Association Between Fluoroquinolones and Major Adverse Cardiovascular Events: A Systematic Review

Fluoroquinolones (FQs) are routinely administered antibiotics that have demonstrated an increased propensity to cause major adverse cardiovascular events (MACE). We conducted a systematic review aimed to investigate the association between FQ usage and the risk of MACE. A comprehensive literature search was conducted using PubMed, Scopus, and the Cochrane Library from inception to September 2023 to retrieve studies comparing FQ administration with placebo and reporting the occurrence of MACE. Relevant studies that explored the occurrence of MACE, defined as "acute myocardial infarction, stroke, cardiovascular mortality, arrhythmia, or heart failure" with FQ usage were eligible for inclusion. Four studies with a total of 42,808 patients were included. Levofloxacin, moxifloxacin, and gatifloxacin were observed to have an increased propensity to cause MACE, particularly arrhythmias, whereas ciprofloxacin was associated with the lowest risk of causing MACE. Despite the methodological diversity in the included studies, this systematic review uncovered a consistent trend of heightened likelihood of MACE with FQ administration across studies, suggesting that elevated serum concentrations of some FQs may correlate with higher risks of MACE development. This systematic review emphasizes the need for cautious administration of FQs, particularly in patients with a preexisting cardiovascular condition. Routine cardiac monitoring using electrocardiograms is warranted for patients on high doses of FQs to preemptively detect the development of MACE, particularly arrhythmias.

Fluoroquinolones do not provide added risk of out-of-hospital cardiac arrest: a nationwide study

AIM

Conflicting results have been reported regarding the association between fluoroquinolones (FQs) and the risk of out-of-hospital cardiac arrest (OHCA). In particular, it has not become clear whether OHCA in FQ users is related to the inherent comorbidities or whether there is a direct pro-arrhythmic effect of FQs. Therefore, we studied the relation between FQs and OHCA in the general population.

METHODS

Through Danish nationwide registries, we conducted a nested case-control study with OHCA cases of presumed cardiac causes and age/sex/OHCA date-matched non-OHCA controls from the general population. Conditional logistic regression models with adjustments for well-known risk factors of OHCA were employed to estimate the OR with 95% CI of OHCA comparing FQs with amoxicillin.

RESULTS

The study population consisted of 46 578 OHCA cases (mean: 71 years (SD: 14.40), 68.8% men) and 232 890 matched controls. FQ was used by 276 cases and 328 controls and conferred no increase in the odds of OHCA compared with amoxicillin use after controlling for the relevant confounders (OR: 0.91 (95% CI: 0.71 to 1.16)). The OR of OHCA associated with FQ use did not vary significantly by age (OR≤65: 0.96 (95% CI: 0.53 to 1.74), OR>65: 0.88 (95% CI: 0.67 to 1.16), p value interaction=0.7818), sex (ORmen: 0.96 (95% CI: 0.70 to 1.31), ORwomen: 0.80 (95% CI: 0.53 to 1.20), p value interaction=0.9698) and pre-existing cardiovascular disease (ORabsent: 1.02 (95% CI: 0.57 to 1.82), ORpresent: 0.98 (95% CI: 0.75 to 1.28), p value interaction=0.3884), including heart failure (ORabsent: 0.93 (95% CI: 0.72 to 1.22), ORpresent: 1.11 (95% CI: 0.61 to 2.02), p value interaction=0.7083) and ischaemic heart disease (ORabsent: 0.85 (95% CI: 0.64 to 1.12), ORpresent: 1.38 (95% CI: 0.86 to 2.21), p value interaction=0.6230).

CONCLUSION

Our findings do not support an association between FQ exposure and OHCA in the general population. This lack of association was consistent in men and women, in all age categories, and in the presence or absence of cardiovascular disease.

Analysis of clinical characteristics and automatic monitoring of drug-induced arrhythmias in 167,546 inpatients

OBJECTIVE

The purpose of this study was to analyze the occurrence characteristics, clinical manifestations, medication distribution, and incidence of drug-induced arrhythmias in a real-world inpatient population.

METHODS

According to the inclusion and exclusion criteria as well as the ADR evaluation criteria, we retrospectively evaluated hospitalized patients in 2019 using the arrhythmia module of the Adverse Drug Event Active Surveillance and Assessment System-II (ADE-ASAS-II). A detailed analysis was performed on the demographic data, ADR manifestations, and medication distribution of 2097 patients with drug-induced arrhythmias and QT interval prolongation.

RESULTS

Of the 167,546 hospitalized patients, there were 1809 cases of drug-induced arrhythmias, with an incidence of 1.08%. The ADRs in 45.35% of positive patients occurred within 3 days after medication administration, and 46.73% of the patients were 65 years old or older. The predominant ADRs identified in this study were extrasystole, tachycardia, and QT interval prolongation, of which the incidence was 0.20%. Levofloxacin was the most involved drug, and levofloxacin-associated rates of incidence of arrhythmia and QT interval prolongation were 1.24% and 0.44%, respectively. The risk factors for drug-induced arrhythmias were male sex, advanced age, emaciation, obesity, and underlying illnesses such as cardiovascular diseases, diabetes mellitus, cerebrovascular diseases, and hepatic and renal inadequacy (P < 0.05).

CONCLUSION

The incidence of drug-induced arrhythmias was in the range of common, while QTc interval prolongation was occasional. It is necessary to pay attention to patients with risk factors.

A Rare Case of Ciprofloxacin-Induced Bradycardia Recognized by a Smartwatch

Fluoroquinolones are known to cause cardiac side effects. The most common are ventricular arrhythmias and QT prolongation. We present a case of symptomatic bradycardia secondary to ciprofloxacin use in a patient who presented to the hospital after a smartwatch alert for bradycardia. We believe that the integration of wearable technology in the practice of medicine could provide valuable data and improve patient care in different settings.

High-dose gatifloxacin-based shorter treatment regimens for MDR/RR-TB

SETTING

The shorter treatment regimen (STR) for multidrug- or rifampicin-resistant tuberculosis (MDR/RR-TB) has achieved successful outcomes in many countries. However, there are few studies on high-dose gatifloxacin-based STR with adverse drug reactions (ADRs) and management.

DESIGN

A prospective observational study was conducted with MDR/RR-TB patients who were treated with a standardized 9 or 12 - month regimen: including gatifloxacin (Gfx), clofazimine (Cfz), ethambutol (EMB), and pyrazinamide (PZA), and supplemented by amikacin (Am), isoniazid (INH), and prothionamide (Pto) during an intensive phase of 4 or 6 - month. Monitored ADRs monthly until treatment completion and then followed up every three months for one year.

RESULTS

Among the 42 eligible patients, 35 (83.3%) completed treatment successfully, 1 (2.4%) lost to follow-up (LTFU), and 6 (14.3%) failed due to ADRs, with no death. The most important ADR was drug-induced liver damage, which occurred in 24 out of 42 (57.1%) patients and resulted in 4 (9.5%) failed treatments and 4 (9.5%) adjusted treatments. QT interval prolongation occurred in 17 out of 42 (40.5%) patients, 9 (21.4%) of them with the corrected QT interval according to Fridericia (QTcF) > 500 ms resulting in 7 (16.7%) adjusted treatments.

CONCLUSIONS

This study confirmed the effectiveness of the high-dose gatifloxacin-based STR but severe ADRs, especially hepatotoxicity and QT interval prolongation should never be ignored.

