reactive metabolite was identified in rat liver microsomal incubation samples. Metabolites were formed through four major metabolic pathways: (1) O-demethylation, (2) hydroxylation, (3) N-oxidation, and (4) N-debenzylation. This study indicates that a non-targeted metabolomics approach combined with molecular networking is a reliable tool to identify and detect unknown drug metabolites.

[Pharmacokinetics/Pharmacodynamic Analysis to Link Pharmacokinetics to Efficacy and Drug Interaction of Alzheimer's Disease Drugs]

In recent years, the number of patients with Alzheimer's type dementia continues to increase year by year. As a first-line drug, cholinesterase inhibitor is used. There is a close relationship between the time course of the drug plasma concentration (pharmacokinetics; PK) and the time course of its effects and side effects (pharmacodynamics; PD). However, the relationship between PK and PD is not simply that plasma concentrations are proportional to the effects. The effect is expressed through the characteristics of various pharmacokinetic processes. Therefore, it is important to investigate the transition of effects accompanying its pharmacokinetics. We conducted a fundamental PK/PD analysis using donepezil. Time course of acetylcholine in the hippocampus was investigated with relation to its PK after donepezil administration using rats. The PK and PD characteristics of the drug, including its active metabolite, were investigated. Additionally, Alzheimer's type dementia drugs are often given in combination with antiplatelet drugs such as cilostazol. It is reported that donepezil and cilostazol interact clinically, partly due to inhibition in the efflux transporters in certain tissues. There are various transporters in the body, and interactions through them may cause unexpected changes in the effects. So, it is important to calculate the correlation between the donepezil level in plasma and tissues after their combined administration. From the PK/PD point of view, the results of this study will provide insight into the time course of effects and the characteristics of drug-drug interaction in clinical practice.

Effect of QT Prolongation in Patients Taking Cholinesterase Inhibitors (Donepezil) for Alzheimer's Disease

Background: Cholinesterase inhibitors such as donepezil are used in the treatment of Alzheimer’s disease. Patients taking cholinesterase inhibitors can develop cholinergically mediated QT prolongation, which may lead to life-threatening arrhythmias. In this study we investigated the corrected QT interval (QTc) of patients taking donepezil.

Methods and Results: This study enrolled 114 outpatients attending Tarumizu Chuo Hospital. Subjects were divided into a donepezil group (n=57) or an age- and sex-matched control group (n=57). Physical findings, laboratory data, and electrocardiographic parameters were compared between the groups. QTc was significantly prolonged (mean [±SD] 0.443±0.032 s vs. 0.426±0.026s; P<0.001) and the percentage of patients with prolonged QTc was significantly higher (30% vs. 9%; P<0.01) in the donepezil than control group. Furthermore, in the donepezil group, QTc was significantly prolonged after patients started taking donepezil compared with baseline (from 0.433±0.034 to 0.442±0.033s; n=46; P<0.05). On univariate analysis, QTc was significantly associated with taking donepezil, as well as with hemoglobin, serum calcium concentration, and estimated glomerular filtration rate (eGFR; all P<0.01). On multivariate analysis, QTc was significantly associated with taking donepezil (P<0.001), serum potassium concentration (P<0.05), and eGFR (P<0.05).

Conclusions: The incidence of QTc prolongation was more frequent in patients taking donepezil than in the control group, and was difficult to predict. Periodic electrocardiogram examinations are recommended considering the possibility of adverse events, such as fatal arrhythmias.

QTc Interval Prolongation with Therapies Used to Treat Patients with Parkinson's Disease Psychosis: A Narrative Review

In addition to the classic motor symptoms of Parkinson's disease (PD), people with PD frequently experience nonmotor symptoms that can include autonomic dysfunction and neuropsychiatric symptoms such as PD psychosis (PDP). Common patient characteristics, including older age, use of multiple medications, and arrhythmias, are associated with increased risk of corrected QT interval (QTc) prolongation, and treatments for PDP (antipsychotics, dementia medications) may further increase this risk. This review evaluates how medications used to treat PDP affect QTc interval from literature indexed in the PubMed and Embase databases. Although not indicated for the treatment of psychosis, dementia therapies such as donepezil, rivastigmine, memantine, and galantamine are often used with or without antipsychotics and have minimal effects on QTc interval. Among the antipsychotics, data suggesting clinically meaningful QTc interval prolongation are limited. However, many antipsychotics have other safety concerns. Aripiprazole, olanzapine, and risperidone negatively affect motor function and are not recommended for PDP. Quetiapine is often sedating, can exacerbate underlying neurogenic orthostatic hypotension, and may prolong the QTc interval. Pimavanserin was approved by the US Food and Drug Administration (FDA) in 2016 and remains the only FDA-approved medication available to treat hallucinations and delusions associated with PDP. However, pimavanserin can increase QTc interval by approximately 5-8 ms. The potential for QTc prolongation should be considered in patients with symptomatic cardiac arrhythmias and those receiving QT-prolonging medications. In choosing a medication to treat PDP, expected efficacy must be balanced with potential safety concerns for individual patients.

