Effect of ciprofloxacin and levofloxacin on the QT interval: is this a significant "clinical" event?

Preliminary human health risk assessment of antibiotic exposures in human waste handling occupations

Exposure to biosolids in human waste handling occupations is associated with a risk for illness due to microbial infections. Although several years of exposure to biosolids might be hypothesized to be a prophylaxis against infection, the risks associated with infections from antibiotic-resistant organisms can also be a potential concern. Therefore, this study aimed to conduct a screening level risk assessment by deriving occupational exposure limits (OELs) characterizing the risks of adverse health effects among workers in human waste handling occupations with a focus on exposure to two pharmaceuticals commonly found in biosolids: ciprofloxacin (CIP) and azithromycin (AZ). Epidemiological and exposure studies of workers exposed to biosolids were identified through searches of major scientific databases. Screening OELs (sOELs) for these antibiotics were derived using a standardized methodology. The airborne concentrations of CIP and AZ antibiotics were determined using an exposure factors approach. The health-based exposure limits (i.e., sOELs) and the acceptable daily exposure (ADE) values for both of these antibiotics were derived as 80 μg/m3 and 12 μg/kg-day, respectively. An exposure factor approach suggested that inhalation route exposures to CIP and AZ are well below the sOELs and ADE daily doses, and likely too low to cause direct adverse health effects through antibiotic inhalation. A critical review of epidemiological studies on different occupations handling biosolids showed that the workers in industries with potential biosolids exposure have experienced an increased incidence of microbial-exposure-related illness. The health effects seen in the workers have been attributed to bacterial, viral, and protozoan infections. To the extent that bacteria are the pathogen of concern, it is not clear whether these bacteria are resistant to antibiotics commonly found in biosolids. It is also unclear whether the presence of antibiotics or antibiotic-resistant bacteria increases the susceptibility of these workers. Additional studies will provide more definitive estimates of inhalation and dermal exposures to CIP and AZ and could verify the exposure estimates in this study based on the literature and common exposure factors.

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.

Drug Utilization Evaluation Study of Ciprofloxacin Use and Adverse Events Occurrence: Role of Community Pharmacists

Background: Antimicrobial resistance is a global health crisis threatening optimal management of infectious diseases. Ciprofloxacin is a widely used fluoroquinolone in various disease conditions. Resistance against ciprofloxacin is increasing, leading to nonoptimal management of patients. Thus, the aim of this study was to assess ciprofloxacin use in the community setting in terms of appropriate prescribing, dosing, frequency, and duration of use. Methods: A cross-sectional, retrospective study was conducted by community pharmacists in 5 community pharmacies in Egypt from September 2021 to February 2022. Patients prescribed oral ciprofloxacin during the period of the study were included. Data on demographics, indications for ciprofloxacin, dosing regimen, adverse events, and drug interactions were collected. Results: A total of 151 patients' record indicated for ciprofloxacin were included in the study, of whom 44.4% were men and 55.6% were women who were neither pregnant nor lactating. Based on international guidelines, 96.69% ciprofloxacin prescriptions were appropriate; 96.03% contained correct ciprofloxacin dosing whereas 3.97% were overdose. A total of 90. 73% had correct frequency of administration and 96.03% records had correct durations. Only 1.99% of patients were ≤18 years of age, which is an absolute contraindication. Interacting drugs with ciprofloxacin were 28.5% with acetaminophen, 31.1% with ibuprofen, 16.6% with antacids, 21.2% with chlorpheniramine, and 7.9% with prednisolone. Adverse events included 1.32% hypoglycemia, 0.66% hyperglycemia, 3.97% tendinitis, and 2.65% QTc (heart rate-corrected QT interval) prolongation. Conclusion and relevance: Ciprofloxacin use in community pharmacies is appropriate according to international guidelines. Ongoing drug utilization evaluation is necessary to ensure rational drug use, which in turn can decrease resistance rates.

