Peripheral neuropathy associated with fluoroquinolones

One case report of epilepsy and rapidly progressive cognitive impairment after levofloxacin treatment

OBJECTIVE

To report a case of seizure and rapidly progressive cognitive impairment 20 min after intravenous administration of levofloxacin. A 56-year-old woman was admitted to hospital with episodic unconsciousness and unresponsiveness. About 4 days ago, she experienced a loss of consciousness, fell to the floor, and yelled for 2 min, 20 min before the first intravenous dose of levofloxacin. The patient developed symptoms of cognitive impairment after the seizure. Levofloxacin is a synthetic third generation fluoroquinolone used to treat various infectious diseases. Upon admission, the patient was conscious and unresponsive. After 11 days of symptomatic and supportive treatment, the patient was discharged from the hospital with cognition restored to baseline level and no recurrence of seizures 10 months after discharge.

DISCUSSION

Epilepsy is a rare adverse reaction to levofloxacin treatment. The patient in this case had infection-related signs before the onset of the disease, and the disease progressed rapidly with fluctuating changes. After ruling out degenerative, infectious, toxic, and autoimmune causes, the patient's symptoms may be attributed to levofloxacin, and this is the first case of seizure and rapidly progressive cognitive impairment after levofloxacin injection reported in the literature. Clinicians should be aware that unexplained, rapidly progressing cognitive impairment with infection-related signs before onset may be a rare side effect of antibiotics.

Toxic neuropathies: a practical approach

Toxic neuropathies result from exogenous substances damaging the peripheral nerves. There are numerous causes, including prescribed and recreational drugs, heavy metals, industrial agents and biological toxins. Timely recognition of these neuropathies gives better outcomes, as they usually improve or stabilise once the toxin is removed. Most toxic neuropathies are axonal, length-dependent and sensory predominant, although some have significant motor involvement or can present acutely or subacutely. Here, we outline our clinical approach and discuss the major causes of toxic neuropathy, while emphasising the clinical and neurophysiological features and the neuropathy phenotype. We also include an update on newer medications that can cause neuropathy, including immune checkpoint inhibitors and BRAF/MEK inhibitors.

Overview of Side-Effects of Antibacterial Fluoroquinolones: New Drugs versus Old Drugs, a Step Forward in the Safety Profile?

Antibacterial fluoroquinolones (FQs) are frequently used in treating infections. However, the value of FQs is debatable due to their association with severe adverse effects (AEs). The Food and Drug Administration (FDA) issued safety warnings concerning their side-effects in 2008, followed by the European Medicine Agency (EMA) and regulatory authorities from other countries. Severe AEs associated with some FQs have been reported, leading to their withdrawal from the market. New systemic FQs have been recently approved. The FDA and EMA approved delafloxacin. Additionally, lascufloxacin, levonadifloxacin, nemonoxacin, sitafloxacin, and zabofloxacin were approved in their origin countries. The relevant AEs of FQs and their mechanisms of occurrence have been approached. New systemic FQs present potent antibacterial activity against many resistant bacteria (including resistance to FQs). Generally, in clinical studies, the new FQs were well-tolerated with mild or moderate AEs. All the new FQs approved in the origin countries require more clinical studies to meet FDA or EMA requirements. Post-marketing surveillance will confirm or infirm the known safety profile of these new antibacterial drugs. The main AEs of the FQs class were addressed, highlighting the existing data for the recently approved ones. In addition, the general management of AEs when they occur and the rational use and caution of modern FQs were outlined.

Frequency and Management of Adverse Drug Reactions Among Drug-Resistant Tuberculosis Patients: Analysis From a Prospective Study

Drug-resistant tuberculosis (DR-TB) management is often linked with a higher rate of adverse drug reactions (ADRs) needing effective and timely management of these ADRs, which, if left untreated, may result in a higher rate of loss to follow-up of drug-resistant patients.

Study objective: The study was aimed at prospectively identifying the nature, frequency, suspected drugs, and management approaches for ADRs along with risk factors of ADRs occurrence among DR-TB patients at Nishtar Medical University, Hospital, Multan, Pakistan.

Materials and Methods: The prospective study included all the DR-TB patients enrolled for treatment from January 2016 to May 2017 at the study site. Patients were evaluated for the treatment-induced ADRs as per standard criteria of the National Tuberculosis Program, Pakistan. Multivariate logistic regression was used to assess the independent variables associated with the occurrence of ADRs.