Suspected donepezil toxicity: A case report

Donepezil toxicity can present similarly to beta-blocker overdose and colitis. Symptoms include confusion, diaphoresis, and bradycardia. In patients with suspected medication-related toxicities, it is important to consider all possible causative agents in the active medication list.

[Practical aspects of using donepezil in the treatment of dementia]

Donepezil is the most commonly used drug of the group of cholinesterase inhibitors. It is recommended for tretament of Alzheimer's disease. Donepezil is also used to treat dementia in Lewy body disease, Parkinson's disease with dementia, and vascular dementia. In Russia, donepezil is not used as often, which is facilitated by the concern of doctors about the possibility of serious side-effects. Clinical studies demonstrate the safety and good tolerability of donepezil. Our study included 62 patients with dementia due to various neurodegenerative diseases (Alzheimer's disease, Lewy body disease, Parkinson's disease with dementia). Thirty-seven patients (59.7%) started to receive donepezil. Side-effects, including bradycardia, hypertension, aggressive behavior, increased tremor, were observed in 7 patients (18.9%). There was no correlation between the development of side-effects and polymorphisms of the CYP2D6 and MDR1 genes.

QT interval prolongation and Torsades de Pointes with donepezil, rivastigmine and galantamine

Background

Acetylcholinesterase inhibitors (AChEis) including donepezil, galantamine and rivastigmine are used to treat Alzheimer's disease (AD). This study aimed to evaluate evidence from the case report literature for an association between these agents and risk of QT interval prolongation and Torsades de Pointes (TdP) arrhythmia.

Methods

Published literature was mined with predetermined MeSH terms for each of donepezil, galantamine and rivastigmine, to identify cases of QT interval prolongation and TdP. Case reports were analysed using causality scales and a QT interval nomogram.

Results

A total of 13 case reports were found (10 for donepezil, 2 for galantamine and 1 for rivastigmine) with rate corrected QT interval (QT_c) prolongation. Five cases with donepezil exhibited TdP. TdP was not reported in the cases with galantamine and rivastigmine. The use of a QT heart rate nomogram highlighted risk with donepezil compared with the other two drugs and the application of the Naranjo causality scale suggested probable or possible causation for all donepezil cases. All patients had at least two other risk factors for TdP, including modifiable risk factors such as electrolyte disturbances, bradycardia, co-administration of QT prolonging drugs. A number of recent cases involved recent changes in medication.

Conclusion

Our evaluation of the case report literature suggests that there is evidence for a causal association between donepezil and QT_c/TdP risk. Attention to risk factors for QT_c prolongation/TdP should be exercised when prescribing donepezil and modifiable risk factors corrected. Owing to the low number of cases with galantamine and rivastigmine, further work is needed to establish whether these drugs may be more suitable than donepezil for patients with other risk factors for TdP.

Potency of Selected Berries, Grapes, and Citrus Fruit as Neuroprotective Agents

A healthy diet should nourish the brain with essential nutrients, including bioactive compounds, for normal brain functioning and to protect it from the negative effects of inflammation and oxidative stress. In this review, a concise summation of the protective effects of selected fruits, namely, berries, grapes, and citrus fruits, against neurological disorder is presented. The focus is on the neuroprotective potential of these fruits against neurodegenerative and mental disorders. The fruits selection was based on the vast reported pharmacological studies on their neuroprotection efficacies. Hence, the respective knowledge and limitations are discussed based on the biological and pharmacological evidence compiled from the previously reported laboratory, epidemiology, and intervention trials.