Antimicrobial stewardship programs in adult intensive care units in Latin America: Implementation, assessments, and impact on outcomes

OBJECTIVE

To assess the impact of antimicrobial stewardship programs (ASPs) in adult medical-surgical intensive care units (MS-ICUs) in Latin America.

DESIGN

Quasi-experimental prospective with continuous time series.

SETTING

The study included 77 MS-ICUs in 9 Latin American countries.

PATIENTS

Adult patients admitted to an MS-ICU for at least 24 hours were included in the study.

METHODS

This multicenter study was conducted over 12 months. To evaluate the ASPs, representatives from all MS-ICUs performed a self-assessment survey (0-100 scale) at the beginning and end of the study. The impact of each ASP was evaluated monthly using the following measures: antimicrobial consumption, appropriateness of antimicrobial treatments, crude mortality, and multidrug-resistant microorganisms in healthcare-associated infections (MDRO-HAIs). Using final stewardship program quality self-assessment scores, MS-ICUs were stratified and compared among 3 groups: ≤25th percentile, >25th to <75th percentile, and ≥75th percentile.

RESULTS

In total, 77 MS-ICU from 9 Latin American countries completed the study. Twenty MS-ICUs reached at least the 75th percentile at the end of the study in comparison with the same number who remain within the 25th percentile (score, 76.1 ± 7.5 vs 28.0 ± 7.3; P < .0001). Several indicators performed better in the MS-ICUs in the 75th versus 25th percentiles: antimicrobial consumption (143.4 vs 159.4 DDD per 100 patient days; P < .0001), adherence to clinical guidelines (92.5% vs 59.3%; P < .0001), validation of prescription by pharmacist (72.0% vs 58.0%; P < .0001), crude mortality (15.9% vs 17.7%; P < .0001), and MDRO-HAIs (9.45 vs 10.96 cases per 1,000 patient days; P = .004).

CONCLUSION

MS-ICUs with more comprehensive ASPs showed significant improvement in antimicrobial utilization.

Antibiotics for secondary prevention of coronary heart disease

BACKGROUND

Coronary heart disease is the leading cause of mortality worldwide with approximately 7.4 million deaths each year. People with established coronary heart disease have a high risk of subsequent cardiovascular events including myocardial infarction, stroke, and cardiovascular death. Antibiotics might prevent such outcomes due to their antibacterial, antiinflammatory, and antioxidative effects. However, a randomised clinical trial and several observational studies have suggested that antibiotics may increase the risk of cardiovascular events and mortality. Furthermore, several non-Cochrane Reviews, that are now outdated, have assessed the effects of antibiotics for coronary heart disease and have shown conflicting results. No previous systematic review using Cochrane methodology has assessed the effects of antibiotics for coronary heart disease.

OBJECTIVES

We assessed the benefits and harms of antibiotics compared with placebo or no intervention for the secondary prevention of coronary heart disease.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-EXPANDED, and BIOSIS in December 2019 in order to identify relevant trials. Additionally, we searched TRIP, Google Scholar, and nine trial registries in December 2019. We also contacted 11 pharmaceutical companies and searched the reference lists of included trials, previous systematic reviews, and other types of reviews.

SELECTION CRITERIA

Randomised clinical trials assessing the effects of antibiotics versus placebo or no intervention for secondary prevention of coronary heart disease in adult participants (≥18 years). Trials were included irrespective of setting, blinding, publication status, publication year, language, and reporting of our outcomes.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data. Our primary outcomes were all-cause mortality, serious adverse event according to the International Conference on Harmonization - Good Clinical Practice (ICH-GCP), and quality of life. Our secondary outcomes were cardiovascular mortality, myocardial infarction, stroke, and sudden cardiac death. Our primary time point of interest was at maximum follow-up. Additionally, we extracted outcome data at 24±6 months follow-up. We assessed the risks of systematic errors using Cochrane 'Rosk of bias' tool. We calculated risk ratios (RRs) with 95% confidence intervals (CIs) for dichotomous outcomes. We calculated absolute risk reduction (ARR) or increase (ARI) and number needed to treat for an additional beneficial outcome (NNTB) or for an additional harmful outcome (NNTH) if the outcome result showed a beneficial or harmful effect, respectively. The certainty of the body of evidence was assessed by GRADE.

MAIN RESULTS

We included 38 trials randomising a total of 26,638 participants (mean age 61.6 years), with 23/38 trials reporting data on 26,078 participants that could be meta-analysed. Three trials were at low risk of bias and the 35 remaining trials were at high risk of bias. Trials assessing the effects of macrolides (28 trials; 22,059 participants) and quinolones (two trials; 4162 participants) contributed with the vast majority of the data. Meta-analyses at maximum follow-up showed that antibiotics versus placebo or no intervention seemed to increase the risk of all-cause mortality (RR 1.06; 95% CI 0.99 to 1.13; P = 0.07; I² = 0%; ARI 0.48%; NNTH 208; 25,774 participants; 20 trials; high certainty of evidence), stroke (RR 1.14; 95% CI 1.00 to 1.29; P = 0.04; I² = 0%; ARI 0.73%; NNTH 138; 14,774 participants; 9 trials; high certainty of evidence), and probably also cardiovascular mortality (RR 1.11; 95% CI 0.98 to 1.25; P = 0.11; I²= 0%; 4674 participants; 2 trials; moderate certainty of evidence). Little to no difference was observed when assessing the risk of myocardial infarction (RR 0.95; 95% CI 0.88 to 1.03; P = 0.23; I² = 0%; 25,523 participants; 17 trials; high certainty of evidence). No evidence of a difference was observed when assessing sudden cardiac death (RR 1.08; 95% CI 0.90 to 1.31; P = 0.41; I² = 0%; 4520 participants; 2 trials; moderate certainty of evidence). Meta-analyses at 24±6 months follow-up showed that antibiotics versus placebo or no intervention increased the risk of all-cause mortality (RR 1.25; 95% CI 1.06 to 1.48; P = 0.007; I² = 0%; ARI 1.26%; NNTH 79 (95% CI 335 to 42); 9517 participants; 6 trials; high certainty of evidence), cardiovascular mortality (RR 1.50; 95% CI 1.17 to 1.91; P = 0.001; I² = 0%; ARI 1.12%; NNTH 89 (95% CI 261 to 49); 9044 participants; 5 trials; high certainty of evidence), and probably also sudden cardiac death (RR 1.77; 95% CI 1.28 to 2.44; P = 0.0005; I² = 0%; ARI 1.9%; NNTH 53 (95% CI 145 to 28); 4520 participants; 2 trials; moderate certainty of evidence). No evidence of a difference was observed when assessing the risk of myocardial infarction (RR 0.95; 95% CI 0.82 to 1.11; P = 0.53; I² = 43%; 9457 participants; 5 trials; moderate certainty of evidence) and stroke (RR 1.17; 95% CI 0.90 to 1.52; P = 0.24; I² = 0%; 9457 participants; 5 trials; high certainty of evidence). Meta-analyses of trials at low risk of bias differed from the overall analyses when assessing cardiovascular mortality at maximum follow-up. For all other outcomes, meta-analyses of trials at low risk of bias did not differ from the overall analyses. None of the trials specifically assessed serious adverse event according to ICH-GCP. No data were found on quality of life.