Serial electrocardiogram recordings revealed a high prevalence of QT interval prolongation in patients with tuberculosis receiving fluoroquinolones

BACKGROUND

Fluoroquinolones, crucial components of treatment regimens for drug-resistant tuberculosis (TB), are associated with QT interval prolongation and risks of fatal cardiac arrhythmias. However, few studies have explored dynamic changes in the QT interval in patients receiving QT-prolonging agents.

METHODS

This prospective cohort study recruited hospitalized patients with TB who received fluoroquinolones. The study investigated the variability of the QT interval by using serial electrocardiograms (ECGs) recorded four times daily. This study analyzed the accuracy of intermittent and single-lead ECG monitoring in detecting QT interval prolongation.

RESULTS

This study included 32 patients. The mean age was 68.6 ± 13.2 years. The results revealed mild-to-moderate and severe QT interval prolongation in 13 (41%) and 5 (16%) patients, respectively. The incremental yields in sensitivity of one to four daily ECG recordings were 61.0%, 26.1%, 5.6%, and 7.3% in detecting mild-to-moderate QT interval prolongation, and 66.7%, 20.0%, 6.7%, and 6.7% in detecting severe QT interval prolongation. The sensitivity levels of lead II and V5 ECGs in detecting mild-to-moderate and severe QT interval prolongation exceeded 80%, and their specificity levels exceeded 95%.

CONCLUSION

This study revealed a high prevalence of QT interval prolongation in older patients with TB who receive fluoroquinolones, particularly those with multiple cardiovascular risk factors. Sparsely intermittent ECG monitoring, the prevailing strategy in active drug safety monitoring programs, is inadequate owing to multifactorial and circadian QT interval variability. Additional studies performing serial ECG monitoring are warranted to enhance the understanding of dynamic QT interval changes in patients receiving QT-prolonging anti-TB agents.

Antipsychotic Polypharmacy-Related Cardiovascular Morbidity and Mortality: A Comprehensive Review

Schizophrenia is a psychotic disorder that exists at the more extreme end of a spectrum of diseases, and significantly affects daily functioning. Cardiovascular adverse effects of antipsychotic medications are well known, and include changes in blood pressure and arrhythmias. Sudden cardiac death is the leading cause of death worldwide, and antipsychotic medications are associated with numerous cardiac side effects. A possible link exists between antipsychotic medications and sudden cardiac death. Common prescribing patterns that may influence cardiovascular events include the use of multiple antipsychotics and/or additional drugs commonly prescribed to patients on antipsychotics. The results of this review reflect an association between antipsychotic drugs and increased risk of ventricular arrhythmias and sudden cardiac death by iatrogenic prolongation of the QTc interval. QTc prolongation and sudden cardiac death exist in patients taking antipsychotic monotherapy. The risk increases for the concomitant use of specific drugs that prolong the QTc interval, such as opioids, antibiotics, and illicit drugs. However, evidence suggests that QTc intervals may not adequately predict sudden cardiac death. In considering the findings of this narrative review, we conclude that it is unclear whether there is a precise association between antipsychotic polypharmacy and sudden cardiac death with QTc interval changes. The present narrative review warrants further research on this important potential association.

Dynamics of the QTc interval over a 24-h dose interval after start of intravenous ciprofloxacin or low-dose erythromycin administration in ICU patients