An update on the utility and safety of cholinesterase inhibitors for the treatment of Alzheimer's disease

Introduction: Alzheimer's disease (AD) is the most common cause of major neurocognitive disorders with a prevalence in the US of about 5.7 million in 2018. With the disease burden projected to increase dramatically in the coming years, it is imperative to review the current available treatment regimens for their safety and utility. The cholinesterase inhibitors (ChEIs) have continued to play a pivotal role in managing the symptoms and possibly slowing the rate of progression of AD since 1993. Owing to their being a mainstay in the treatment of AD, the safety and efficacy of prescribing these drugs needs to be reviewed often, especially with the approval of new formulations and doses.Areas covered: The three ChEIs currently approved by the FDA are donepezil, rivastigmine and galantamine. This article will review the safety and tolerability of these ChEIs and analyze the potential disease modifying properties of these drugs. The authors have reviewed all recent literature including review articles, meta-analyzes, clinical trials and more.Expert opinion: These ChEIs differ subtly in their mechanisms of action, in their tolerability and safety and FDA-approved indications. All are considered first-line, symptomatic treatments of the various phases of AD and may even have potentially disease-modifying effects.

Risk Factors for Cardiovascular Events in Patients on Antidementia Medications

OBJECTIVE

To identify characteristics associated with an increased risk of cardiovascular events in patients diagnosed with Alzheimer disease (AD) and treated with antidementia medications.

METHODS

Demographics, diagnoses, and medication usage of 30 433 Medicare patients were analyzed using 2006 to 2013 claims data and a combined model of screening, ranking and stepwise logistic regressions to evaluate factors associated with composite outcomes of 6 cardiovascular events.

RESULTS

Incidence rate of at least 1 cardiovascular event was 25.1%. Fifty-five factors were identified from the 10 381 candidate variables by the combined model with a c-statistic of 67% and an accuracy of 75%. Factors associated with increased risk of cardiovascular events include history of heart rhythm disorders, alteration of consciousness (odds ratio [OR]: 1.25; 95% confidence interval [CI]: 1.14-1.36), and usage of β-blockers (OR: 1.19; 95% CI: 1.13-1.27).

CONCLUSIONS

Clinicians should consider the increased risk of cardiovascular events in patients with AD with heart rhythm disorders and on β-blockers.

Correlation Between Donepezil and QTc Prolongation and Torsades de Pointes: A Very Rare Phenomenon

Dementia can be seen as a clinical syndrome featuring a decline in cognitive and psychological abilities that can cause disability. Two major kinds of drugs are available: N-methyl-D-aspartic acid receptor antagonists like memantine and acetylcholinesterase inhibitors such as galantamine, rivastigmine and donepezil. In this article, we have reviewed the available literature along with the provision of a snapshot of published cases in the literature We used the PubMed database for our search. The average age of patients was 80 years and above. Patients described in the literature belonged to both female and male gender, with female patients being predominant. Patients demonstrated associated atrioventricular (AV) block or ventricular premature contractions (VPC) or atrial fibrillation (AF) prior to developing torsades de pointes (TdP). Presenting complaints were either syncope or diarrhoea or accidental bradycardia. Mostly, the corrected QT interval (QTc) normalisation was associated with discontinuation of donepezil. We recommend further studies to determine this correlation between donepezil and incidence of QTc prolongation and TdP.

Heart Failure and Cognitive Impairment: Clinical Relevance and Therapeutic Considerations

Heart failure (HF) is a devastating condition characterized by poor quality of life, numerous complications, high rate of readmission and increased mortality. HF is the most common cause of hospitalization in the United States especially among people over the age of 64 years. The number of people grappling with the ill effects of HF is on the rise as the number of people living to an old age is also on the increase.

Several factors have been attributed to these high readmission and mortality rates among which are; poor adherence with therapy, inability to keep up with clinic appointments and even failure to recognize early symptoms of HF deterioration which may be a result of cognitive impairment.

Therefore, this review seeks to compile the most recent information about the links between HF and dementia or cognitive impairment. We also assessed the prognostic consequences of cognitive impairment complicating HF, therapeutic strategies among patients with HF and focus on future areas of research that would reduce the prevalence of cognitive impairment, reduce its severity and also ameliorate the effect of cognitive impairment coexisting with HF.