AUTHORS' CONCLUSIONS

Our present review indicates that antibiotics (macrolides or quinolones) for secondary prevention of coronary heart disease seem harmful when assessing the risk of all-cause mortality, cardiovascular mortality, and stroke at maximum follow-up and all-cause mortality, cardiovascular mortality, and sudden cardiac death at 24±6 months follow-up. Current evidence does, therefore, not support the clinical use of macrolides and quinolones for the secondary prevention of coronary heart disease. Future trials on the safety of macrolides or quinolones for the secondary prevention in patients with coronary heart disease do not seem ethical. In general, randomised clinical trials assessing the effects of antibiotics, especially macrolides and quinolones, need longer follow-up so that late-occurring adverse events can also be assessed.

A case of torsades de pointes induced by the third-generation EGFR-TKI, osimertinib combined with moxifloxacin

Background

Torsade de pointes (TdP) is a malignant arrhythmia that can be induced by QT internal prolongation due to a variety of factors. Here we report an elderly patient with advanced non-small cell lung cancer (NSCLC) had sudden TdP during hospitalization, which was caused by multiple factors such as osimertinib, moxifloxacin and patient self-factors.

Case presentation

An 85-year-old man with advanced NSCLC with brain andbone metastasis was initially treated with gefitinib targeted therapy. After 4 months treatment, the patient developed drug resistance and a second genetic testing revealed that the T790M mutation was positive. And the patient was then changed to targeted therapy with osimertinib, followed by adverse reactions of varying severity such as diarrhea, electrolyte imbalance, decreased cardiac function, leukopenia, and prolonged QTc interval. Six months after the administration of osimertinib, the patient was admitted to the hospital, chest CT showed the lesion progressed again, and during which hospital-acquired infection occurred. After concomitant use of moxifloxacin, the patient had sudden TdP, and finally died of this cardiac event.

Conclusions

It is suggested that clinicians need to identify patients with high risk factors of TdP, and consider comprehensively in concomitant medication to avoid such events to the greatest extent.

Analysis of QTc Interval during Levofloxacin Prescription in Cardiac Patients with Pneumonia

Background:

Medications induced QT prolongation could cause ventricular arrhythmia, torsade de pointes, and death.

Objective:

The purpose of this study was to evaluate the magnitude of QTc interval prolongation as a result of levofloxacin treatment in patients admitted to cardiology wards.

Methods:

This was a cross-sectional study conducted in the coronary care units and general wards of the Imam Ali Heart Hospital in Kermanshah, Iran. The QTc interval was determined at baseline and after 72 hours of levofloxacin administration. Changes in the QTc interval before and after the levofloxacin prescription were determined.

Results:

The mean age of recruited patients was 63.26 ± 14.56 years. More than 80% of patients who received levofloxacin experienced QTc prolongation. The QTc interval was increased significantly after levofloxacin administration (15.68 ± 26.84 milliseconds) (p<0.001). These changes remained significant after excluding medications with QTc lengthening properties (p<0.001).

Conclusion:

Treatment with levofloxacin in patients with heart disease increases the risk of QT prolongation.

Cost of inappropriate antimicrobial use for upper respiratory infection in Japan

BACKGROUND

Antibiotics are often prescribed inappropriately to patients with upper respiratory infection (URI) in ambulatory care settings; however, the economic burden of such prescription has not been quantitatively assessed. Here, we aimed to evaluate the additional cost of antimicrobial prescription for URI at the population level in Japan.

METHODS

We conducted a retrospective observational survey using longitudinal claims data between 2013 and 2016 obtained from JMDC Claims Database, which contains data from 5·1 million corporate employees and family members under the age of 65 years. Appropriateness of antibiotic prescription was assessed by a panel of six infectious disease physicians according to ICD-10 code in JMDC Claims Database. Total additional cost of antibiotic prescription for URI at the national level was estimated by weighting of age-structured population data.

RESULTS

The annual additional cost of inappropriate antibiotic prescription for URI was estimated at 423·6 (95% CI: 416·8-430·5) million USD in 2013, 340·9 (95% CI: 335·7-346·2) million USD in 2014, 349·9 (95% CI: 344·5-355·3) million USD in 2015, and 297·1 (95% CI: 292·4-301·9) million USD in 2016. Three classes of broad-spectrum oral antibiotics (third-generation cephalosporins, macrolides, and fluoroquinolones) accounted for > 90% of the total additional cost.

CONCLUSIONS

Although a decreasing trend was observed, annual additional costs of inappropriate antibiotic prescriptions for URI could be a substantial economic burden in Japan. Appropriately prescribing broad-spectrum oral antibiotics might be an important issue to reduce unnecessary medical costs in Japanese ambulatory care.

Fluoroquinolones and Cardiovascular Risk: A Systematic Review, Meta-analysis and Network Meta-analysis

INTRODUCTION

Several fluoroquinolone antibiotics have been associated with cardiac adverse effects, leading to the withdrawal of some of these agents from the market. Cardiac side effects such as QT prolongation and torsades de pointes (TdP) have also been observed with fluoroquinolones currently on the market. In order to evaluate the cardiac risk of fluoroquinolones as a class, and the comparative risk for each individual drug, we conducted a systematic review, meta-analysis, and network meta-analysis.

METHODS

MEDLINE, EMBASE and the Cochrane Library were searched, up to March 2018, for randomized controlled trials, cohort studies, and case-control studies that investigated the association between fluoroquinolone treatment and the risk of cardiovascular events and cardiovascular mortality. We followed the PRISMA 2009 guidelines for data selection and extraction. Outcomes were pooled using random effects models. Direct and indirect comparisons in network meta-analysis were performed using frequentist methods.

RESULTS

Thirteen studies were included in our analyses. Fluoroquinolone use was associated with a statistically significant 85% increase in the risk for arrhythmia (odds ratio [OR] 1.85; 95% confidence interval [CI] 1.22-2.81) and 71% increase in the risk for cardiovascular mortality (OR 1.71; 95% CI 1.39-2.09). Moxifloxacin ranked most likely to have the highest risk for arrhythmia (P-score 0.99) and for cardiovascular mortality (P-score 0.95) by network meta-analysis.

CONCLUSIONS

Our findings show a significant association between fluoroquinolone use and an increased risk for arrhythmia and cardiovascular mortality. Moxifloxacin ranked with the highest probability for cardiovascular adverse events. Further study is required to determine how to reduce the risk for fluoroquinolone-associated cardiac toxicity.

Gatifloxacin Pharmacokinetics/Pharmacodynamics-based Optimal Dosing for Pulmonary and Meningeal Multidrug-resistant Tuberculosis

Background

Gatifloxacin is used for the treatment of multidrug-resistant tuberculosis (MDR-TB). The optimal dose is unknown.

Methods

We performed a 28-day gatifloxacin hollow-fiber system model of tuberculosis (HFS-TB) study in order to identify the target exposures associated with optimal kill rates and resistance suppression. Monte Carlo experiments (MCE) were used to identify the dose that would achieve the target exposure in 10000 adult patients with meningeal or pulmonary MDR-TB. The optimal doses identified were validated using probit analyses of clinical data from 2 prospective clinical trials of patients with pulmonary and meningeal tuberculosis. Classification and regression-tree (CART) analyses were used to identify the gatifloxacin minimum inhibitory concentration (MIC) below which patients failed or relapsed on combination therapy.