QTc interval prolongation is an adverse effect associated with the use of fluoroquinolones and macrolides. Ciprofloxacin and erythromycin are both frequently prescribed QTc-prolonging drugs in critically ill patients. Critically ill patients may be more vulnerable to developing QTc prolongation, as several risk factors can be present at the same time. Therefore, it is important to know the QTc-prolonging potential of these drugs in the intensive care unit (ICU) population. The aim of this study was to assess the dynamics of the QTc interval over a 24-hour dose interval during intravenous ciprofloxacin and low-dose erythromycin treatment. Therefore, an observational study was performed in ICU patients (≥18 years) receiving ciprofloxacin 400 mg t.i.d. or erythromycin 100 mg b.i.d. intravenously. Continuous ECG data were collected from 2 h before to 24 h after the first administration. QT-analyses were performed using high-end holter software. The effect was determined with a two-sample t-test for clustered data on all QTc values. A linear mixed model by maximum likelihood was applied, for which QTc values were assessed for the available time intervals and therapy. No evident effect over time on therapy with ciprofloxacin and erythromycin was observed on QTc time. There was no significant difference (p = 0.22) in QTc values between the ciprofloxacin group (mean 393 ms) and ciprofloxacin control group (mean 386 ms). The erythromycin group (mean 405 ms) and erythromycin control group (mean 404 ms) neither showed a significant difference (p = 0.80). In 0.6% of the registrations (1.138 out of 198.270 samples) the duration of the QTc interval was longer than 500 ms. The index groups showed slightly more recorded QTc intervals over 500 ms. To conclude, this study could not identify differences in the QTc interval between the treatments analyzed.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Effect of triple antimicrobial therapy on electrocardiography parameters in patients with mild-to-moderate coronavirus disease 2019

OBJECTIVE

The effects of treatment of coronavirus disease 2019 (COVID-19) with a triple combination composed of hydroxychloroquine, an an-tiviral, and an antibiotic on electrocardiography (ECG) parameters in patients with mild-to-moderate symptoms are not wholly understood. We aimed to explore the changes in ECG parameters after treatment with triple combination therapy in patients with mild-to-moderate symptomatic COVID-19.

METHODS

This retrospective, single-center case series analyzed 91 patients with mild-to-moderate symptomatic COVID-19 at Ankara Gazi Mus-tafa Kemal State Hospital of Ankara City, Turkey, from April 1, 2020, to April 30, 2020. Forty-three patients were treated with hydroxychloroquine+oseltamivir+azithromycin (Group 1) and 48 patients were treated with hydroxychloroquine+oseltamivir+levofloxacin (Group 2). Heart rate, P wave duration, P wave dispersion, PR interval, QRS duration, corrected QT interval (QTc), QTc dispersion (QTD), delta QTc, Tp-e, Tp-e dispersion, and Tp-e/QTc ratio were all calculated from the baseline and posttreatment 12-lead ECG recordings.

RESULTS

The QTc, QRS duration, Tp-e, PR interval, and P wave duration were significantly increased after treatment (p<0.001; p<0.001; p<0.001; p=0.001; p=0.001). The posttreatment C-reactive protein level was significantly lower than at baseline in Group 1 (p=0.014). At admission, 30% of patients had QT prolongation, and 4.3% of them had a QT duration >500 ms. Both Group 1 and Group 2 showed significant prolongation of the QTc interval (Group 1; p<0.001 vs. Group 2; p<0.001), QRS duration (Group 1; p=0.006 vs. Group 2; p=0.014), Tp-e (Group 1; p=0.036 vs. Group 2; p<0.001), and PR interval (Group 1; p=0.002 vs. Group2; p=0.05). The QTD was significantly decreased in Group 1 (p<0.001). None of the patients experienced any overt ventricular arrhythmia.

CONCLUSION

To the best of our knowledge, this study is the first to investigate QT prolongation in a population of COVID-19 patients treated with triple combination therapy. We found that there was a significant decrease in the QTD after the treatment in patients who were taking triple therapy including azithromycin.

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.

V. Kumar A, Ramaswamy G, Htun T, Thanh Hoang Thi T, Hoai Nguyen G, Quelapio M, Gebhard A, Nguyen HB, Nguyen NV. High Levels of Treatment Success and Zero Relapse in Multidrug-Resistant Tuberculosis Patients Receiving a Levofloxacin-Based Shorter Treatment Regimen in Vietnam