Results: Out of 271 DR-TB patients included in the final analysis, it was observed that 55 patients (20.3%) experienced at least three ADRs. A total of 50 (18.5%) patients experienced zero adverse effects, while 15 (5.5%), 33 (12.2%), and 53 (19.6%) patients experienced one, two, and four ADRs, respectively. Gastrointestinal disturbances (66.7%), nervous system disorders (59.4%), and electrolyte disturbances (55.7%) remained the highest reported ADRs during therapy, followed by arthralgia (49.1%), ototoxicity (24%), pruritic reactions/rash (12.9%), dyspnoea (12.5%), and tinnitus (8.8%). Pulmonary cavitation at the baseline visit (p-value 0.001, OR 3.419; 95% CI (1.694–6.902) was significantly associated with the occurrence of ADRs among DR-TB patients.

Conclusion: The frequency of ADRs was high among the study cohort; however, these were managed effectively. Patients with recognized risk factors for ADRs occurrence need continuous clinical management efforts.

Efficient with low-cost removal and adsorption mechanisms of norfloxacin, ciprofloxacin and ofloxacin on modified thermal kaolin: experimental and theoretical studies

Quinolone antibiotics (QNs) can be potential hazard to environment and human. Combination of experimental and theoretical studies was used to analyze the adsorption properties of norfloxacin, ciprofloxacin and ofloxacin on modified thermally activated kaolin (KL). Main factors (calcination temperature, dose, pH, cations and regeneration) affecting the adsorption were discussed. Adsorption processes fit the pseudo-second order kinetic and Langmuir model well. The adsorption removal of norfloxacin, ciprofloxacin and ofloxacin can reach 88.53%, 89.43% and 91.46%, respectively. Cations inhibited adsorption, and AlS-KLB can maintain 80% efficiency in five cycles under optimal conditions. Simulations showed that the materials had good adsorption capacity for QNs, and the "①" of KL had the best capacity. Simulations explain the adsorption mechanism: F, H, O atoms of QNs are covalently bonded to O atoms from KL, Al₂O₃ and Al (OH)₃, C atoms from amorphous carbon and H atoms from C-H and Al (OH)₃. The Al atoms of Al₂O₃ and Al, Si atoms of KL are ionically bonded to F, H, O atoms of QNs. This study shed new light on the removal of QNs by providing low-cost and efficient modified KL and elucidating the adsorption mechanism in conjunction with DFT simulations.

Ciprofloxacin-associated Peripheral Neuropathy in a Child: A Case Report and Review of the Literature

Fluoroquinolones are reported to have peripheral nerve toxic effects that can be severe and permanent in adults. However, limited data exist for children. We describe a case of acute-onset peripheral neuropathy associated with ciprofloxacin in a 13-year-old boy who was characterized by severe dysesthesia and erythema of both hands and feet, but which resolved promptly after ceasing the antibiotic.

A VigiBase Descriptive Study of Fluoroquinolone-Associated Peripheral Nervous System Disorders

Background: Recent drug safety concerns described fluoroquinolone (FQ)-induced peripheral nervous system reactions. The objective of this study was to characterize such reports from VigiBase. Methods: The analysis included FQ-induced peripheral nervous system disorder adverse drug reaction (ADR) reports (up to July 2019). We looked into the disproportionality data in terms of proportional reporting ratio (PRR) and information component (IC) values, and descriptive analysis was performed for FQ-ADRs positive associations (ADRs, suspected FQs, potential risk factors, such as associated therapy and underlying disease). Results: Disproportionality analysis revealed 4374 reports (3531 serious) with peripheral nervous system ADRs associated with at least three FQs (neuropathy peripheral, 5492; neuralgia, 481; polyneuropathy, 220; sensory loss, 99; peripheral sensorimotor neuropathy, 39). Among these, both time-to-onset and duration of reaction were mostly between 1–7 days and ≥30 days. Most of the ADRs were not recovered/resolved at the time of reporting. Conclusion: The results augment the existing data on FQ safety concerns, specifically their potential effect on the nervous system.

Comparing LASSO and random forest models for predicting neurological dysfunction among fluoroquinolone users

BACKGROUND

Fluoroquinolones are associated with central (CNS) and peripheral (PNS) nervous system symptoms, and predicting the risk of these outcomes may have important clinical implications. Both LASSO and random forest are appealing modeling methods, yet it is not clear which method performs better for clinical risk prediction.

PURPOSE

To compare models developed using LASSO versus random forest for predicting neurological dysfunction among fluoroquinolone users.

METHODS

We developed and validated risk prediction models using claims data from a commercially insured population. The study cohort included adults dispensed an oral fluoroquinolone, and outcomes were CNS and PNS dysfunction. Model predictors included demographic variables, comorbidities and medications known to be associated with neurological symptoms, and several healthcare utilization predictors. We assessed the accuracy and calibration of these models using measures including AUC, calibration curves, and Brier scores.

