Profile of moxifloxacin drug interactions

Revisiting Oral Fluoroquinolone and Multivalent Cation Drug-Drug Interactions: Are They Still Relevant?

Fluoroquinolones are a widely-prescribed, broad-spectrum class of antibiotics with several oral formulations notable for their high bioavailability. For certain infections, fluoroquinolones are the first line or only treatment choice. When administered orally, fluoroquinolones require proper administration to ensure adequate systemic absorption and, thereby, protect patients from treatment failure. Oral drug preparations that contain multivalent cations are well known to chelate with fluoroquinolones in the gastrointestinal tract; co-administration may lead to clinically significant decreases in oral fluoroquinolone bioavailability and an overall increase in fluoroquinolone-resistant bacteria. Based on a search and evaluation of the literature, this focused review describes oral fluoroquinolone-multivalent cation drug-drug interactions and their magnitude and offers several clinical management strategies for these potentially clinically significant interactions.

Lithium Intoxication: A Possible Interaction with Moxifloxacin

Lithium is a well-known treatment for patients with mood disorders. Intoxication by lithium may be lethal particularly in elderly due to altered pharmacokinetics, renal impairment or multiple drug use. We presented a 74-year-old female patient who had been stabile with lithium carbonate 600 mg/day for 5 years and developed lithium intoxication after bronchiolitis. She presented with altered mental status. The neurological signs resolved slowly after lithium and moxifloxacin were stopped immediately and fluid resuscitation administered. Considering possible drug interactions on elderly patients receiving lithium is essential.

Evaluation of the Potential for Drug Interactions With Patiromer in Healthy Volunteers

INTRODUCTION

Patiromer is a potassium-binding polymer that is not systemically absorbed; however, it may bind coadministered oral drugs in the gastrointestinal tract, potentially reducing their absorption.

METHODS

Twelve randomized, open-label, 3-period, 3-sequence crossover studies were conducted in healthy volunteers to evaluate the effect of patiromer (perpetrator drug) on absorption and single-dose pharmacokinetics (PK) of drugs (victims) that might be commonly used with patiromer. Subjects received victim drug alone, victim drug administered together with patiromer 25.2 g (highest approved dose), and victim drug administered 3 hours before patiromer 25.2 g. The primary PK endpoints were area under the curve (AUC), extrapolated to infinity (AUC0-∞), and maximum concentration ( Cmax). Results were reported as 90% confidence intervals (CIs) about the geometric mean AUC0-∞ and Cmax ratios with prespecified equivalence limits of 80% to 125%.

RESULTS

Overall, 370 subjects were enrolled, with 365 receiving ≥1 dose of patiromer; 351 subjects completed the studies and all required treatments. When coadministered with patiromer, the 90% CIs for AUC0-∞ remained within 80% to 125% for 9 drugs (amlodipine, cinacalcet, clopidogrel, furosemide, lithium, metoprolol, trimethoprim, verapamil, and warfarin). The AUC0-∞ point estimate ratios for levothyroxine and metformin with patiromer coadministration were ≥80%, with the lower bounds of the 90% CIs at 76.8% and 72.8%, respectively. For ciprofloxacin, the point estimate for AUC0-∞ was 71.5% (90% CI: 65.3-78.4). For 8 of 12 drugs, point estimates for Cmax were ≥80% with patiromer coadministration; for ciprofloxacin, clopidogrel, metformin, and metoprolol, the point estimates were <80%. When patiromer was administered 3 hours after each victim drug, the 90% CIs for AUC0-∞ and Cmax for each drug were within the prespecified 80% to 125% limits.

CONCLUSION

For 9 of the 12 drugs coadministered with patiromer, there were no clinically significant drug-drug interactions. For 3 drugs (ciprofloxacin, levothyroxine, and metformin), a 3-hour separation between patiromer and their administration resulted in no clinically significant drug-drug interactions.