ABC Transporters in Extrahepatic Tissues: Pharmacological Regulation in Heart and Intestine

ATP binding cassette (ABC) transporters are transmembrane proteins expressed in secretory epithelia like the liver, kidneys and intestine, in the epithelia exhibiting barrier function such as the blood-brain barrier and placenta, and to a much lesser extent, in tissues like reproductive organs, lungs, heart and pancreas, among others. They regulate internal distribution of endogenous metabolites and xenobiotics including drugs of therapeutic use and also participate in their elimination from the body. We here describe the function and regulation of ABC transporters in the heart and small intestine, as examples of extrahepatic tissues, in which ABC proteins play clearly different roles. In the heart, they are involved in tissue pathogenesis as well as in protecting this organ against toxic compounds and druginduced oxidative stress. The small intestine is highly exposed to therapeutic drugs taken orally and, consequently, ABC transporters localized on its surface strongly influence drug absorption and pharmacokinetics. Examples of the ABC proteins currently described are Multidrug Resistance-associated Proteins 1 and 2 (MRP1 and 2) for heart and small intestine, respectively, and P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) for both organs.

Donepezil-induced QTc prolongation: A case report

Background

Several psychoactive medications are known to cause QTc prolongation. Patient factors also increase the risk for QTc prolongation, including bradycardia, female sex, older age, metabolic abnormalities, and polypharmacy. Donepezil, a cholinesterase inhibitor, prolongs the QTc interval through a multimodal mechanism.

Patient History

A 26-year-old African American female was admitted to the inpatient psychiatric hospital following a suicide attempt that was not an overdose. Past medical history was significant for major depression, traumatic brain injury, seizures, hemiplegia, gastroesophageal reflux disease, and tachycardia. Two baseline electrocardiograms (EKGs) were obtained showing normal QTc intervals. After several weeks, donepezil (5 mg by mouth once daily) was initiated for cognitive rehabilitation and titrated over 3 weeks to a dose of 20 mg. An EKG performed after the last dose change showed a prolonged QTc of 463 ms. Another follow-up EKG performed 9 days later showed further prolongation to 528 ms. Laboratory values were within normal limits during her hospital stay. Donepezil was discontinued completely, leading to normalization of the QTc interval.

Discussion

QTc prolongation and torsades de pointes have been identified in postmarketing case reports of donepezil. Instances of QTc prolongation have predominantly been documented in the geriatric population, primarily in those with additional risk factors. Additionally, current literature does not support the use of donepezil for neurocognitive rehabilitation in daily doses exceeding 10 mg. A temporal and causal relationship was observed between the initiation and titration of donepezil and development of QTc prolongation.

Dihydromyricetin ameliorates memory impairment induced by acute sleep deprivation

Dihydromyricetin (DHM), the major bioactive flavonoid ingredient extracted from the leaves of Ampelopsis grossedentata (Hand.-Mazz) W.T. Wang displays multiple pharmacological activities, including oxidation resistance, anti-tumour properties and free radical scavenging capacities. However, the role of DHM in sleep deprivation (SD)-induced memory impairments and its underlying molecular mechanisms are unclear. The aim of the present study was to evaluate the effects of DHM on oxidative stress and its role in ameliorating memory impairment induced by acute SD. DHM (100, 50, 25 mg/kg) and melatonin (10 mg/kg) were administered to mice via oral gavage. The open field test was used to evaluate motor function. Spatial learning and memory were assessed using the Morris water maze task. Malondialdehyde, glutathione, and glutathione disulfide levels, as well as superoxide dismutase enzyme activity, were assessed to determine the level of oxidative stress. In addition, we employed quantitative real-time PCR assays to examine the gene expression of 29 key proteins, including protein kinase A (PKA), cAMP response element binding protein (CREB), and adcy1. The levels of proteins including those of GABA_BR_S, GABA_ARα5, GluR1, BDNF and PSD95, were detected by western blotting. The results showed that DHM significantly attenuated SD-induced spatial learning and memory impairments (P < 0.01). The possible underlying mechanisms of DHM may be attributed to its ability to reduce oxidative stress and restore synaptic plasticity.

Electrocardiogram Changes of Donepezil Administration in Elderly Patients with Ischemic Heart Disease

Objective

Donepezil, a widely used cholinesterase inhibitor for treating Alzheimer's disease, has been reported to induce bradyarrhythmias and torsade de pointes. In this study, we aimed at determining electrocardiogram changes of donepezil administration in elderly patients with ischemic heart disease, who tend to suffer from cognitive disorders.