Results

The target exposure associated with optimal microbial kill rates and resistance suppression in the HFS-TB was a 0-24 hour area under the concentration-time curve-to-MIC of 184. MCE identified an optimal gatifloxacin dose of 800 mg/day for pulmonary and 1200 mg/day for meningeal MDR-TB, and a clinical susceptibility breakpoint of MIC ≤ 0.5 mg/L. In clinical trials, CART identified that 79% patients failed therapy if MIC was >2 mg/L, but 98% were cured if MIC was ≤0.5 mg/L. Probit analysis of clinical data demonstrated a >90% probability of a cure in patients if treated with 800 mg/day for pulmonary tuberculosis and 1200 mg/day for meningeal tuberculosis. Doses ≤400 mg/day were suboptimal.

Conclusions

Gatifloxacin doses of 800 mg/day and 1200 mg/day are recommended for pulmonary and meningeal MDR-TB treatment, respectively. Gatifloxacin has a susceptible dose-dependent zone at MICs 0.5-2 mg/L.

Cardiovascular safety of macrolide and fluoroquinolone antibiotics: An analysis of the WHO database of adverse drug reactions

INTRODUCTION

The cardiovascular safety profile of macrolides and fluoroquinolones has been widely discussed. The aim of the present study is to provide the contribution of real-world data onto the ongoing discussion about cardiovascular toxicity of both macrolides and fluoroquinolones.

METHODS

Reports of adverse drug reactions (ADRs) were retrieved from VigiBase. Macrolides and fluoroquinolones were compared with amoxicillin by using the reporting odds ratio (ROR) as a measure of disproportionality. Macrolides were then compared with fluoroquinolones.

RESULTS

Overall, 6810 reports of ADRs were retrieved: 62% of them were serious and 35% concerned female. Macrolides were more frequently associated with "atrial fibrillation" (ROR = 1.26, CI 1.02-1.57) and "ventricular fibrillation" ROR = 2.60, CI 1.92-3.54) than fluoroquinolones. Antimicrobials more frequently reported for "cardiac disorder" were azithromycin (375 reports) and clarithromycin (302) for macrolides and levofloxacin (470) and moxifloxacin (391) for fluoroquinolones.

CONCLUSION

Our data highlighted that macrolides and fluoroquinolones may influence cardiac rhythm and suggest caution in the prescribing of these drugs to patients with hidden cardiovascular risk factors. Although these ADRs seem to be not common, they have a notable impact in clinical practice because of the huge number of the exposed subjects.

BET 1: What is the incidence of cardiac arrhythmia in adult patients with acute infection prescribed fluoroquinolones?

A shortcut review was carried out to establish the incidence of arrhythmia after prescription of a fluoroquinolone antibiotic. 332 papers were found using the reported searches, of which 14 presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. It is concluded that the incidence of arrhythmia after prescription of a fluoroquinolone antibiotic is low (<3%), but estimates are imprecise.

Adverse Effects of Fluoroquinolones: A Retrospective Cohort Study in a South Indian Tertiary Healthcare Facility

The Food and Drug Administration (FDA) safety review revealed that the use of fluoroquinolones (FQs) is linked with disabling and potentially permanent serious adverse effects. These adverse effects compromise the tendons, muscles, joints, nerves, and central nervous system of the human body. The purpose of the study was to investigate the incidence and risk factors for adverse drug reactions (ADRs) caused by FQs in comparison with other antibiotics used. A retrospective cohort study was conducted over seven months in Kasturba Medical College Hospital, Manipal, India. Patients who were prescribed with FQs were selected as the study cohort (SC; n = 482), and those without FQs were the reference cohort (RC; n = 318). The results showed that 8.5% (41) of patients developed ADRs in the SC, whereas 4.1% (13) of patients developed ADRs in the RC. With oral and parenteral routes of administration, almost a similar number of ADRs were observed. Levofloxacin caused the highest number of ADRs reported, especially with the 750-mg dose. Based on a multiple logistic regression model, FQ use (odds ratio (OR): 2.27; 95% confidence interval (CI): 1.18-4.39; p = 0.015) and concomitant steroid use (OR: 3.19; 95% CI: 1.31-7.79; p = 0.011) were identified as independent risk factors for the development of ADRs among antibiotics users, whereas age was found to be protective (OR: 0.98; 95% CI: 0.97-1.00; p = 0.047). The study found a higher incidence of ADRs related to FQs compared to other antibiotics. The study concludes a harmful association between FQ use and the development of ADRs. Moreover, FQs are not safe compared to other antibiotics. Hence, the use of FQs should be limited to the conditions where no other alternatives are available.

Cardiac events after macrolides or fluoroquinolones in patients hospitalized for community-acquired pneumonia: post-hoc analysis of a cluster-randomized trial

Background

Guidelines recommend macrolides and fluoroquinolones in patients hospitalized with community-acquired pneumonia (CAP), but their use has been associated with cardiac events. We quantified associations between macrolide and fluoroquinolone use and cardiac events in patients hospitalized with CAP in non-ICU wards.

Methods

This was a post-hoc analysis of a cluster-randomized trial as a cohort study; including patients with a working diagnosis of CAP admitted to non-ICU wards without a cardiac event on admission. We calculated cause-specific hazard ratio’s (HR’s) for effects of time-dependent macrolide and fluoroquinolone exposure as compared to beta-lactam monotherapy on cardiac events, defined as new or worsening heart failure, arrhythmia, or myocardial ischemia during hospitalization.

Results

Cardiac events occurred in 146 (6.9%) of 2107 patients, including heart failure (n = 101, 4.8%), arrhythmia (n = 53, 2.5%), and myocardial ischemia (n = 14, 0.7%). These occurred in 11 of 207 (5.3%), 18 of 250 (7.2%), and 31 of 277 (11.2%) patients exposed to azithromycin, clarithromycin, and erythromycin for at least one day, and in 9 of 234 (3.8%), 5 of 194 (2.6%), and 23 of 566 (4.1%) exposed to ciprofloxacin, levofloxacin, and moxifloxacin, respectively. HR’s for erythromycin, compared to beta-lactam monotherapy, on any cardiac event and heart failure were 1.60 (95% CI 1.09;2.36) and 1.89 (95% CI 1.22;2.91), respectively. HR’s for levofloxacin and moxifloxacin, compared to beta-lactam monotherapy, on any cardiac event were 0.40 (95% CI 0.18;0.87)and 0.56 (95% CI 0.36;0.87), respectively. Findings remained consistent after adjustment for confounders and/or in a sensitivity analysis of radiologically confirmed CAP (n = 1604, 76.1%).

Conclusions

Among patients with CAP hospitalized to non-ICU wards, erythromycin use was associated with a 68% increased risk of hospital-acquired cardiac events, mainly heart failure. Levofloxacin and moxifloxacin were associated with a lower risk of heart failure. Although our study does not fully exclude confounding bias, findings remained largely unchanged in crude, adjusted, and sensitivity analyses. These findings may caution the use of erythromycin as empirical therapy in these patients.

Trial registration

The original trial was retrospectively registered under ClinicalTrials.gov Identifier NCT01660204 on August 8th, 2012.

Moxifloxacin-induced QT interval prolongation and torsades de pointes: a narrative review

INTRODUCTION

Moxifloxacin is widely used for the treatment of a number of infectious diseases because of its favorable pharmacological profile and high clinical success rate. However, it is often criticized for its higher risk of QTc interval prolongation (QTIP) and torsades de pointes (TdP).

AREAS COVERED

A review of published literature on moxifloxacin-related QTIP and TdP. Readers will be provided with a comprehensive overview of the prevalence, cellular mechanism, risk factors, and magnitude of QTIP of moxifloxacin.