Moxifloxacin-Induced Seizures in an Epileptic Patient

Objective:

To report a patient with seizures probably related to the use of moxifloxacin, a fourth-generation quinolone.

Case Summary:

A 79-year-old white man developed status epilepticus after a 4-day course of moxifloxacin for respiratory infection. He had experienced seizures 2 years before presentation. The patient was currently receiving warfarin, theophylline 400 mg/d, albuterol; furosemide, potassium, and digoxin; and omeprazole for chronic obstructive pulmonary disease, atrial fibrillation with mild heart failure, and heartburn, respectively. He also had moderate renal failure. Despite aggressive therapy, the patient developed progressive respiratory insufficiency and died.

Discussion:

Quinolone use is associated with a variety of central nervous system (CNS) adverse effects in approximately 1–2% of patients. In fact, CNS adverse effects represent the second most frequently encountered form of quinolone toxicity after gastrointestinal involvement. Occasionally, quinolones induce seizures, but, as of October 17, 2003, none have been reported in the literature. Use of the Naranjo probability scale indicated a probable relationship between seizures and moxifloxacin administration in this patient. Seizures may be mediated by CNS stimulation secondary to quinolone binding to γ-aminobutyric acid receptors. Coexisting medical conditions and concurrent medications also facilitate seizure appearance. Risk factors include seizure history, hypokalemia, alkalosis, renal failure, and concomitant treatment with agents that lower the seizure threshold. These factors were not present in this patient except for a prior history of seizures and mild renal failure.

Conclusions:

Seizures with quinolones, albeit rare, need to be considered in certain populations, particularly patients who have had prior seizures, the elderly, patients with renal dysfunction, and patients on multiple medications.

Electrochemically driven drug metabolism via a CYP1A2-UGT1A10 bienzyme confined in a graphene nano-cage

A graphene nano-cage with regulatable space for the assembly of a cytochrome P450 1A2-UDP-glucuronosyltransferase 1A10 bienzyme complex has been constructed via a click reaction, and successfully used to study drug sequential metabolism using an electrochemically-driven method.

Thorough QT study of the effect of oral moxifloxacin on QTc interval in the fed and fasted state in healthy Japanese and Caucasian subjects

AIMS

The aims of this study were three-fold and were to (i) investigate the effect of food (fasted and fed state) on the degree of QT prolongation caused by moxifloxacin under the rigorous conditions of a TQT study, (ii) differentiate the effects on QTc that arise from changes in PK from those arising as a result of electrophysiological changes attributable to raised levels of C-peptide [11] offsetting in part the IKr blocking properties of moxifloxacin and (iii) characterize the QTc F profile of oral moxifloxacin (400 mg) in healthy Japanese volunteers compared with Caucasian subjects.

METHODS

The study population consisted of 32 healthy non-smoking, Caucasian (n = 13) and Japanese (n = 19), male and female subjects, aged between 20-45 years with a body mass index of between 18 to 25 kg m(-2). Female volunteers were required to use an effective contraceptive method or be abstinent. Subjects with ECGs which were deemed unsuitable for evaluation in a TQT study were excluded. ECGs were recorded in triplicate with subsequent blinded manual adjudication of the automated interval measurements. Electrocardiograms in the placebo arm were recorded twice in fasted and fed condition.

RESULTS

The results demonstrated a substantial change in the typical moxifloxacin effect on the ECG. The effect on ΔΔQTc in the fed state led to a significant delay and a modest reduction compared with the fasted state correcting both conditions with the corresponding placebo data. The largest QTc F change from baseline in the fed state was observed at 4 h with a peak value of 11.6 ms (two-sided 90% CI 9.1, 14.1). In comparison, the largest QTc F change observed in the fasted state was 14.4 ms (90% CI 11.9, 16.8) and occurred at 2.5 h post-dose. The PK of moxifloxacin were altered by food and this change was consistent with the observed QTc F change. In the fed state plasma concentrations of moxifloxacin were considerably and consistently lower in comparison with the fasted state, and this applied to both ethnicities. The concentration-effect analysis revealed that there was no change in slope and confirmed that the difference in this analysis was caused by a change in the PK profile of moxifloxacin. Comparisons of the moxifloxacin effect in the fed state compared with fasted placebo also revealed a pharmacodynamic effect whereby a meal appears to antagonize the effects of moxifloxacin on the lengths of the QTc interval.

