Use of clarithromycin and adverse cardiovascular events among older patients receiving donepezil: a population-based, nested case-control study

Safety and Tolerability of Antimicrobial Agents in the Older Patient

Older patients are at high risk of infections, which often present atypically and are associated with high morbidity and mortality. Antimicrobial treatment in older individuals with infectious diseases represents a clinical challenge, causing an increasing burden on worldwide healthcare systems; immunosenescence and the coexistence of multiple comorbidities determine complex polypharmacy regimens with an increase in drug-drug interactions and spread of multidrug-resistance infections. Aging-induced pharmacokinetic and pharmacodynamic changes can additionally increase the risk of inappropriate drug dosing, with underexposure that is associated with antimicrobial resistance and overexposure that may lead to adverse effects and poor adherence because of low tolerability. These issues need to be considered when starting antimicrobial prescriptions. National and international efforts have been made towards the implementation of antimicrobial stewardship (AMS) interventions to help clinicians improve the appropriateness and safety of antimicrobial prescriptions in both acute and long-term care settings. AMS programs were shown to decrease consumption of antimicrobials and to improve safety in hospitalized patients and older nursing home residents. With the abundance of antimicrobial prescriptions and the recent emergence of multidrug resistant pathogens, an in-depth review of antimicrobial prescriptions in geriatric clinical practice is needed. This review will discuss the special considerations for older individuals needing antimicrobials, including risk factors that shape risk profiles in geriatric populations as well as an evidence-based description of antimicrobial-induced adverse events in this patient population. It will highlight agents of concern for this age group and discuss interventions to mitigate the effects of inappropriate antimicrobial prescribing.

Comparative risk of cardiac arrhythmias associated with acetylcholinesterase inhibitors used in treatment of dementias - A narrative review

Donepezil, galantamine, and rivastigmine are the three acetylcholinesterase inhibitors (AChEIs), out of a total of only four medications prescribed in the treatment of Alzheimer's Disease (AD) and related dementias. These medications are known to be associated with bradycardia given their mechanism of action of increasing acetylcholine (ACh). However, in March 2015, donepezil was added to the CredibleMeds "known-risk" category, a list where medications have a documented risk for acquired long-QT syndrome (ALQTS) and torsades de pointes (TdP) - a malignant ventricular arrhythmia that is a different adverse event than bradycardia (and is not necessarily associated with ACh action). The purpose of this article is to review the three AChEIs, especially with regards to mechanistic differences that may explain why only donepezil poses this risk; several pharmacological mechanisms may explain why. However, from an empirical point-of-view, aside from some case-reports, only a limited number of studies have generated relevant information regarding AChEIs' and electrocardiogram findings; none have specifically compared donepezil against galantamine or rivastigmine for malignant arrhythmias such as TdP. Currently, the choice of one of the three AChEIs for treatment of AD symptoms is primarily dependent upon clinician and patient preference. However, clinicians should be aware of the potential increased risk associated with donepezil. There is a need to examine the comparative risk of malignant arrhythmias among AChEIs users in real-world practice; this may have important implications with regards to changes in AChEI prescribing patterns.

Clarithromycin use and the risk of mortality and cardiovascular events: A systematic review and meta-analysis

Background

Although studies reported increased cardiovascular (CV) risks in patients treated with macrolides, the risks remain controversial among clarithromycin (CLR) users. We aimed to summarize the association between CLR use and the risks of mortality and CV events.

Methods

We searched PubMed, EMBASE, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) and observational studies with population exposed to CLR published until December 31^st, 2018. These studies reported either all-cause mortality (primary outcome) or CV adverse events (secondary outcomes) based on multivariate models. Effect measures were synthesized by study design and follow-up duration (long-term, ≥ 1 year; short-term, ≤ 3 months; and immediate, ≤ 2 weeks). This study has been registered on PROSPERO (ID: CRD42018089605).

Results

This meta-analysis included 13 studies (3 RCTs and 10 observational studies) and 8,351,815 subjects (1,124,672 cases and 7,227,143 controls). Overall, CLR use was not associated with increased long-term all-cause mortality (pooled rate ratio RR = 1.09, 95% CI = 0.91–1.32), either among patients with or without comorbidities of cardiovascular diseases. Comparing CLR users to placebo, there is no additional risks of cardiac mortality (pooled RR = 1.03, 95% CI = 0.53–2.01), acute myocardial infarction (pooled RR = 1.29, 95% CI = 0.98–1.68), and arrhythmia (pooled RR = 0.90, 95% CI = 0.62–1.32).

Conclusions

Our findings suggested no significant association between CLR use and subsequent long-term all-cause mortality, regardless having comorbidity of cardiovascular diseases or not. Further RCTs investigating the short-term CV risks of CLR use compared to alternative antibiotics are warranted, particularly in high-risk populations.