Vietnam has been using a levofloxacin-based shorter treatment regimen (STR) for rifampicin resistant/multidrug-resistant tuberculosis (RR/MDR-TB) patients since 2016 on a pilot basis. This regimen lasts for 9–11 months and is provided to RR/MDR-TB patients without second-line drug resistance. We report the treatment outcomes and factors associated with unsuccessful outcomes. We conducted a cohort study involving secondary analysis of data extracted from electronic patient records maintained by the national TB program (NTP). Of the 302 patients enrolled from April 2016 to June 2018, 259 (85.8%) patients were successfully treated (246 cured and 13 ‘treatment completed’). Unsuccessful outcomes included: treatment failure (16, 5.3%), loss to follow-up (14, 4.6%) and death (13, 4.3%). HIV-positive TB patients, those aged ≥65 years and patients culture-positive at baseline had a higher risk of unsuccessful outcomes. In a sub-group of patients enrolled in 2016 (n = 99) and assessed at 12 months after treatment completion, no cases of relapse were identified. These findings vindicate the decision of the Vietnam NTP to use a levofloxacin-based STR in RR/MDR-TB patients without second-line drug resistance. This regimen may be considered for nationwide scale-up after a detailed assessment of adverse drug events.

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.

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.

Cardiac risks associated with antibiotics: azithromycin and levofloxacin

INTRODUCTION

Azithromycin and levofloxacin have been shown to be efficacious in treating infections. The adverse drug events associated with azithromycin and levofloxacin were considered rare. However, the US FDA released warnings regarding the possible risk of QT prolongation with azithromycin and levofloxacin.

AREAS COVERED

Case reports/case series, observational studies and clinical trials assessing cardiovascular risks associated with azithromycin and levofloxacin were critically reviewed, including 15 case reports/series, 5 observational studies and 5 clinical trials that investigated the cardiac risks associated azithromycin and levofloxacin.

EXPERT OPINION

Results are discordant. Two retrospective studies utilizing large databases demonstrated an increased risk of cardiovascular death with azithromycin, when azithromycin was compared with amoxicillin. Two other retrospective studies found no difference in cardiovascular death associated with azithromycin and other antibiotics. For levofloxacin, the increased risk of cardiovascular death was only found in one retrospective study. Therefore, the risks and benefits of antibacterial therapies should be considered when making prescription decisions. This study should not preclude clinicians from avoiding azithromycin and levofloxacin. If a patient has an indication to receive an antibiotic and if azithromycin or levofloxacin is needed, it may be used, but the potential risks must be understood.

The use of fluoroquinolones in children: recent advances

Fluoroquinolones are an important group of antibiotics that are used widely in the treatment of various infectious diseases in adults as a result of their excellent spectrum of activity, significant tissue penetration and convenient routes of administration. Their use in children, however, has been limited until recently as a result of possible fluoroquinolone-induced joint toxicity. Nevertheless, this group of antibiotics is rapidly gaining consideration for use in children as new agents are emerging with a wide antimicrobial range of action and minimal toxicity, even in young children. This review presents the pharmacokinetics, clinical indications and possible toxicity of fluoroquinolones in children, as well as the newer agents and their safety profile in pediatrics.

Cardiovascular and metabolic safety profiles of the fluoroquinolones

INTRODUCTION

Certain fluoroquinolones share similar indications of use. A comparison among Cardiovascular and metabolic (i.e., dysglycemia) safety profiles of the fluoroquinolones might be particularly useful for the prescribers' decision-making process as well as to hypothesize future researcher purposes.

AREAS COVERED

A literature search was conducted using keywords apt to identify information on safety profile of the fluoroquinolones. Publications concerned with descriptive and etiological surveys were manually reviewed.

EXPERT OPINION

Cardiac alterations and blood glucose impairments might be associated with any fluoroquinolone. However, the benefit/risk profile of these agents could be stratified for the single compounds. Several predisposing factors, such as diabetes, heart illnesses and their related pharmacotherapies, might exacerbate the risk of potentially serious adverse events. In this context, the opportunity of the more appropriate choice among different fluoroquinolones could be applicable.

Levofloxacin can be used effectively as a positive control in thorough QT/QTc studies in healthy volunteers

AIMS

To characterize the effects of levofloxacin on QT interval in healthy subjects and the most appropriate oral positive control treatments for International Conference on Harmonization (ICH) E14 QT/QTc studies.