CONCLUSIONS

Our findings demonstrate that the food effect by itself leads to a shortening of the QTc interval offsetting in part the effects of a 400 mg single dose of oral moxifloxacin. The typical moxifloxacin PK profile is also altered by food prior to dosing reducing the Cmax and delays the peak effects on QTc up to several hours thereby reducing the overall magnitude of the effect and delaying the peak QTc prolongation. The contribution of the two effects was clearly discernible. Given that moxifloxacin is sometimes given with food in TQT studies, consideration should be given to adequate baseline corrections and appropriate sampling time points. In this study the PK-PD relationship was similar for Japanese and Caucasian subjects in the fed and fasted conditions, thereby providing further evidence that the sensitivity to the QTc prolonging effects of fluoroquinolones was likely to be independent of ethnicity. The small differences observed between the two subpopulations were not statistically significant. However, future studies should give consideration to formal ethnic comparisons as a secondary outcome parameter as very little is known about the relationship between ethnicity and drug effects on cardiac repolarization.

Gender analysis of moxifloxacin clinical trials

PURPOSE

To determine the inclusion of women and the sex-stratification of results in moxifloxacin Clinical Trials (CTs), and to establish whether these CTs considered issues that specifically affect women, such as pregnancy and use of hormonal therapies. Previous publications about women's inclusion in CTs have not specifically studied therapeutic drugs. Although this type of drug is taken by men and women at a similar rate, adverse effects occur more frequently in the latter.

METHODS

We reviewed 158 published moxifloxacin trials on humans, retrieved from MedLine and the Cochrane Library (1998-2010), to determine whether they complied with the gender recommendations published by U.S. Food and Drug Administration Guideline.

RESULTS

Of a total of 80,417 subjects included in the moxifloxacin CTs, only 33.7% were women in phase I, in contrast to phase II, where women accounted for 45%, phase III, where they represented 38.3% and phase IV, where 51.3% were women. About 40.9% (n=52) of trials were stratified by sex and 15.3% (n=13) and 9% (n=7) provided data by sex on efficacy and adverse effects, respectively. We found little information about the influence of issues that specifically affect women. Only 3 of the 59 journals that published the moxifloxacin CTs stated that authors should stratify their results by sex.

CONCLUSIONS

Women are under-represented in the published moxifloxacin trials, and this trend is more marked in phase I, as they comprise a higher proportion in the other phases. Data by sex on efficacy and adverse effects are scarce in moxifloxacin trials. These facts, together with the lack of data on women-specific issues, suggest that the therapeutic drug moxifloxacin is only a partially evidence-based medicine.

Sequential intravenous/oral moxifloxacin monotherapy for complicated skin and skin structure infections: a meta-analysis of randomised controlled trials

OBJECTIVES

The presumed superiority of moxifloxacin for the treatment of complicated skin and skin structure infections (cSSSIs) is based on laboratory data, but has not yet been established on clinical grounds. The aim of this meta-analysis was to evaluate the efficacy and safety of sequential intravenous (i.v.)/oral (p.o.) moxifloxacin monotherapy for the treatment of cSSSIs.

METHODS

Randomised controlled trials (RCTs) published prior to November 2012 were systematically retrieved from PubMed, MEDLINE, EMBASE, ScienceDirect, ClinicalTrials.gov and the Cochrane Central Register of Controlled Trials. Finally, a meta-analysis of all RCTs eligible for inclusion criteria was performed.