RESULTS

The underlying cohort contained 16 533 (1.18%) individuals with CNS dysfunction and 46 995 (3.34%) individuals with PNS dysfunction during 120 days of follow-up. For CNS dysfunction, LASSO had an AUC of 0.81 (95% CI: 0.80, 0.82), while random forest had an AUC of 0.80 (95% CI: 0.80, 0.81). For PNS dysfunction, LASSO had an AUC of 0.75 (95% CI: 0.74, 0.76) versus an AUC of 0.73 (95% CI: 0.73, 0.74) for random forest. Both LASSO models had better calibration, with Brier scores 0.17 (LASSO) versus 0.20 (random forest) for CNS dysfunction and 0.20 (LASSO) versus 0.25 (random forest) for PNS dysfunction.

CONCLUSIONS

LASSO outperformed random forest in predicting CNS and PNS dysfunction among fluoroquinolone users, and should be considered for modeling when the cohort is modest in size, when the number of model predictors is modest, and when predictors are primarily binary.

How Safe are Fluoroquinolones for Diabetic Patients? A Systematic Review of Dysglycemic and Neuropathic Effects of Fluoroquinolones

Introduction

The US Food and Drug Administration issued safety warnings about neuropathy in 2013 and dysglycemia in 2018 caused by fluoroquinolone use, mainly based on case reports and case series. We conducted this systematic review to evaluate the safety of fluoroquinolones in diabetic patients by investigating their dysglycemic and neuropathic effects.

Methods

PubMed, Scopus, and Google Scholar were searched for randomized controlled trials and observational studies published from inception till September 2019 evaluating the safety of fluoroquinolones. Efficacy studies of fluoroquinolones reporting these adverse effects were also included. Primary outcomes were hypoglycemia, hyperglycemia, and neuropathy among patients with or without diabetes and treated with fluoroquinolones compared with placebo or other antibiotics. The Cochrane Collaboration tool for randomized controlled trials and modified Newcastle-Ottawa quality-assessment scale were used for assessment of the included studies.

Results and Discussion

A total of 725 studies were identified in the initial search. After screening of titles and abstracts and full-text review, 16 articles fulfilled the inclusion criteria. The sampled patients were aged 30-78 years. Hyperglycemia was reported in 1,588 patients that received fluoroquinolone among eight studies with 4,663 patients, and hypoglycemia was reported in 2,179 patients that received fluoroquinolones among eleven studies with 6,208 patients. Dysglycemia was not generally associated with diabetes mellitus per se. Nevertheless, patients with more comorbidities, especially those with chronic kidney disease, receiving antidiabetics and/or steroids had more glycemic events when treated with fluoroquinolones.

Conclusion

Moxifloxacin was found to be associated the most and ciprofloxacin the least with dysglycemia. fluoroquinolones must be used with great caution among diabetic patients who have comorbidities and are receiving antidiabetics and/or steroids. Further evidence is required from studies on neuropathy caused by fluoroquinolones.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Comparative neurological safety of fluoroquinolones versus therapeutic alternatives

BACKGROUND

Fluoroquinolones, one of the most commonly prescribed antibiotic classes, have been implicated in cases of central nervous system (CNS) and peripheral nervous system (PNS) adverse events, which highlights the need for epidemiologic studies of the neurological safety of fluoroquinolones.

PURPOSE

To evaluate the safety of fluoroquinolones with regard to risk of diagnosed neurological dysfunction.

METHODS

We conducted a propensity score-matched inception cohort study using claims data from a commercially insured population. Our study included adults prescribed an oral fluoroquinolone or comparator antibiotic between January 2000 and September 2015 for acute bacterial sinusitis, acute bacterial exacerbation of chronic bronchitis, uncomplicated urinary tract infection, or acute bronchitis. Our outcomes were CNS dysfunction, and four separate but complementary PNS dysfunction outcomes. Cox proportional hazards models were estimated after matching on propensity scores fitted using the variables age, sex, epilepsy, hereditary peripheral neuropathy, renal dysfunction, diabetes, gabapentinoid use, statin use, isoniazid use, and chemotherapy use.

RESULTS

Our cohort contained 976 568 individuals exposed to a fluoroquinolone antibiotic matched 1:1 with a comparator. Matching produced balance (standardized mean difference <0.1) on all variables included in the propensity score. The hazard ratio associated with fluoroquinolone exposure was 1.08 (95% confidence interval 1.05-1.11) for CNS dysfunction, and 1.09 (95% CI 1.07-1.11) for the most commonly occurring PNS dysfunction outcome.