Duration and life-stage of antibiotic use and risk of cardiovascular events in women

AIMS

Growing data suggest that antibiotic exposure is associated with a long-lasting alteration in gut microbiota, and may be related to subsequent cardiovascular disease (CVD). We investigated associations of life-stage and duration of antibiotic exposure during adulthood with subsequent CVD events.

METHODS AND RESULTS

This study included 36 429 women initially free of CVD and cancer from the Nurses' Health Study. We estimated hazard ratios (HRs) for CVD (a composite endpoint of coronary heart disease or stroke) according to duration of antibiotic use in young (age 20-39), middle (age 40-59), and late (age 60 and older) adulthood. During an average of 7.6 years of follow-up, 1056 participants developed CVD. Women with long-term use of antibiotics (for ≥2 months) in late adulthood had a significantly increased risk of CVD (HR 1.32, 95% confidence interval 1.03-1.70) after adjustment for covariates (such as demographic factors, diet and lifestyle, reasons for antibiotic use, overweight or obesity, disease status, and other medication use), as compared to women who did not use antibiotics in this life-stage. Longer duration of antibiotic use in middle adulthood was also related to higher risk of CVD (P trend = 0.003) after controlling for these covariates. There was no significant relationship between the use in young adulthood and the risk of CVD.

CONCLUSION

In this study which examined the antibiotic use in different life-stages, longer duration of exposure to antibiotics in the middle and older adulthood was related to an increased risk of future CVD events among elderly women at usual risk.

Inappropriate pharmacological treatment in older adults affected by cardiovascular disease and other chronic comorbidities: a systematic literature review to identify potentially inappropriate prescription indicators

Avoiding medications in which the risks outweigh the benefits in the elderly patient is a challenge for physicians, and different criteria to identify inappropriate prescription (IP) exist to aid prescribers. Definition of IP indicators in the Italian geriatric population affected by cardiovascular disease and chronic comorbidities could be extremely useful for prescribers and could offer advantages from a public health perspective. The purpose of the present study was to identify IP indicators by means of a systematic literature review coupled with consensus criteria. A systematic search of PubMed, EMBASE, and CENTRAL databases was conducted, with the search structured around four themes and combining each with the Boolean operator “and”. The first regarded “prescriptions”, the second “adverse events”, the third “cardiovascular conditions”, and the last was planned to identify studies on “older people”. Two investigators independently reviewed titles, abstracts, full texts, and selected articles addressing IP in the elderly affected by cardiovascular condition using the following inclusion criteria: studies on people aged ≥65 years; studies on patients with no restriction on age but with data on subjects aged ≥65 years; and observational effectiveness studies. The database searches produced 5,742 citations. After removing duplicates, titles and abstracts of 3,880 records were reviewed, and 374 full texts were retrieved that met inclusion criteria. Thus, 49 studies reporting 32 potential IP indicators were included in the study. IP indicators regarded mainly drug–drug interactions, cardio- and cerebrovascular risk, bleeding risk, and gastrointestinal risk; among them, only 19 included at least one study that showed significant results, triggering a potential warning for a specific drug or class of drugs in a specific context. This systematic review demonstrates that both cardiovascular and non-cardiovascular drugs increase the risk of adverse drug reactions in older adults with cardiovascular diseases.

A population-based analysis of the risk of drug interaction between clarithromycin and statins for hospitalisation or death

Background

Clarithromycin, known as a potent inhibitor of the cytochrome P450 isoenzyme CYP3A, may increase the plasma concentration of statins metabolized by this pathway; therefore, increase the risk of interaction with statins in reference to pharmacokinetic studies. This study aimed to characterize whether the concomitant use of a statin with clarithromycin is associated with serious outcomes among adult persons.

Methods

Health claims data of adult persons in the Regional Sickness Fund of Burgenland, Austria, who filled a prescription for clarithromycin between July 1, 2009 and June 30, 2012 were reviewed retrospectively. We assumed that the risk of hospitalisation increases acutely with the indication for taking an antibiotic, whereas statin use can be considered a chronic exposure with a low constant effect on hospitalisation. When defining the population as persons taking clarithromycin and the use of statins as the exposure we could achieve a comparable effect in both groups from the acute condition on hospitalisation. Therefore, we defined exposed patients as those who had overlapping treatment with a statin and unexposed controls as those who had filled a prescription for clarithromycin without concomitant statin therapy. Outcome was defined as a composite of hospital admission or death within 30 days after starting clarithromycin. We used generalised linear regression to model an association between outcome and exposure to statins.

Results

Among 28,484 prescriptions of clarithromycin, 2317 persons were co-exposed to statins. Co-administration of CYP3A4 metabolized statins and clarithromycin was associated with a 2.11 fold increased risk of death or hospitalisation (95 % confidence interval [CI]: 1.79–2.48). This effect was explained by age, evidence of cardiovascular disease, diabetes mellitus and utilization of other antibiotics (multivariable adjusted risk ratio: 1.02, 95 % CI: 0.85–1.22). The sensitivity analyses did not change the significance of effect.