RESULTS

Three studies that enrolled 2255 patients were included in the meta-analysis. There were no statistically significant differences between patients given moxifloxacin and those given other antibiotics with regard to clinical success rate [1667 patients, odds ratio (OR) = 0.83, 95% confidence interval (CI) 0.63 to 1.09, p = 0.18], bacteriological success rate (bacteriological success rates: 1502 patients, OR = 0.90, 95% CI 0.68-1.18, p = 0.45) or mortality (2207 patients, OR = 1.96, 95% CI 0.79-4.88, p = 0.15). Significantly, more overall adverse events (AEs) were associated with the use of moxifloxacin than with other antibiotics (2207 patients, OR = 1.21, 95%CI 1.00-1.45, p = 0.04). However, there was no statistically significant difference in the occurrence of drug-related AEs, serious AEs or serious drug-related AEs between patients given moxifloxacin and those given other antibiotics.

CONCLUSION

Sequential i.v./p.o. moxifloxacin monotherapy is an effective and relatively safe option for the treatment of cSSSIs. Other benefits of moxifloxacin may make it a more viable option compared with the currently used regimens.

Clinical pharmacology and lesion penetrating properties of second- and third-line antituberculous agents used in the management of multidrug-resistant (MDR) and extensively-drug resistant (XDR) tuberculosis

Failure of first-line chemotherapy to cure tuberculosis (TB) patients occurs, in part, because of the development of resistance to isoniazid (INH) and rifampicin (RIF) the two most sterilizing agents in the four-drug regimen used to treat primary infections. Strains resistant to both INH and RIF are termed multidrug-resistant (MDR). Treatment options for MDR patients involve a complex array of twenty different drugs only two classes of which are considered to be highly effective (fluoroquinolones and aminoglycosides). Resistance to these two classes results in strains known as extensively drug-resistant (XDR) and these types of infections are becoming increasingly common. Many of the remaining agents have poorly defined pharmacology but nonetheless are widely used in the treatment of this disease. Several of these agents are known to have highly variable exposures in healthy volunteers and little is known in the patients in which they must be used. Therapeutic drug monitoring (TDM) is infrequently used in the management of MDR or XDR disease yet the clinical pharmacokinetic studies that have been done suggest this might have a large impact on disease outcome. We review what is known about the pharmacologic properties of each of the major classes of second- and third-line antituberculosis agents and suggest where judicious use of TDM would have the maximum possible impact. We summarize the state of knowledge of drug-drug interactions (DDI) in these classes of agents and those that are currently in clinical trials. Finally we consider what little is known about the ability of TB drugs to reach their ultimate site of action--the interior of a granuloma by penetrating the diseased lung area. Careful consideration of the pharmacology of these agents is essential if we are to avoid further fueling the growing epidemic of highly drug-resistant TB and critical in the development of new antituberculosis drugs.

Determination of the inhibitory potential of 6 fluoroquinolones on CYP1A2 and CYP2C9 in human liver microsomes

AIM

To determine the inhibitory potential of 2 new fluoroquinolones, caderofloxacin and antofloxacin, together with 4 marketed fluoroquinolones, moxifloxacin, gatifloxacin, levofloxacin, and ciprofloxacin, on the activity of cytochrome P450 isoforms 1A2 (CYP1A2) and 2C9 (CYP2C9).

METHODS

Probe substrates, phenacetin (CYP1A2), and tolbutamide (CYP2C9) were incubated with human liver microsomes and the metabolites were analyzed by liquid chromatography/mass spectrometry using electrospray ionization in positive or negative mode. Glipizide was used as the internal standard in both modes. The inhibitory potential of fluoroquinolones on CYP1A2 and CYP2C9 was investigated.

RESULTS

The IC50 values (micromol/L) determined with the cocktail were in agreement with individual probe substrates (alpha-naphthoflavone: 0.27 vs 0.26; sulfaphenazole: 0.49 vs 0.37). Ciprofloxacin showed weak inhibition on both the activity of CYP1A2 (IC50 135 micromol/L) and CYP2C9 (IC50 180 micromol/L), whereas levofloxacin inhibited only CYP2C9 (IC50 210 micromol/L). Caderofloxacin, antofloxacin, moxifloxacin, and gatifloxacin showed little or no inhibition on the activity of CYP1A2 or CYP2C9 when tested at comparable concentrations (0-200 mg/L).