METHODS

Healthy subjects received a single dose of levofloxacin (1000 or 1500 mg), moxifloxacin (400 mg) or placebo in a four-period crossover design. Digital 12-lead ECGs were recorded in triplicate. Measurement of QT interval was performed automatically with subsequent manual onscreen over-reading using electronic callipers. Blood samples were taken for determination of levofloxacin and moxifloxacin concentrations.

RESULTS

Mean QTcI (QT interval corrected for heart rate using a correction factor that is applicable to each individual) was prolonged in subjects receiving moxifloxacin 400 mg compared with placebo. The largest time-matched difference in QTcI for moxifloxacin compared with placebo was observed to be 13.19 ms (95% confidence interval 11.21, 15.17) at 3.5 h post dose. Prolonged mean QTcI was also observed in subjects receiving levofloxacin 1000 mg and 1500 mg compared with placebo. The largest time-matched difference in QTcI compared with placebo was observed at 3.5 h post dose for both 1000 mg and 1500 mg of levofloxacin [mean (95%) 4.42 ms (2.44, 6.39) in 1000 mg and 7.44 ms (5.47, 9.42) in 1500 mg]. A small increase in heart rate was observed with levofloxacin during the course of the study. However, moxifloxacin showed a greater increase compared with levofloxacin.

CONCLUSIONS

Both levofloxacin and moxifloxacin can fulfil the criteria for a positive comparator. The ICH E14 guidelines recommend a threshold of around 5 ms for a positive QT/QTc study. The largest time-matched difference in QTc for levofloxacin suggests the potential for use in more rigorous QT/QTc studies. This study has demonstrated the utility of levofloxacin on the assay in measuring mean QTc changes around 5 ms.

Safety profile of the fluoroquinolones: focus on levofloxacin

The fluoroquinolone class of antibacterial agents are among the most frequently prescribed drugs, with utility in a broad range of bacterial infections. Although very useful agents, the fluoroquinolones as a class are associated with a number of adverse events, some with considerable clinical significance. In the past 15-20 years, tolerability concerns have led to restrictions on the use of the fluoroquinolones and, in some instances, the withdrawal of agents from the market. This review focuses on the safety and tolerability of levofloxacin, a third-generation fluoroquinolone, relative to other fluoroquinolones. A literature search was performed of the MEDLINE database encompassing the dates 1980-2009, using as keywords the drug names levofloxacin and concurrently marketed fluoroquinolones combined with the words 'safety', 'adverse effect' or 'adverse drug reaction', or the name of the specific adverse effect. Adverse events commonly associated with the fluoroquinolones include gastrointestinal and CNS toxicity (most frequently headache and dizziness), as well as other adverse events including ECG abnormalities (for example QT interval prolongation), disrupted glucose metabolism, phototoxicity, tendon and joint disorders, hypersensitivity and skin disorders, and hepatic toxicity. Package inserts for the fluoroquinolones in Europe and the US contain warnings regarding these risks. US package inserts also carry 'black-box' warnings regarding the risk of tendon rupture and joint disorders with these agents; however, there is a substantial body of evidence to indicate that there are marked differences in the tolerability profiles of the individual agents within the fluoroquinolone class. These differences may be explained, at least in part, by structural differences: all fluoroquinolones share a basic quinolone core, with differences in specific side chains underlying the adverse event relationships. Furthermore, many of the fluoroquinolone-associated adverse effects and toxicities occur more frequently in patients with pre-existing risk factors, or in certain subpopulations. Notably, package inserts for the fluoroquinolones carry warnings regarding use in the elderly, paediatric patients and patients with pre-existing, or factors predisposing to, seizure disorders. Because of this, many adverse reactions with these agents could be prevented by improving patient screening and education. The recent withdrawal of gatifloxacin due to dysglycaemia makes it timely to review the safety and tolerability of the individual agents in this class. Overall, it appears that levofloxacin is relatively well tolerated, with low rates of clinically important adverse events such as CNS toxicity, cardiovascular toxicity and dysglycaemia.