EXPERT OPINION

In healthy subjects, moxifloxacin prolongs the QTc interval by 11.5-19.5 ms, it binds at the Tyr652 residue in the S6 pore domain of the human ether a-go-go gene related potassium channel. Considerable QTIP (30-60 ms) have also been reported in some patients, for instance the incidence of QTIP (30-60 ms) in elderly pneumonia patients was 15.5%. Moxifloxacin-induced QTIP may be of little clinical importance in healthy individuals. However, marked QTIP (>60 ms) and TdP have been reported in high-risk patients (patients who have multiple QT prolonging risk factors). Patients must be thoroughly assessed prior to the use of moxifloxacin and high-risk patients must be identified using risk assessment tools to ensure safe use of moxifloxacin and to safeguard patients' health.

Estimated Cardiac Risk Associated With Macrolides and Fluoroquinolones Decreases Substantially When Adjusting for Patient Characteristics and Comorbidities

BACKGROUND

Some studies have found that antimicrobials, especially macrolides, increase the risk of cardiovascular death. We investigated potential cardiac-related events associated with antimicrobial use in a population of patients with acute myocardial infarction.

METHODS AND RESULTS

For 185 010 Medicare beneficiaries, we recorded prescriptions for azithromycin, clarithromycin, levofloxacin, moxifloxacin, doxycycline, and amoxicillin-clavulanate. In the following week, we recorded death, acute myocardial infarction, atrial fibrillation or atrial flutter, a non-atrial fibrillation/atrial flutter arrhythmia, or ventricular arrhythmia. We fit unadjusted and adjusted logistic regression models using generalized estimating equations. Adjusted models included patients' comorbidities, medications, procedures, demographics, insurance status, time since index acute myocardial infarction, number of visits, and the influenza rate. In unadjusted analyses, macrolides and fluoroquinolones were associated with a risk of cardiac events. However, the risk associated with macrolide use was substantially attenuated after adjustment for a wide range of variables, and the risk associated with fluoroquinolones was no longer statistically significant. For example, for azithromycin, the odds ratio for any cardiac event or death was 1.35 (95% confidence interval, 1.27-1.44; P<0.0001), but after controlling for a wide range of covariates, the odds ratio decreased to 1.01 (95% confidence interval, 0.95-1.08; P<0.6688).

CONCLUSIONS

Controlling for covariates explains much of the adverse cardiac risk associated with antimicrobial use found in other studies. Most antimicrobials are not associated with risk of cardiac events, and others, specifically azithromycin and clarithromycin, may pose a small risk of certain cardiac events. However, the modest potential risks attributable to these antimicrobials must be weighed against the drugs' considerable and immediate benefits.

An optimized background regimen design to evaluate the contribution of levofloxacin to multidrug-resistant tuberculosis treatment regimens: study protocol for a randomized controlled trial

Background

Current guidelines for treatment of multidrug-resistant tuberculosis (MDR-TB) are largely based on expert opinion and observational data. Fluoroquinolones remain an essential part of MDR-TB treatment, but the optimal dose of fluoroquinolones as part of the regimen has not been defined.

Methods/design

We designed a randomized, blinded, phase II trial in MDR-TB patients comparing across levofloxacin doses of 11, 14, 17 and 20 mg/kg/day, all within an optimized background regimen. We assess pharmacokinetics, efficacy, safety and tolerability of regimens containing each of these doses. The primary efficacy outcome is time to culture conversion over the first 6 months of treatment. The study aims to determine the area under the curve (AUC) of the levofloxacin serum concentration in the 24 hours after dosing divided by the minimal inhibitory concentration of the patient’s Mycobacterium tuberculosis isolate that inhibits > 90% of organisms (AUC/MIC) that maximizes efficacy and the AUC that maximizes safety and tolerability in the context of an MDR-TB treatment regimen.

Discussion

Fluoroquinolones are an integral part of recommended MDR-TB regimens. Little is known about how to optimize dosing for efficacy while maintaining acceptable toxicity. This study will provide evidence to support revised dosing guidelines for the use of levofloxacin as part of combination regimens for treatment of MDR-TB. The novel methodology can be adapted to elucidate the effect of other single agents in multidrug antibiotic treatment regimens.

Trial registration

ClinicalTrials.gov, NCT01918397. Registered on 5 August 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2292-x) contains supplementary material, which is available to authorized users.

Fluoroquinolones increase the risk of serious arrhythmias: A systematic review and meta-analysis

BACKGROUND

The association between oral fluoroquinolones (FQs) usage and risk of severe arrhythmia-related events (ventricular arrhythmias and sudden cardiac death) remains controversial. Therefore we aimed to quantify this association and to evaluate the effects of FQs on adverse cardiovascular (CV) outcomes.

METHODS

We retrieved data from the Cochrane Collaboration, PubMed, and China National Knowledge Infrastructure (CNKI) databases until August 2017. The studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Data were extracted from the eligible articles, and we used a random effects model to calculate the effect estimates.

RESULTS

Of the 16 studies that were included, 7 studies included serious arrhythmias, 3 studies included CV death, and 11 studies included all-cause death. The pooled RRs of FQs use were: 2.29 (95% CI: 1.20-4.36, P = .01) for serious arrhythmias; 1.60 (95% CI: 1.17-2.20, P = .004) for CV death; and 1.02 (95% CI: 0.76-1.37, P = .92) for all-cause death. The RRs associated with serious arrhythmias were 6.27 for gatifloxacin, 4.20 for moxifloxacin, 1.73 for ciprofloxacin, and 1.41 for levofloxacin. Current FQs users showed an increased risk of serious arrhythmias in the subgroup analysis. Treatment with FQs is associated with an absolute risk increase of 160 additional sudden deaths or ventricular arrhythmias, and 43 additional CV deaths per 1 million treatment courses.

CONCLUSION

The use of FQs could increase the risk of serious arrhythmias and CV death but not increase or all-cause death. Moreover, moxifloxacin and levofloxacin showed a higher risk of serious arrhythmias.

Acute myeloid leukemia and the infectious diseases consultant

Infectious complications following treatment of acute myeloid leukemia (AML) are important causes of morbidity and mortality. The spectrum and complexity of these infections is reflected by the severe net state of immunosuppression of AML patients, that is dynamic and continuously changing, the polypharmacy, including the widespread use of anti-infectives and the complex epidemiology of severe and frequently resistant pathogens afflicting these patients. Infectious diseases (ID) consultants having a critical mass of expertise and intimate knowledge of the intricacies of leukemia care, add considerable value in improving outcomes of patients with AML who develop infections. Furthermore, pharmaco-economic considerations such as length of stay, choice of cost-effective anti-infective program, infection control and antibiotic stewardship strategies create a delicate interplay of the ID consultant and the ecosystem of care of AML patients. This is an increasingly recognized area of cross collaboration and a productive direction for future collaborative practice models and research.

Prevalence and Predictors of Postdischarge Antibiotic Use Following Mastectomy

OBJECTIVE Survey results suggest that prolonged administration of prophylactic antibiotics is common after mastectomy with reconstruction. We determined utilization, predictors, and outcomes of postdischarge prophylactic antibiotics after mastectomy with or without immediate breast reconstruction. DESIGN Retrospective cohort. PATIENTS Commercially insured women aged 18-64 years coded for mastectomy from January 2004 to December 2011 were included in the study. Women with a preexisting wound complication or septicemia were excluded. METHODS Predictors of prophylactic antibiotics within 5 days after discharge were identified in women with 1 year of prior insurance enrollment; relative risks (RR) were calculated using generalized estimating equations. RESULTS Overall, 12,501 mastectomy procedures were identified; immediate reconstruction was performed in 7,912 of these procedures (63.3%). Postdischarge prophylactic antibiotics were used in 4,439 procedures (56.1%) with immediate reconstruction and 1,053 procedures (22.9%) without immediate reconstruction (P.05). CONCLUSIONS Prophylactic postdischarge antibiotics are commonly prescribed after mastectomy; immediate reconstruction is the strongest predictor. Stewardship efforts in this population to limit continuation of prophylactic antibiotics after discharge are needed to limit antimicrobial resistance. Infect Control Hosp Epidemiol 2017;38:1048-1054.