CONCLUSIONS

Fluoroquinolone antibiotic use was associated with the development of neurological dysfunction versus comparator antibiotic use in the adult population.

Fluoroquinolone prophylaxis does not increase risk of neuropathy in children with acute lymphoblastic leukemia

Background

Fluoroquinolone antibiotics are frequently utilized in pediatric oncology patients as prophylaxis or step‐down therapy following broad spectrum beta‐lactam therapy for febrile neutropenia. Concerns regarding neurotoxicity limit the use of these agents. No studies have evaluated the association between fluoroquinolone use and neurotoxicity in pediatric oncology patients receiving other neurotoxic agents such as vincristine.

Methods

An observational cohort study comprising patients aged 0‐18 at diagnosis enrolled on a prospective study for treatment of acute lymphoblastic leukemia (ALL) at a pediatric comprehensive cancer center between October 2007 and November 2018. Data for neuropathic pain and sensory or motor neuropathy were collected prospectively, and a Cox proportional hazards regression model was used to evaluate associations between administration of fluoroquinolone antibiotics during induction therapy and subsequent development of vincristine‐induced peripheral neurotoxicity (VIPN).

Results

A total of 598 participants were enrolled, including 338 (57%) who received fluoroquinolones during induction therapy; of these 470 (79%) were diagnosed with VIPN and 139 (23%) were diagnosed with high‐grade (Grade 3+) VIPN. On unadjusted analyses, and analyses adjusted for age and race, there was no evidence of an association between fluoroquinolone exposure and subsequent VIPN (hazard ratio [HR] 0.8, 95% CI 0.5‐1.04, P = .08) or high‐grade VIPN (HR 1.1, 95% CI 0.4‐2.2, P = .87).

Conclusions

The results of this observational study do not show an association between exposure to fluoroquinolone antibiotics during induction therapy for ALL and subsequent development of vincristine‐induced peripheral neuropathies, and suggest that a large increase in VIPN is unlikely.

Neuropathological changes in dorsal root ganglia induced by pyridoxine in dogs

Background

Pyridoxine (PDX; vitamin B₆), is an essential vitamin. PDX deficiency induces various symptoms, and when PDX is misused it acts as a neurotoxicant, inducing severe sensory neuropathy.

Results

To assess the possibility of creating a reversible sensory neuropathy model using dogs, 150 mg/kg of PDX was injected subcutaneously into dogs for 7 days and body weight measurements, postural reaction assessments, and electrophysiological recordings were obtained. In addition, the morphology of dorsal root ganglia (DRG) and changes in glial fibrillary acidic protein (GFAP) immunoreactive satellite glial cells and ionized calcium-binding adapter molecule 1 (Iba-1) immunoreactive microglia/macrophages were assessed at 1 day, 1 week, and 4 weeks after the last PDX treatment. During the administration period, body weight and proprioceptive losses occurred. One day after the last PDX treatment, electrophysiological recordings showed the absence of the H-reflex in the treated dogs. These phenomena persisted over the four post-treatment weeks, with the exception of body weight which recovered to the pre-treatment level. Staining (CV and HE) results revealed significant losses of large-sized neurons in the DRG at 1 day and 1 week after PDX treatment cessation, but the losses were recovered at 4 weeks post-treatment. The Iba-1 and GFAP immunohistochemistry results showed pronounced increases in reactive microglia/macrophage and satellite glial cell at 1 day and 1 week, respectively, after the last PDX treatment, and thereafter, immunoreactivity decreased with increasing time after PDX treatment.

Conclusions

The results suggest that PDX-induced neuropathy is reversible in dogs; thus, dogs can be considered a good experimental model for research on neuropathy.

Fluoroquinolone antibiotics show genotoxic effect through DNA-binding and oxidative damage

The fluoroquinolones (FQs) are one the most successful class of synthetic antibiotics that primarily target the type II topoisomerases. With a pursuit to evaluate their genotoxicity, the present work established moderate to good DNA-damaging properties of some of the well-known and clinically prescribed fluoroquinolone antibiotics (2^nd and 3^rd generation). Hypochromic shift in UV-Vis absorption titration, fluorescence quenching in competitive ethidium bromide displacement assay (with calf-thymus DNA) and in-silico studies established DNA-intercalation with binding constants of the order 10⁴. A basic Structure Activity Relationship (SAR) has been derived from the docking results. MTT assay has been also done to evaluate the effect of these antibiotics on cell viability. The expression level of specific DNA-glycosylase enzymes responsible for repairing the oxidized DNA bases are quantified through western blot analysis. The studies revealed that fluoroquinolone antibiotics initiate the genotoxic effect at a concentration of above 50 μg/mL. Recruitment of APE1 and NEIL1 was found to be significantly increased to remove the oxidized nucleobases.