Exposure to antibacterial agents with QT liability in 14 European countries: trends over an 8-year period

AIMS

(i) To classify antibacterial agents with QT liability on the basis of the available evidence, and (ii) to assess trends in their consumption over an 8-year period (1998-2005) in 14 European countries.

METHODS

Current published evidence on QT liability of antibiotics was retrieved through MEDLINE search and joined to official warnings from regulatory agencies. Each drug was classified according to an already proposed algorithm based on the strength of evidence: from group A (any evidence) to group E (clinical reports of torsades de pointes and warnings on QT liability). Consumption data were provided by the European Surveillance of Antibacterial Consumption (ESAC) project and were expressed as defined daily doses per 1000 inhabitants per day (DID).

RESULTS

Among 21 detected compounds, nine [six fluoroquinolones (FQs) and three macrolides (MACs)] belonged to group E. Use of group E drugs ranged from 1.3 (Sweden) to 4.1 DID (Italy) in 1998 and from 1.2 (Sweden) to 6.5 DID (Italy) in 2005. Significant exposure was observed in Italy and Spain (6.5 and 3.8 DID, respectively, in 2005). Only Denmark, Sweden and UK showed a slight decrease in use. Exposure to clarithromycin increased in 10 out of 14 countries, with a marked increment in Italy (3 DID in 2005).

CONCLUSIONS

Notwithstanding regulatory measures, in 2005 there was still significant exposure to antibacterials with strong evidence of QT liability and, in most countries, it was even increased. This warrants further investigation of appropriateness of use and suggests closer monitoring of group E drugs. Physicians should be aware when prescribing them to susceptible patients.

Ciprofloxacin-induced Q-T interval prolongation

PURPOSE

A case of Q-T interval prolongation in a pediatric patient with no known risk factors for the development of a long Q-T syndrome is reported.

SUMMARY

A 16-year-old boy arrived at a children's hospital reporting mucous diarrhea that had lasted two weeks, light-headedness with two blackouts on the day before his arrival to the hospital, and a 4.3-kg weight loss over the previous three weeks. He had a 3.5-year history of Crohn's disease and had been hospitalized for two months with a diagnosis of colitis with cryptitis. He was admitted for the treatment of an acute flare of Crohn's disease and a perirectal abscess. The patient was started on i.v. ciprofloxacin 400 mg twice daily and metronidazole 500 mg every six hours. The selected agents provided adequate empirical coverage of the suspected organisms and would not be contraindicated with the patient's allergy to penicillin. Within 48 hours of administration of ciprofloxacin, the patient became bradycardic. The cardiology service was consulted, and an electrocardiogram showed a mildly prolonged Q-T interval (corrected Q-T interval, 486 msec) and low heart rate (42 beats/min). Antimicrobial therapy was changed to ampicillin and then to linezolid. The patient's Q-T interval normalized within seven days of ciprofloxacin discontinuation. The patient had no further cardiac anomalies. Two weeks later, he was discharged on linezolid and aztreonam for the treatment of his abscess and was responding to treatment.

CONCLUSION

A pediatric patient with Crohn's disease and colitis with cryptitis developed a prolonged Q-T interval within 48 hours of treatment with ciprofloxacin.

Arrhythmias associated with fluoroquinolone therapy

Fluoroquinolones are widely used and well tolerated antibacterial agents. However, prolongation of the QT interval is an adverse effect associated with the use of fluoroquinolones. According to the available case reports and clinical studies, moxifloxacin carries the greatest risk of QT prolongation from all available quinolones in clinical practice and it should be used with caution in patients with predisposing factors for Torsades de pointes (Tdp). Although gemifloxacin, levofloxacin and ofloxacin are associated with a lower risk of QT prolongation compared with moxifloxacin, they should also be used with caution in patients with risk factors for QT prolongation. Ciprofloxacin appears to be associated with the lowest risk for QT prolongation and the lowest rate of Tdp. The overall risk of Tdp is small with the use of fluoroquinolones. Clinicians can minimise that risk by avoiding prescriptions of multiple medications associated with QT interval prolongation, especially in high-risk patients.

Hospital Pharmacy Pulse - Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this new feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope of topics.