Results of a local combination therapy antibiogram for Pseudomonas aeruginosa isolates: is double worth the trouble?

Purpose

To determine the frequency at which fluoroquinolones and aminoglycosides demonstrate in vitro activity against non-urinary, non-skin/skin structure Pseudomonas aeruginosa isolates exhibiting decreased susceptibilities to one or more β-lactam agents.

Methods

β-lactam-non-susceptible P. aeruginosa isolates recovered from blood, bone, lower respiratory tract, pleural fluid, cerebrospinal fluid, or peritoneal fluid cultures between October 2010 and October 2014 were reviewed from four community hospitals within a single health-system. Only the first isolate per patient was included for analysis. The likelihood that each isolate was susceptible to a non-β-lactam antimicrobial was then determined and summarized within a combination antibiogram.

Results

In total, 179 P. aeruginosa isolates with decreased susceptibilities to one or more β-lactam agents were assessed. Because no appreciable differences in antimicrobial susceptibility profile were observed between hospitals, the isolates were evaluated in aggregate. Susceptibility rates for β-lactam monotherapy ranged from 34% to 75%. Aminoglycosides possessed increased antibacterial activity compared to fluoroquinolones. Tobramycin was the non-β-lactam most likely to expand antimicrobial coverage against β-lactam-non-susceptible P. aeruginosa with activity against 64%, 66%, and 65% of cefepime-, piperacillin-tazobactam-, and meropenem-non-susceptible isolates, respectively (p < 0.001 for all).

Conclusions

The results of this study support the use of aminoglycosides over fluoroquinolones for achieving optimal, empiric antimicrobial combination therapy for P. aeruginosa when dual antimicrobial therapy is clinically necessary. Future efforts aimed at optimizing combination therapy for P. aeruginosa should focus on systemic interventions that limit the selection of fluoroquinolones in combination with β-lactams to expand coverage based on local susceptibility rates.

Patient Report and Review of Rapidly Growing Mycobacterial Infection after Cardiac Device Implantation

As more of these devices are implanted, such infections are likely to be more frequently reported.

Mycobacterial infections resulting from cardiac implantable electronic devices are rare, but as more devices are implanted, these organisms are increasingly emerging as causes of early-onset infections. We report a patient with an implantable cardioverter-defibrillator pocket and associated bloodstream infection caused by an organism of the Mycobacterium fortuitum group, and we review the literature regarding mycobacterial infections resulting from cardiac device implantations. Thirty-two such infections have been previously described; most (70%) were caused by rapidly growing species, of which M. fortuitum group species were predominant. When managing such infections, clinicians should consider the potential need for extended incubation of routine cultures or dedicated mycobacterial cultures for accurate diagnosis; combination antimicrobial drug therapy, even for isolates that appear to be macrolide susceptible, because of the potential for inducible resistance to this drug class; and the arrhythmogenicity of the antimicrobial drugs traditionally recommended for infections caused by these organisms.

Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology

The delayed reporting of antimicrobial susceptibility testing remains a limiting factor in clinical decision-making in the treatment of bacterial infection. This study evaluates the use of forward laser light scatter (FLLS) to measure bacterial growth for the early determination of antimicrobial susceptibility. Three isolates each (two clinical isolates and one reference strain) of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were tested in triplicate using two commercial antimicrobial testing systems, the Vitek2 and the MicroScan MIC panel, to challenge the BacterioScan FLLS. The BacterioScan FLLS showed a high degree of categorical concordance with the commercial methods. Pairwise comparison with each commercial system serving as a reference standard showed 88.9% agreement with MicroScan (two minor errors) and 72.2% agreement with Vitek (five minor errors). FLLS using the BacterioScan system shows promise as a novel method for the rapid and accurate determination of antimicrobial susceptibility.

Systematic review of loperamide: No proof of antibiotics being superior to loperamide in treatment of mild/moderate travellers' diarrhoea

Looking at the worldwide emergency of antimicrobial resistance, international travellers appear to have a central role in spreading the bacteria across the globe. Travellers' diarrhoea (TD) is the most common disease encountered by visitors to the (sub)tropics. Both TD and its treatment with antibiotics have proved significant independent risk factors of colonization by resistant intestinal bacteria while travelling. Travellers should therefore be given preventive advice regarding TD and cautioned about taking antibiotics: mild or moderate TD does not require antibiotics. Logical alternatives are medications with effects on gastrointestinal function, such as loperamide. The present review explores literature on loperamide in treating TD. Adhering to manufacturer's dosage recommendations, loperamide offers a safe and effective alternative for relieving mild and moderate symptoms. Moreover, loperamide taken singly does no predispose to contracting MDR bacteria. Most importantly, we found no proof that would show antibiotics to be significantly more effective than loperamide in treating mild/moderate TD.

Off-label use of oral fluoroquinolone antibiotics in outpatient settings in the United States, 2006 to 2012

PURPOSE

The aim of this study was to evaluate the practice pattern of off-label use of fluoroquinolones (FQs) in ambulatory settings and to identify the related risk factors.

METHODS

The National Ambulatory Medical Care Surveys from 2006 through 2012 was used to identify subjects who received FQ off-label prescriptions. We defined off-label use as the use of FQs for indications other than those in the FDA-approved drug label. Descriptive statistics were calculated by using a series of weighted chi-squared statistics. Multivariate logistic regression was conducted to identify factors associated with off-label FQ drug use.

RESULTS

There were 93 million ambulatory visits in which an FQ was prescribed, and 53.16% of these visits involved the prescribing of FQs in an off-label manner. The percentage of off-label prescriptions was the highest among individuals ≥80 years old (61.6%) and male patients (60.9%). The FQ drug prescribed most for an off-label indication in our study was ciprofloxacin (29.5% of the total visits). The multivariate analysis showed that age of ≥80 years and male patient was significantly associated with off-label use of FQs (adjusted odds ratio (OR) 3.66, 1.72-7.80 and OR 3.26, 2.32-4.56, respectively). Medicaid or private insurance versus Medicare were associated with significantly higher off-label prescribing of FQs (OR 2.53, 1.28-5.01 and 1.77, 1.03-3.03, respectively).

CONCLUSION

The percentage of visits involving off-label FQs in US ambulatory settings is substantial. Efforts are needed consolidate and evaluate what high-quality scientific evidence is available and what is needed to support the safety and effectiveness of such off-label uses. Copyright © 2016 John Wiley & Sons, Ltd.

Incidence of Sustained Ventricular Tachycardia in Patients with Prolonged QTc After the Administration of Azithromycin: A Retrospective Study

Background

Azithromycin has been associated with abnormalities of cardiac repolarization and development of torsades de pointes. Observational data suggest that the risk of death from cardiovascular causes is increased in patients taking azithromycin. Little is known regarding the risk of ventricular arrhythmia in patients with prolongation of the corrected QT interval who receive azithromycin.