CONCLUSION

Caderofloxacin, antofloxacin, moxifloxacin, and gatifloxacin are negligible inhibitors to CYP1A2 and CYP2C9. The in vitro system can be used as a high-throughput model to screen similar compounds for the early identification of drug-drug interaction potential.

Moxifloxacin: a respiratory fluoroquinolone

BACKGROUND

Respiratory quinolones are a class of antimicrobials with a high activity against most respiratory pathogens. Moxifloxacin is a fourth-generation fluoroquinolone that has been shown to be effective against Gram-positive, Gram-negative, and atypical strains, as well as multi-drug resistant Streptococcus pneumoniae.

OBJECTIVE

To review and update the clinical efficacy of moxifloxacin in the treatment of respiratory infections.

METHOD

To perform a systematic review of publications on the clinical efficacy of moxifloxacin in respiratory infections.

RESULTS

The clinical efficacy of moxifloxacin has been shown in controlled studies of community-acquired pneumonia, exacerbations of chronic bronchitis and acute bacterial rhinosinusitis. Moxifloxacin has demonstrated a faster resolution of symptoms in community-acquired pneumonia and exacerbations of chronic bronchitis patients compared with first-line therapy together with excellent eradication rates.

CONCLUSIONS

The use of moxifloxacin as first-line therapy for moderate to severe respiratory infections in the community and the hospital has been recognized in international guidelines.

Involvement of Mrp2 (Abcc2) in biliary excretion of moxifloxacin and its metabolites in the isolated perfused rat liver

Moxifloxacin is a novel antibacterial agent that undergoes extensive metabolism in the liver to the glucuronide M1 and the sulfate M2, which are eliminated via the bile. To investigate the role of the multidrug resistance-associated protein (Mrp2) as the hepatic transport system for moxifloxacin and its conjugates, livers of Wistar and Mrp2-deficient TR- rats were perfused with moxifloxacin (10 microM) in a single-pass system. Values for the hepatic extraction ratio (E) and clearance (Cl) were insignificantly higher in TR- rats than Wistar rats (0.193+/-0.050 vs 0.245+/-0.050 for E; 6.85+/-1.96 vs 8.73+/-1.82 mL min(-1) for Cl), whereas biliary excretion and efflux into perfusate over 60 min were significantly lower in the mutant rat strain. Cumulative biliary excretion of M1, M2 and moxifloxacin was significantly reduced to 0.027%, 19.1%, and 29.6% in the TR- rats compared with Wistar rats, indicating that the biliary elimination of M1 is mediated exclusively by Mrp2, whereas that of M2 and moxifloxacin seems to depend mostly on Mrp2 and, to a smaller extent, a further unidentified canalicular transporter. Moxifloxacin stimulates bile flow by up to 11% in Wistar rats, but not in TR- rats, further supporting an efficient transport of this drug and its glucuronidated and sulfated metabolites by Mrp2. Moxifloxacin (10 microM) also reversibly inhibited the Mrp2-mediated biliary elimination of bromsulphthalein in Wistar rats by 34%, indicating competition with the elimination of Mrp2-specific substrates. In conclusion, we found that Mrp2 mediates the biliary elimination of moxifloxacin and its glucuronidated and sulfated metabolites in rats. MRP2 may therefore play a key role in the transport of moxifloxacin and its conjugates into bile in humans.

Antimicrobial safety: focus on fluoroquinolones

BACKGROUND/PURPOSE

Infrequent toxicities associated with certain drugs and drug classes have recently gained much attention from different health-care perspectives. To protect the patient, continued surveillance of safety and tolerability data is essential. Data from preclinical testing, phase 1-3 trials, and postmarketing surveillance may be used to objectively assess the risks associated with a specific drug or family of compounds. This review summarizes safety and tolerability data for the quinolones.