Methods

Sixty patients with ischemic heart disease and mild cognitive impairment were treated with donepezil (5 mg/day) and followed up for at least four weeks. A twenty-four-hour ambulatory electrocardiogram was performed for the analysis of heart rate variability. The ECG parameters including heart rate (HR), PR and RR intervals, QT interval, and QRS duration were recorded at the baseline and after donepezil administration.

Results

Donepezil administration resulted in significant reduction in mean HR and the lowest HR and prolongation of PR and RR intervals, whereas it had no significant effects on QRS duration and QT parameters including QT, corrected QT interval, QT dispersion, and T_peak-end interval. HRV analysis showed that donepezil administration significantly improved parasympathetic function, indicated by decreased low/high frequency (LF/HF) ratio and high frequency (HF) components and oscillation of RR intervals.

Conclusions

These data demonstrated that donepezil administration decreased HR, prolonged PR interval, and increased parasympathetic function without affecting QRS duration and QT intervals, suggesting that it can be used safely in elderly patients with ischemic heart disease.

Efficacy and Safety of Donepezil in Chinese Patients with Severe Alzheimer's Disease: A Randomized Controlled Trial

BACKGROUND

Donepezil has been used worldwide for the treatment of severe Alzheimer's disease (AD). Whether it is also appropriate for severe AD in Chinese patients remains unknown.

OBJECTIVE

To determine whether donepezil is effective and tolerable for Chinese patients with severe AD.

METHODS

The present study was a 24-week, multicenter, double-blind, randomized, placebo-controlled, parallel-group study conducted at 38 investigational hospitals in China. Patients with severe AD were enrolled in this trial. Patients were randomly assigned in a 1:1 ratio to receive either donepezil or placebo (5 mg for 6 weeks and10 mg for the remaining 18 weeks). The efficacy for donepezil were evaluated by the SIB, the Clinician's Interview-Based Impression of Change-Plus caregiver input (CIBIC-plus) and the MMSE. Safety parameters were monitored throughout.

RESULTS

A total of 313 patients included the donepezil (n = 157) and the placebo groups (n = 156). Donepezil group improved more in SIB scores (least squares [LS] mean difference: 4.8, 95% CI 1.56 to 8.08, p = 0.004) and CIBIC-plus scores (drug-placebo difference: -0.4, 95% CI -0.66 to 0.03, p = 0.04) than placebo groups at Week 24. The MMSE scores between drug and placebo groups did not differ significantly. Twenty-nine patients with serious adverse events (SAEs) were reported in donepezil (n = 11) and placebo groups (n = 18) (p = 0.08). Most SAEs were not considered drug-related.

CONCLUSION

Donepezil for 24 weeks was more effective than placebo and showed good safety and tolerability in Chinese patients with severe AD. This study supports utility of the drug in severe stages of AD in the Chinese population.

Inhibitory effects of cholinesterase inhibitor donepezil on the Kv1.5 potassium channel

Kv1.5 channels carry ultra-rapid delayed rectifier K⁺ currents in excitable cells, including neurons and cardiac myocytes. In the current study, the effects of cholinesterase inhibitor donepezil on cloned Kv1.5 channels expressed in HEK29 cells were explored using whole-cell recording technique. Exposure to donepezil resulted in a rapid and reversible block of Kv1.5 currents, with an IC₅₀ value of 72.5 μM. The mutant R476V significantly reduced the binding affinity of donepezil to Kv1.5 channels, showing the target site in the outer mouth region. Donepezil produced a significant delay in the duration of activation and deactivation, and mutant R476V potentiated these effects without altering activation curves. In response to slowed deactivation time course, a typical crossover of Kv1.5 tail currents was clearly evident after bath application of donepezil. In addition, both this chemical and mutant R476V accelerated current decay during channel inactivation in a voltage-dependent way, but barely changed the inactivation and recovery curves. The presence of donepezil exhibited the use-dependent block of Kv1.5 currents in response to a series of depolarizing pulses. Our data indicate that donepezil can directly block Kv1.5 channels in its open and closed states.

Synthesis of fluorinated donepezil by palladium-catalyzed decarboxylative allylation of α-fluoro-β-keto ester with tri-substituted heterocyclic alkene and the self-disproportionation of its enantiomers

Catalytic asymmetric synthesis of fluorinated donepezil, a promising new therapeutic agent for Alzheimer's disease, was achieved.