Objective

The purpose of this study was to determine the incidence of sustained ventricular tachycardia in patients with prolonged corrected QT (QTc) who subsequently received azithromycin.

Methods

We performed a retrospective cohort analysis of the incidence of sustained ventricular tachycardia in patients with prolonged QTc (greater than 450 ms) who successively received intravenous (IV) and/or oral azithromycin. Patients hospitalized in a tertiary care teaching hospital between November 2009 and June 2012 were included in the study. The primary outcome was sustained ventricular tachycardia documented in patients on telemetry.

Results

Of the 103 patients enrolled in the study, only one patient experienced the primary outcome (0.97 %). The event occurred 1 day after the administration of a single dose of 500 mg IV azithromycin.

Conclusion

The risk of sustained ventricular tachycardia was 0.97 % in our cohort of patients with prolonged QTc who subsequently received azithromycin. Given the small size of this study, additional research is needed to determine the true incidence of arrhythmia in the population.

Oral fluoroquinolone use and serious arrhythmia: bi-national cohort study

OBJECTIVE

To evaluate if oral fluoroquinolone use is associated with an increased risk of serious arrhythmia.

DESIGN

Bi-national cohort study, linking register data on filled prescriptions, cases of serious arrhythmia, and patient characteristics.

SETTING

Denmark, 1997-2011; Sweden, 2006-13.

PARTICIPANTS

The study cohort was derived from a source population of all Danish and Swedish adults, aged 40 to 79 years. 909,656 courses of fluoroquinolone use (ciprofloxacin 82.6%, norfloxacin 12.1%, ofloxacin 3.2%, moxifloxacin 1.2%, and other fluoroquinolones 0.9%) and 909,656 courses of penicillin V use, matched 1:1 on propensity score, were included.

MAIN OUTCOME MEASURE

The main outcome was risk of serious arrhythmia (fatal and non-fatal), comparing courses of fluoroquinolone use with courses of penicillin V use (an antibiotic with no pro-arrhythmic effect). The risk period of interest was current use, defined as days 0-7 of treatment. Subgroup analyses were conducted according to country, sex, age, underlying cardiovascular disease, concomitant use of drugs known to increase the risk of torsades de pointes, fluoroquinolone type, and levels of arrhythmia risk score.

RESULTS

144 cases of serious arrhythmia occurred during follow-up, 66 among current fluoroquinolone users (incidence rate 3.4 per 1000 person years) and 78 among current penicillin users (4.0 per 1000 person years); comparing oral fluoroquinolone treatment with penicillin V, the rate ratio was 0.85 (95% confidence interval 0.61 to 1.18). Compared with penicillin V, the absolute risk difference was -13 (95% confidence interval -35 to 16) cases of serious arrhythmia per 1,000,000 courses of fluoroquinolones. The risk of serious arrhythmia was not statistically significantly increased in any of the subgroups, including analyses by fluoroquinolone type.

CONCLUSIONS

Contrary to previous reports, oral fluoroquinolone treatment was not associated with an increased risk of serious arrhythmia in the general adult populations of Denmark and Sweden. Given the statistical power of the study, even small increases in relative and absolute risk could be ruled out. Since ciprofloxacin was the most commonly used fluoroquinolone in our study, we cannot exclude that intraclass differences influence the risk of serious arrhythmia associated with other less frequently used fluoroquinolones.

Safety and tolerability profile of second-line anti-tuberculosis medications

Tuberculosis (TB) remains a major public health problem, representing the second leading cause of death from infectious diseases globally, despite being nearly 100 % curable. Multidrug-resistant (MDR)-TB, a form of TB resistant to isoniazid and rifampicin (rifampin), two of the key first-line TB drugs, is becoming increasingly common. MDR-TB is treated with a combination of drugs that are less effective but more toxic than isoniazid and rifampicin. These drugs include fluoroquinolones, aminoglycosides, ethionamide, cycloserine, aminosalicyclic acid, linezolid and clofazimine among others. Minor adverse effects are quite common and they can be easily managed with symptomatic treatment. However, some adverse effects can be life-threatening, e.g. nephrotoxicity due to aminoglycosides, cardiotoxicity due to fluoroquinolones, gastrointestinal toxicity due to ethionamide or para-aminosalicylic acid, central nervous system toxicity due to cycloserine, etc. Baseline evaluation may help to identify patients who are at increased risk for adverse effects. Regular clinical and laboratory evaluation during treatment is very important to prevent adverse effects from becoming serious. Timely and intensive monitoring for, and management of adverse effects caused by, second-line drugs are essential components of drug-resistant TB control programmes; poor management of adverse effects increases the risk of non-adherence or irregular adherence to treatment, and may result in death or permanent morbidity. Treating physicians should have a thorough knowledge of the adverse effects associated with the use of second-line anti-TB drugs, and routinely monitor the occurrence of adverse drug reactions. In this review, we have compiled safety and tolerability information regarding second-line anti-TB drugs in both adults and children.

Rare Incidence of Ventricular Tachycardia and Torsades de Pointes in Hospitalized Patients With Prolonged QT Who Later Received Levofloxacin: A Retrospective Study

OBJECTIVE

To determine the incidence of ventricular tachycardia and ventricular fibrillation in patients with prolonged corrected QT interval (QTc) who received levofloxacin through retrospective chart review at a tertiary care teaching hospital in the United States.

PATIENTS AND METHODS

We selected 1004 consecutive hospitalized patients with prolonged QTc (>450 ms) between October 9, 2009 and June 12, 2012 at our institution. Levofloxacin was administered orally and/or intravenously and adjusted to renal function in the inpatient setting. The primary outcome measure was sustained ventricular tachycardia recorded electrocardiographically.

RESULTS

With a median time from the start of levofloxacin use to hospital discharge (or death) of 4 days (range, 1-94 days), only 2 patients (0.2%; 95% CI, 0.0%-0.7%) experienced the primary outcome of sustained ventricular tachycardia after the initiation of levofloxacin use.

CONCLUSION

In this study, the short-term risk for sustained ventricular tachycardia in patients with a prolonged QTc who subsequently received levofloxacin was very rare. These results suggest that levofloxacin may be a safe option in patients with prolonged QTc; however, studies with longer follow-up are needed.

Moxifloxacin pharmacokinetic profile and efficacy evaluation in empiric treatment of community-acquired pneumonia

When antimicrobials are used empirically, pathogen MICs equal to clinical breakpoints or epidemiological cutoff values must be considered. This is to ensure that the most resistant pathogen subpopulation is appropriately targeted to prevent emergence of resistance. Accordingly, we determined the pharmacokinetic (PK) profile of moxifloxacin at 400 mg/day in 18 patients treated empirically for community-acquired pneumonia. We developed a population pharmacokinetic model to assess the potential efficacy of moxifloxacin and to simulate the maximal MICs for which recommended pharmacokinetic-pharmacodynamic (PK-PD) estimates are obtained. Moxifloxacin plasma concentrations were determined the day after therapy initiation using ultra-high-performance liquid chromatography. Peak drug concentrations (Cmax) and area under the free drug concentration-time curve from 0 to 24 h (fAUC0-24) values predicted for each patient were evaluated against epidemiological cutoff MIC values for Streptococcus pneumoniae, Haemophilus influenzae, and Legionella pneumophila. PK-PD targets adopted were a Cmax/MIC of ≥12.2 for all pathogens, an fAUC0-24/MIC of >34 for S. pneumoniae, and an fAUC0-24/MIC of >75 for H. influenzae and L. pneumophila. Individual predicted estimates for Cmax/MIC and fAUC0-24/MIC as well as simulated maximal MICs resulting in target attainment for oral and intravenous administration of the drug were suitable for S. pneumoniae and H. influenzae but not for L. pneumophila. These results indicate that caution must be taken when moxifloxacin is used as monotherapy to treat community-acquired pneumonia caused by L. pneumophila. In conclusion, this report reveals key information relevant to the empirical treatment of community-acquired pneumonia while highlighting the robust and flexible nature of this population pharmacokinetic model to predict therapeutic success. (Clinical Trials Registration no. NCT01983839.).