MAIN FINDINGS

The most common adverse events associated with the quinolone class involve the gastrointestinal tract (nausea and diarrhea) and central nervous system (CNS) (headache and dizziness). These adverse events are usually mild and do not require discontinuation of therapy. Uncommon and potentially serious quinolone-related adverse events involve the cardiovascular system (rate-corrected electrocardiographic QT interval prolongation), musculoskeletal system (tendinitis and tendon rupture), endocrine system (glucose homeostasis dysregulation), renal system (crystalluria, interstitial nephritis, and acute renal failure), and the CNS (seizures). Severe idiosyncratic adverse events are specific to individual agents that may share some structural congruity, such as the 1-(2,4)-difluorophenyl group shared by trovafloxacin (associated with hepatitis), temafloxacin (associated with hemolytic-uremic syndrome), and tosufloxacin (associated with eosinophilic pneumonitis). Overall, discontinuation rates from clinical trials were <4% for the currently marketed quinolones. Quinolones with higher discontinuation rates, such as trovafloxacin (7.0%) and grepafloxacin (6.4%), are no longer available for general use.

CONCLUSIONS

The currently marketed quinolones are well tolerated, with safety profiles similar to those of other antimicrobial classes. Although adverse effects are unusual, some, including tendinitis and CNS-related effects, are more common with quinolones than with other antimicrobial classes. Rare adverse effects attributed to some members of the quinolone family (e.g., Torsades de Pointes, hepatotoxicity, and dysglycemias) are more likely to occur in select "susceptible" populations. These adverse events can often be circumvented by avoiding exposure to the specific quinolone. In some cases, the therapeutic value offered by a quinolone may outweigh its potential risks.

Drug interactions during therapy with three major groups of antimicrobial agents

This review focuses on drug-drug interactions with three major groups of antimicrobial agents: macrolides (including azalides and ketolides), quinolones, which are widely used for the treatment of bacterial infections, and azoles, which are used for antifungal therapy. Macrolides and the ketolide telithromycin are potent inhibitors of CYP3A4 and thus interfere with the pharmacokinetics of many other drugs that are metabolised by this enzyme. In contrast, although closely related, azithromycin is not a cytochrome inhibitor. All quinolones form complexes with di- and trivalent cations and, therefore, the absorption of quinolones can be dramatically reduced when given concomitantly with mineral antacids, zinc or iron preparations. Ciprofloxacin exhibits an inhibitory potential for the cytochrome isoenzyme 1A2, resulting in an inhibition of theophylline metabolism. Other quinolones, such as levofloxacin or moxifloxacin, do not interfere with theophylline metabolism. The systemic azoles, such as ketoconazole, itraconazole, fluconazole and voriconazole, are inhibitors of CYP isoenzymes, such as CYP3A4, CYP2C9 and CYP2C19, to varying degrees. In addition, some are substrates of the MDR-1 gene product, P-glycoprotein. These features are the basis for most of the interactions occurring during azole therapy (e.g., in severely ill patients in the hospital who are treated with multiple drugs).

QT prolongation and proarrhythmia by moxifloxacin: concordance of preclinical models in relation to clinical outcome