Local Drug-Drug Interaction of Donepezil with Cilostazol at Breast Cancer Resistance Protein (ABCG2) Increases Drug Accumulation in Heart

Clinical reports indicate that cardiotoxicity due to donepezil can occur after coadministration with cilostazol. We speculated that the concentration of donepezil in heart tissue might be increased as a result of interaction with cilostazol at efflux transporters such as P-glycoprotein (P-gp, ABCB1) and breast cancer resistance protein (BCRP, ABCG2), which are expressed in many tissues including the heart, and our study tested this hypothesis. First, donepezil was confirmed to be a substrate of both BCRP and P-glycoprotein in transporter-transfected cells in vitro. Cilostazol inhibited BCRP and P-glycoprotein with half-inhibitory concentrations of 130 nM and 12.7 μM, respectively. Considering the clinically achievable unbound plasma concentration of cilostazol (about 200 nM), it is plausible that BCRP-mediated transport of donepezil would be affected by cilostazol in vivo. Indeed, in an in vivo rat study, we found that coadministration of cilostazol significantly increased the concentrations of donepezil in the heart and brain, where BCRP functions as a part of the blood-tissue barrier, whereas the plasma concentration of donepezil was unaffected. In addition, in vitro accumulation of donepezil in heart tissue slices of rats was significantly increased in the presence of cilostazol. These results indicate that donepezil-cilostazol interaction at BCRP may be clinically relevant in heart and brain tissues. In other words, the tissue distribution of drugs can be influenced by drug-drug interaction (DDI) at efflux transporters in certain tissues (local DDI) without any apparent change in plasma concentration (systemic DDI).

A case of donepezil-related torsades de pointes

An 80-year-old woman with Alzheimer's dementia presented with diarrhoea, vomiting and worsening confusion following an increase in donepezil dose from 5 to 10 mg. The ECG revealed prolongation of QTc interval. Soon after admission, she became unresponsive with polymorphic ventricular tachycardia (VT). Cardiopulmonary resuscitation with a 200 J shock was successful in establishing cardiac output. Following the discontinuation of donepezil, the QTc interval normalised and no further arrhythmias were recorded. Treatment with anticholinesterase inhibitors may result in life-threatening VT. Vigilance is required for the identification of this condition in patients presenting with presyncope, syncope or seizures.

Heart failure and Alzheimer's disease

It has recently been proposed that heart failure is a risk factor for Alzheimer's disease. Decreased cerebral blood flow and neurohormonal activation due to heart failure may contribute to the dysfunction of the neurovascular unit and cause an energy crisis in neurons. This leads to the impaired clearance of amyloid beta and hyperphosphorylation of tau protein, resulting in the formation of amyloid beta plaques and neurofibrillary tangles. In this article, we will summarize the current understanding of the relationship between heart failure and Alzheimer's disease based on epidemiological studies, brain imaging research, pathological findings and the use of animal models. The importance of atherosclerosis, myocardial infarction, atrial fibrillation, blood pressure and valve disease as well as the effect of relevant medications will be discussed.

Effects of donepezil on hERG potassium channels

Donepezil is a potent, selective inhibitor of acetylcholinesterase, which is used for the treatment of Alzheimer's disease. Whole-cell patch-clamp technique and Western blot analyses were used to study the effects of donepezil on the human ether-a-go-go-related gene (hERG) channel. Donepezil inhibited the tail current of the hERG in a concentration-dependent manner with an IC50 of 1.3 μM. The metabolites of donepezil, 6-ODD and 5-ODD, inhibited the hERG currents in a similar concentration-dependent manner; the IC50 values were 1.0 and 1.5 μM, respectively. A fast drug perfusion system demonstrated that donepezil interacted with both the open and inactivated states of the hERG. A fast application of donepezil during the tail currents inhibited the open state of the hERG in a concentration-dependent manner with an IC50 of 2.7 μM. Kinetic analysis of donepezil in an open state of the hERG yielded blocking and unblocking rate constants of 0.54 µM(-1)s(-1) and 1.82 s(-1), respectively. The block of the hERG by donepezil was voltage-dependent with a steep increase across the voltage range of channel activation. Donepezil caused a reduction in the hERG channel protein trafficking to the plasma membrane at low concentration, but decreased the channel protein expression at higher concentrations. These results suggest that donepezil inhibited the hERG at a supratherapeutic concentration, and that it did so by preferentially binding to the activated (open and/or inactivated) states of the channels and by inhibiting the trafficking and expression of the hERG channel protein in the plasma membrane.