Risks of cardiac arrhythmia and mortality among patients using new-generation macrolides, fluoroquinolones, and β-lactam/β-lactamase inhibitors: a Taiwanese nationwide study

BACKGROUND

Previous studies have demonstrated increased cardiovascular mortality related to azithromycin and levofloxacin. Risks associated with alternative drugs in the same class, including clarithromycin and moxifloxacin, were unknown. We used the Taiwan National Health Insurance Database to perform a nationwide, population-based study comparing the risks of ventricular arrhythmia and cardiovascular death among patients using these antibiotics.

METHODS

Between January 2001 and November 2011, a total of 10 684 100 patients were prescribed oral azithromycin, clarithromycin, moxifloxacin, levofloxacin, ciprofloxacin, or amoxicillin-clavulanate at outpatient visits. A logistic regression model adjusted for propensity score was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for adverse cardiac outcomes occurring within 7 days after the initiation of antibiotic treatment.

RESULTS

Compared with amoxicillin-clavulanate treatment, the use of azithromycin and moxifloxacin was associated with significant increases in the risks of ventricular arrhythmia and cardiovascular death. The adjusted ORs for ventricular arrhythmia were 4.32 (95% CI, 2.95-6.33) for azithromycin, 3.30 (95% CI, 2.07-5.25) for moxifloxacin, and 1.41 (95% CI, .91-2.18) for levofloxacin. For cardiovascular death, the adjusted ORs for azithromycin, moxifloxacin, and levofloxacin were 2.62 (95% CI, 1.69-4.06), 2.31 (95% CI, 1.39-3.84), and 1.77 (95% CI, 1.22-2.59), respectively. No association was noted between clarithromycin or ciprofloxacin and adverse cardiac outcomes.

CONCLUSIONS

Healthcare professionals should consider the small but significant increased risk of ventricular arrhythmia and cardiovascular death when prescribing azithromycin and moxifloxacin. Additional research is needed to determine whether the increased risk of mortality is caused by the drugs or related to the severity of infection or the pathogens themselves.

Germs are germs, and why not take a risk? Patients' expectations for prescribing antibiotics in an inner-city emergency department

BACKGROUND

. Extensive use of unnecessary antibiotics has driven the emergence of resistant bacterial strains, posing a threat to public health. Physicians are more likely to prescribe antibiotics when they believe that patients expect them. Current attempts to change these expectations highlight the distinction between viruses and bacteria ("germs are germs"). Fuzzy-trace theory further predicts that patients expect antibiotics because they make decisions based on categorical gist, producing strategies that encourage risk taking when the status quo is bad (i.e., "why not take a risk?"). We investigate both hypotheses.

METHODS

. We surveyed patients visiting the emergency department of a large urban hospital (72 [64%] were African American) using 17 Likert scale questions and 2 free-response questions regarding patient expectations for antibiotics.

RESULTS

. After the clinical encounter, 113 patients completed the survey. Fifty-four (48%) patients agreed with items that assess the "germs are germs" hypothesis, whereas 86 (76%) agreed with items that assess the "why not take a risk?" hypothesis. "Why not take a risk?" captures significant unique variance in a factor analysis and is neither explained by "germs are germs" nor by patients' lack of knowledge regarding side effects. Of the 81 patients who rejected the "germs are germs" hypothesis, 61 (75%) still indicated agreement with the "why not take a risk?" hypothesis. Several other misconceptions were also investigated.

CONCLUSIONS

. Our findings suggest that recent public health campaigns that have focused on educating patients about the differences between viruses and bacteria omit a key motivation for why patients expect antibiotics, supporting fuzzy-trace theory's predictions about categorical gist. The implications for public health and emergency medicine are discussed.

Orofacial dyskinesia associated with the use of levofloxacin

OBJECTIVE

To describe a case of orofacial dyskinesia in a patient treated with levofloxacin for acute diverticulitis.

CASE SUMMARY

A 77-year-old woman with mild renal insufficiency was admitted with acute diverticulitis. She was initiated on levofloxacin 500 mg IV daily and metronidazole 500 mg IV every 8 hours. On day 4 of treatment, she experienced involuntary, rhythmic facial grimacing accompanied by periodic cervical muscular contractures. Her speech became dysarthric, interrupted by uncontrolled facial and tongue movements, all findings consistent with orofacial dyskinesia. Antibiotics were discontinued, and symptoms resolved after administration of diphenhydramine and lorazepam IV.

DISCUSSION

Fluoroquinolone-associated central nervous system (CNS) toxicities are infrequently observed. They are most commonly associated with ciprofloxacin and are thought to be related to inhibition of γ-aminobutyric acid receptors and activation of N-methyl-d-aspartate receptors. Orofacial dyskinesia has previously been reported primarily with second-generation fluoroquinolones, with only a single case report implicating a third-generation fluoroquinolone. To our knowledge, we report the second case of orofacial dyskinesia with a third-generation fluoroquinolone, the first such case associated with levofloxacin. The orofacial dyskinesia experienced in this case was categorized as probably related to levofloxacin, as assessed by the Naranjo adverse drug reaction probability assessment tool. Contributing factors likely included age and renal function.

CONCLUSIONS

Although rare, CNS toxicities such as orofacial dyskinesia have been reported with levofloxacin. Patients on fluoroquinolones of advanced age and with renal insufficiency should be monitored closely for such toxicities.

A Review of the Evidence for Using Bedaquiline (TMC207) to Treat Multi-Drug Resistant Tuberculosis

Existing therapies for multi-drug resistant tuberculosis (MDR-TB) have substantial limitations, in terms of their effectiveness, side-effect profile, and complexity of administration. Bedaquiline is a novel diarylquinoline antibiotic that has recently been investigated as an adjunct to existing therapies for MDR-TB. Currently, limited clinical data are available to evaluate the drug’s safety and effectiveness. In two small randomized-controlled clinical studies, bedaquiline given for 8 or 24 weeks has been shown to improve surrogate microbiological markers of treatment response, but trials have not yet evaluated its impact on clinical failure and relapse. Safety concerns include an increased mortality in the bedaquiline arm of one study, an increased incidence of QT segment prolongation on electrocardiogram, and hepatotoxicity. Until further research data are available, the use of bedaquiline should be confined to settings where carefully selected patients can be closely monitored.

Complications of antibiotic therapy

Antibiotics have greatly changed the practice of medicine for the better. Many infections commonly treated in the outpatient setting with antibiotics (eg, urinary tract infections, streptococcal pharyngitis), which previously caused significant morbidity and mortality, are now typically benign. However, with antibiotic therapy come side effects, ranging in severity from mild nausea to life-threatening cytopenias. This article highlights important complications of antibiotic therapy that may be encountered by outpatient providers. Side effects by system are discussed, and a few important drug-specific complications and important drug-drug interactions highlighted.