Moxifloxacin, a fluoroquinolone antibiotic associated with QT prolongation, has been recommended as a positive control by regulatory authorities to evaluate the sensitivity of both clinical and preclinical studies to detect small but significant increases in QT interval measurements. In this study, we investigated effects of moxifloxacin on the hERG current in HEK-293 cells, electrocardiograms in conscious telemetered dogs, and repolarization parameters and arrhythmogenic potentials in the arterially perfused rabbit ventricular wedge model. Moxifloxacin inhibited the hERG current with an IC50 of 35.7 microM. In conscious telemetered dogs, moxifloxacin significantly prolonged QTc at 30 and 90 mg kg(-1), with mean serum Cmax of 8.52 and 22.3 microg ml(-1), respectively. In the wedge preparation, moxifloxacin produced a concentration-dependent prolongation of the action potential duration, QT interval, and the time between peak and end of the T wave, an indicator for transmural dispersion of repolarization. Phase 2 early after-depolarizations were observed in one of five experiments at 30 microM and five of five experiments at 100 microM. The arrhythmogenic potential was also concentration-dependent, and 100 microM ( approximately 18-fold above the typical unbound Cmax exposure in clinical usage) appeared to have a high risk of inducing torsade de pointes (TdP). Our data indicated a good correlation among the concentration-response relationships in the three preclinical models and with the available clinical data. The lack of TdP report by moxifloxacin in patients without other risk factors might be attributable to its well-behaved pharmacokinetic profile and other dose-limiting effects.

Sequential intravenous/oral moxifloxacin versus intravenous piperacillin-tazobactam followed by oral amoxicillin-clavulanate for the treatment of complicated skin and skin structure infection

In this prospective, double-blind, multicentre trial, adult patients with complicated skin and skin structure infection (cSSSI) randomly received sequential intravenous (i.v.)/oral (p.o.) moxifloxacin (400 mg once a day) or a control regimen of i.v. piperacillin-tazobactam (3.0/0.375 g every 6 h) followed by p.o. amoxicillin-clavulanate (800 mg every 12 h), each for 7-14 days. Clinical cure rates at the test-of-cure visit (10-42 days post therapy) for the efficacy-valid population were 79% (143/180) for the moxifloxacin-treated group and 82% (153/187) for the control group (95% confidence interval, -12.04, 3.29). Bacteriological eradication rates for Staphylococcus aureus, the most prevalent organism, were 78% and 80%, respectively. The incidence of drug-related adverse events was similar for both groups (31% moxifloxacin, 30% control). Sequential i.v./p.o. moxifloxacin was as effective and well tolerated as i.v. piperacillin-tazobactam followed by p.o. amoxicillin-clavulanate in treating patients with cSSSI.

Retrospective analysis of the safety profile of oral moxifloxacin in elderly patients enrolled in clinical trials

BACKGROUND AND OBJECTIVE

As aging is associated with physiological changes, including renal and hepatic insufficiency, and a higher risk of drug interactions, special attention needs to be directed towards the safety of medications in the elderly. The objective of this analysis was to evaluate the safety of oral moxifloxacin in elderly patients who were enrolled in clinical trials and to compare these results to those of other commonly used antibacterials.

METHODS

Safety data from 27 prospective, randomised, comparative phase II/III trials of oral moxifloxacin included in the Bayer clinical trial database were pooled and analysed by age group (<65 years of age, 65-74 years of age, > or = 75 years of age) and by treatment group (moxifloxacin vs comparator). The primary endpoints included rates of treatment-emergent adverse events (all adverse events regardless of causality), drug-related adverse events, drug-related serious adverse events, deaths and premature discontinuations because of a treatment-emergent adverse event. A treatment by age group interaction test was used to determine if the comparison between moxifloxacin and the comparator group in the incidence rates of any treatment-emergent or drug-related adverse events were affected by increasing age.

RESULTS

Of the 12 231 patients who had valid safety data, 6270 had been treated with oral moxifloxacin and 5961 with a comparator antibacterial. The most frequently used comparators were cefuroxime and clarithromycin. Most patients (n = 9671) were <65 years of age (4939 moxifloxacin, 4732 comparator); 1636 patients were 65-74 years of age (842 moxifloxacin, 794 comparator); and 924 patients were > or = 75 years of age (489 moxifloxacin, 435 comparator). The treatment by age group interaction test revealed that the comparison of drug-related adverse event rates between the moxifloxacin and comparator group were not affected by increasing age (p = 0.43). Rates of premature termination between the moxifloxacin and comparator treatment groups also did not increase with age (p = 0.552). No arrhythmias related to corrected QT (QTc) interval prolongation were reported following oral moxifloxacin or comparator treatment in this large group of young and elderly patients. Overall, the number of deaths was similar between the treatment groups (17 moxifloxacin, 19 comparator).