Encephalopathy from unintentional donepezil and memantine ingestion

Donepezil and memantine are commonly prescribed antidementia drugs. There is a paucity of literature concerning pediatric ingestions of these drugs. We describe a case of a 2-year-old child who developed encephalopathy after an unintentional ingestion of donepezil and memantine. A 2-year-old girl was found by her family members agitated and reporting visual hallucinations. In the emergency department, she became sedated and had rightward eye deviation. She was hospitalized and had extensive neurological and infectious disease testing that was unremarkable, except for an electroencephalogram, which showed a nonspecific encephalopathy. She recovered with supportive care for 72 hours. Serum concentrations of donepezil and memantine measured on arrival were 470 ng/mL (therapeutic range, 25-50 ng/mL) and 32 ng/mL (therapeutic range, 70-150 ng/mL), respectively. This case demonstrates that unintentional ingestions of memantine and donepezil can potentially cause significant and prolonged neurological symptoms in pediatric patients.

Cardiovascular pharmacodynamics of donepezil hydrochloride on the PR and QT intervals in patients with dementia

OBJECTIVE

Although several case reports suggested that donepezil hydrochloride can induce bradycardia or atrioventricular block, the details remain unclear. We implemented a study of the impact of donepezil hydrochloride administration on PR, RR, and QT intervals.

METHODS

The subjects were 18 patients who were diagnosed with either dementia or cognitive disorder (DSM-IV-TR) and were hospitalized between January 2011 and December 2012. After hospitalization, they were treated with donepezil hydrochloride. Clinical parameters and electrocardiograms before and after the administration of donepezil hydrochloride were retrieved from the patients' medical records.

RESULTS

After the administration of donepezil hydrochloride, the mean PR interval significantly increased from 177.3 ± 30.9 to 186.8 ± 38.4 ms (p<0.001). And the mean RR interval also significantly increased from 850.3 ± 112.5 to 886.7 ± 136.4 ms (p=0.014). The mean difference in the PR interval before and after the administration of donepezil hydrochloride was 9.5 ± 17.1 (range=-21.0-44.0) ms. The QT intervals were unaffected by the administration of donepezil hydrochloride.

CONCLUSIONS

Care should be taken when administering donepezil to patients with atrioventricular block, or patients taking other drugs that can prolong the PR interval. Copyright © 2014 John Wiley & Sons, Ltd.

Influences of donepezil on cardiovascular system--possible therapeutic benefits for heart failure--donepezil cardiac test registry (DOCTER) study

To study prospectively influences of donepezil, an acetylcholinesterase inhibitor against Alzheimer disease, on cardiovascular system, we evaluated cardiovascular changes occurring during new initialized treatment with donepezil in 49 dementia patients over 6 months. No patient suffered from cardiovascular events. In clinical changes between baseline and the first evaluation after donepezil treatment, heart rate and plasma brain natriuretic peptide (BNP) levels as a marker for heart failure did not change (BNP: 59.62 ± 62.71 pg/mL at baseline to 53.18 ± 42.34 pg/mL at first evaluation; P = 0.262). We further examined plasma BNP levels in 2 groups into which the patients were divided at baseline according to the cut-off plasma BNP level of 60 pg/mL. In patients with high level of BNP, the BNP levels decreased after administration of donepezil (116.39 ± 76.58 pg/mL at baseline to 82.24 ± 46.64 pg/mL at first evaluation; P = 0.011) with the tendency to be reduced in the follow-up period. BNP did not change in patients with low level of BNP. Donepezil seemed to be safe in patients with dementia without symptomatic heart disease and significantly decreased plasma BNP levels in patients with subclinical chronic heart failure.

Citalopram, QTc interval prolongation, and torsade de pointes. How should we apply the recent FDA ruling?