Conclusions

The risk for hospitalisation or death in persons receiving clarithromycin increases with age and cardiovascular disease but is not causally associated with statin-clarithromycine co-administration.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0134-y) contains supplementary material, which is available to authorized users.

The impact of drug interactions and polypharmacy on antimicrobial therapy in the elderly

Infectious diseases are more prevalent in older people than in younger adults, and represent a major healthcare issue in older populations. Indeed, infections in the elderly are often associated with higher morbidity and mortality, and may present atypically. Additionally, older patients are generally treated with polypharmacy regimens, which increase the likelihood of drug-drug interactions when the prescription of an antimicrobial agent is needed. A progressive impairment in the functional reserve of multiple organs may affect either pharmacokinetics or pharmacodynamics during aging. Changes in body composition occurring with advancing age, reduced liver mass and perfusion, and reduced renal excretion may affect either pharmacokinetics or pharmacodynamics. These issues need to be taken into account when prescribing antimicrobial agents to older complex patients taking multiple drugs. Interventions aimed at improving the appropriateness and safety of antimicrobial prescriptions have been proposed. Educational interventions targeting physicians may improve antimicrobial prescriptions. Antimicrobial stewardship programmes have been found to reduce the length of hospital stay and improve safety in hospitalized patients, and their use in long-term care facilities is worth testing. Computerized prescription and decision support systems, as well as interventions aimed at improving antimicrobial agents dosage in relation to kidney function, may also help to reduce the burden of interactions and inherent costs.

Pharmacokinetic and pharmacodynamic evaluation of donepezil for the treatment of Alzheimer's disease

INTRODUCTION

Donepezil is a highly selective acetylcholinesterase inhibitor and one of the only four drugs currently approved for treatment of Alzheimer's dementia. Providing high bioavailability and a very long half-time, donepezil is regarded as effective and well tolerable in Alzheimer's disease patients, even in difficult clinical conditions such as hepatic or renal impairment. It moderately improves cognitive and global functioning scores in patients with mild to moderate Alzheimer's disease over the course of 6 - 12 months, with open-label extension studies suggesting effects of even longer duration.

AREAS COVERED

We summarized relevant pharmacokinetic, pharmacodynamic, clinical trial and neuroimaging data of donepezil. A literature search was performed in the PubMed database; articles published until October 2013 have been considered for this review. Moreover, references from original work and reviews have been searched for further relevant literature.

EXPERT OPINION

Donepezil is one of the most frequently prescribed anti-dementia drugs. The recent additional approval of the 23 mg formulation will expand its use in patients with moderate to severe Alzheimer's disease. After numerous Phase III study failures of novel disease-modifying drugs for Alzheimer's disease, donepezil is likely going to stay a first-line therapeutic option in Alzheimer's disease in the upcoming years.

Comparing two types of macrolide antibiotics for the purpose of assessing population-based drug interactions

OBJECTIVE

Clarithromycin strongly inhibits enzyme cytochrome P450 3A4, preventing the metabolism of some other drugs, while azithromycin is a weak inhibitor. Accordingly, blood concentrations of other drugs increase with clarithromycin coprescription leading to adverse events. These macrolide antibiotics also differ on other properties that may impact outcomes. In this study, we compared outcomes in two groups of macrolide antibiotic users in the absence of potentially interacting drugs.

DESIGN

Population-based retrospective cohort study.

SETTING

Ontario, Canada, from 2003 to 2010.

PATIENTS

Patients (mean 74 years) prescribed clarithromycin (n=52 251) or azithromycin (referent group, n=46 618).

MAIN OUTCOMES

The primary outcomes were hospital admission within 30 days of a new antibiotic prescription with any of the 12 conditions examined separately (acute kidney injury, acute myocardial infarction, neuroimaging (proxy for delirium), hypotension, syncope, hyperkalaemia, hyponatraemia, hyperglycaemia, arrhythmia, ischaemic stroke, gastrointestinal bleeding and sepsis). The secondary outcome was mortality.

RESULTS

The baseline characteristics of the two groups, including patient demographics, comorbid conditions, infection type and prescribing physician specialty, were nearly identical. The median daily dose was 1000 mg for clarithromycin and 300 mg for azithromycin and the median duration of dispensing antibiotics was 10 and 5 days, respectively. There was no difference between the groups in the risk of hospitalisation for any condition studied (relative risk ranged from 0.67 to 1.23). Compared with azithromycin, clarithromycin was associated with a slightly higher risk of all-cause mortality (0.46% vs 0.37%, relative risk 1.25, 95% CI 1.03 to 1.52).

CONCLUSIONS

Clarithromycin can be used to assess drug interactions in population-based studies with azithromycin serving as a control group. However, any differences in mortality observed between the two antibiotic groups in the setting of other drug use may be partially attributable to factors beyond the inhibition of drug metabolising enzymes and transporters, as the difference for this outcome was significant.