CONCLUSIONS

Drug-related adverse event rates associated with oral moxifloxacin or the comparator therapy used in these studies did not significantly increase with advancing age. This pooled analysis suggests that oral moxifloxacin can be safely used in elderly patients with characteristics consistent with those enrolled into the clinical trials.

Moxifloxacin: a review of its use in the management of bacterial infections

Moxifloxacin (Avelox) is a fluoroquinolone antibacterial with a methoxy group in the C-8 position and a bulky C-7 side chain. Moxifloxacin is approved for use in the treatment of acute exacerbations of chronic bronchitis (AECB), community-acquired pneumonia (CAP), acute bacterial sinusitis and uncomplicated skin and skin structure infections (approved indications may differ between countries). Moxifloxacin has a broad spectrum of antibacterial activity, including activity against penicillin-resistant Streptococcus pneumoniae. It achieves good tissue penetration and has a convenient once-daily administration schedule, as well as being available in both intravenous and oral formulations in some markets. Moxifloxacin has good efficacy in the treatment of patients with AECB, CAP, acute bacterial sinusitis and uncomplicated skin and skin structure infections, and is generally well tolerated. Thus, moxifloxacin is an important option in the treatment of bacterial infections.

Safety profile of oral and intravenous moxifloxacin: Cumulative data from clinical trials and postmarketing studies

BACKGROUND

The established safety profile of the fluoroquinolones has been disrupted in the past decade by the detection of low-frequency but potentially serious adverse events that have led to the license suspension, voluntary withdrawal, or restricted use of specific members of the class. Moxifloxacin is a broad-spectrum, advanced-generation fluoroquinolone that has potent activity against respiratory tract infections in adults in both oral and IV formulations.

OBJECTIVE

The goal of this article was to provide an overview of the cumulative safety data on both oral and IV moxifloxacin, including data from the most recent clinical trials and postmarketing studies.

METHODS

Data from clinical trials of moxifloxacin were captured from an electronic database maintained by the manufacturer. Safety data for oral moxifloxacin were obtained from 30 Phase II/III comparator studies (n = 7,368 moxifloxacin, n = 5,687 comparators), 1 Phase IV study (n = 18,374), and 4 postmarketing observational studies (n = 27,756). Safety data for IV moxifloxacin were obtained from 2 Phase III comparator studies (n = 550 maxifloxacin, n = 579 comparators). In addition, pharmacokinetic data were reviewed.

RESULTS

In Phase II/III comparator studies, gastrointestinal complaints were the most common adverse drug reactions (ADRs) associated with both formulations of moxifloxacin, with nausea occurring in 7.1% and 3.1% of patients receiving oral and IV moxifloxacin, respectively, and diarrhea occurring in 5.2% and 6.2% of patients. Discontinuation rates due to ADRs with oral and IV moxifloxacin were 2.7% and 6.0%, and mortality rates were 0.3% and 4.0%. Similar rates of withdrawal and mortality were observed in the comparator groups. There was no evidence that moxifloxacin caused disturbances in glucose metabolism in patients with or without diabetes mellitus, and there was no evidence of an increased risk for cardiovascular adverse events. Pharmacokinetic analyses indicated that dose adjustment of moxifloxacin does not appear to be necessary in elderly patients, those with renal dysfunction, or those with mild to moderate hepatic impairment. The pharmacokinetics of moxifloxacin have not been studied in patients with severe hepatic insufficiency. Moxifloxacin does not interact with a number of commonly prescribed drugs, although its absorption is decreased by concomitant administration of iron and cationic antacids.

CONCLUSIONS

Based on evidence from >7000 patients in clinical trials and >46,000 patients in postmarketing studies, moxifloxacin is generally well tolerated. Its lack of significant drug interactions in target groups makes it an option in diabetic patients or the elderly, as well as in those with renal impairment.