Recently, both the manufacturer of citalopram and the US Food and Drug Administration have warned health care providers and patients about new information implicating drug-induced QTc interval prolongation and torsade de pointes when using citalopram in doses >40 mg/day. This warning is not placed in the context of either benefits or risks in real-world clinical practice, leaving clinicians with an untenable choice between depriving patients of high-dose citalopram or malpractice litigation. We reviewed the literature and found no cases of citalopram-induced sudden cardiac death among patients taking up to 60 mg/day of citalopram and free of risk factors for QTc interval prolongation and torsade de pointes. Because psychotropic drug-induced sudden cardiac death is an outlier in the absence of identified risk factors for QTc interval prolongation and torsade de pointes, we do not believe current Phase 3 and Phase 4 studies provide sufficient information to limit current prescribing practices for citalopram (20 mg to 60 mg/day). We urge drug manufacturers and regulatory agencies to periodically publish full case reports of psychotropic drug-induced QTc interval prolongation, torsade de pointes, and sudden cardiac death so that clinicians and investigators may better understand the clinical implications of prescribing such drugs as citalopram.

[Shortening of donepezil-induced QTc prolongation with a change in the interacting drug, after electrocardiograph monitoring by community pharmacists: a case report]

We used a mobile electrocardiograph to manage the adverse effects and interactions of drugs, especially QT-prolonging drugs, in a community pharmacy setting. We report the case of a patient in whom the risk of drug-induced torsades de pointes (TdP) was lowered, after monitoring by community pharmacists.

CASE

An 80-year-old woman was under donepezil (5 mg/d) therapy for Alzheimer's disease and also taking other drugs that interact with donepezil, namely, benidipine (8 mg/d) and atorvastatin (10 mg/d). The patient was visited almost every month, and an electrocardiogram was usually obtained. QTc prolongation (avg. 470±9 ms) was observed in the first to third tests. Her doctor was informed about these results and the risk factors (advanced age, gender, and drugs interactions (benidipine and atorvastatin)) associated with TdP and asked to respond promptly since several cases of donepezil-induced TdP have been reported. As a result, benidipine was replaced with amlodipine, while the remaining drugs were continued. After the change, a significant decrease in QTc values were observed in the fourth to seventh tests (avg. 441±9 ms, p=0.010), thereby indicating a decrease in TdP risk. The Drug Interaction Probability Scale (object drug, donepezil; precipitant drug, benidipine) score was +6 (probable). Thus, QTc shortening was a result of differences in donepezil-benidipine and donepezil-amlodipine interactions.

Which cholinesterase inhibitor is the safest for the heart in elderly patients with Alzheimer's disease?

OBJECTIVE

Cholinesterase inhibitors (ChEIs) are widely used for the treatment of Alzheimer's disease (AD); however, their cholinergic side effects on the cardiovascular system are still unclear. In this study, we aimed to examine the side effects caused by donepezil, rivastigmine, and galantamine on cardiac rhythm and postural blood pressure changes in elderly patients with AD.

METHODS

Of 204 consecutive elderly patients who were newly diagnosed with AD, 162 were enrolled and underwent comprehensive geriatric assessments. The electrocardiographs (ECGs) and blood pressures were recorded at the baseline and 4 weeks after the dose of 10 mg/d of donepezil, 10 cm(2)/d of rivastigmine, and 24 mg/d of galantamine.

RESULTS

There were no changes relative to the baseline in any of the ECG parameters or arterial blood pressure with any of the administered ChEIs.

CONCLUSION

It was demonstrated that none of the 3 ChEIs were associated with increased negative chronotropic, arrhythmogenic, and hypotensive effects for the elderly patients with AD.

Cardiac safety of donepezil in elderly patients with Alzheimer disease

OBJECTIVE

Donepezil is a widely used cholinesterase inhibitor for the treatment of Alzheimer's disease (AD), however its cholinergic adverse side effects on the cardiovascular system are still unclear. In this study, we aimed to examine the adverse side effects caused by donepezil on cardiac rhythm and postural blood pressure changes in elderly patients with Alzheimer Disease.

METHODS

The ECG parameters including heart rate, PR, QT, QTc interval and QRS duration and postural blood pressure changes were recorded at the baseline and at each donepezil dose level (5 and 10 mg/d). Patients Seventy-one consecutive patients who were referred by primary care centers to a Geriatric Clinic were enrolled and underwent comprehensive geriatric assessment.

RESULTS

Fifty-two subjects completed the study. There were no significant changes relative to the baseline in any of the ECG parameters or arterial blood pressure at any of the investigated dosages of donepezil.

CONCLUSION

It was demonstrated that donepezil was not associated with increased negative chronotropic, arrhythmogenic or hypotensive effects for elderly patients with Alzheimer's disease.