Toxicological effects of ciprofloxacin exposure to Drosophila melanogaster

The abuse of ciprofloxacin (CIP) may cause serious side effects and the mechanisms underlying these effects remain unclear. Here, we determinate the 48 h, 72 h and 96 h LC₅₀ values of CIP to Drosophila melanogaster and demonstrate a series of adverse effects after D. melanogaster was exposed to CIP at a sublethal concentration (3.2 mg mL^-1). Treated individuals showed shorter lifespan, delayed development and many of the treated larvae failed to pupate or hatch. Smaller body size was observed at every life stage when exposed to CIP and the size of pupae, the weight of third-instar larvae exhibited a perfectly dose-response relationship that the larger concentration exposed to, the smaller body size or lighter weight is. Moreover, reduction in fat body cell viability, elevated oxidative stress markers (SOD and CAT) and down-regulation of diap1, ex, two target genes of Yorkie (Yki), was observed in response to CIP exposure. Most importantly, we found two types of black spot in Drosophila and the proportion of larvae with a black spot was positively related to the treatment dose, which is new in the field. This study provides a scientific basis for the potential harm caused by abuse of quinolones with the goal of urging cautious use of antibiotics.

Lay Pharmacovigilance and the Dramatization of Risk: Fluoroquinolone Harm on YouTube

Sociologists have documented how the pharmaceutical industry has corrupted pharmacovigilance (PV), defined as the practices devoted to detecting and preventing adverse drug reactions (ADRs). In this article, I juxtapose the official postmarketing system of PV with firsthand accounts of ADRs as found in 60 YouTube vlogs created by 29 individuals who recount debilitating reactions to fluoroquinolones, a common class of antibiotics. Whereas official PV is said to contribute the banalization of risk, these vlogs exemplify the dramatization of risk. I consider the vlogs as instances of lay PV. They represent lay knowledge claims created in response to perceived failures in the official system of regulation. As such, lay PV shares commonalties with other articulations of lay expertise as a counter to medical authority. At the same time, this case also underscores how the YouTube platform offers new tools for the creation and distribution of lay expertise.

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.

Detection and quantification of 47 antibiotic residues in farmed European sea bass (Dicentrarchus labrax) using a multi-class and multi-residue UHPLC-MS/MS method

In the present study, a multi-class multi-residue method for the simultaneous detection and determination of antibiotics in European sea bass (Dicentrarchus labrax) was developed and validated. The method based on UHPLC-MS/MS proved to be a rapid, highly selective and sensitive tool, requiring minimum sample preparation, for screening and detection of 47 compounds from eight different classes. The validation was performed according to EU regulation 2002/657/EC, proving the method's suitability for application in routine analysis. The method was applied to the analysis of 30 samples of farmed European sea bass purchased in different supermarkets in Portugal. Antibacterial residues were detected in 6 of the 30 analysed samples, namely enrofloxacin and oxytetracycline, in concentrations ranging from 0.1 to 12 µg kg^-1.

Patients at Risk for Aortic Rupture Often Exposed to Fluoroquinolones during Hospitalization

Several studies have indicated that fluoroquinolone use may be associated with an increased risk of aortic aneurysm or dissection (AAD). Because patients with AAD or Marfan syndrome are at increased risk for aortic rupture, we performed a retrospective cohort study to determine the prevalence of systemic fluoroquinolone exposure and predictors of fluoroquinolone use in these patients. Data were obtained from the advisory board billing and administrative database, which contained information on 22 million adult hospitalizations in the United States for the study period (2009 to 2015). International Classification of Diseases (9/10) and Current Procedural Terminology codes were used to identify patients who had AAD or Marfan syndrome or underwent aortic repair. We identified 136,789 admissions for AAD, which involved 99,818 unique patients, 20% of whom received fluoroquinolone during a hospital admission. Of the 7,045 patients with dissection, 18% were exposed to fluoroquinolone. Of the 27,876 AAD patients who underwent aortic repair, 19% received fluoroquinolone during a hospitalization before the repair. In the AAD patients, having a diagnosis of pneumonia or urinary tract infection increased the likelihood of receiving fluoroquinolone during admission by 46% and 40%, respectively (P < 0.001). Additionally, we identified 2,871 admissions for Marfan syndrome, which involved 1,872 patients, 14% of whom received fluoroquinolone during an admission. In these patients, pneumonia and urinary tract infections also increased the risk of fluoroquinolone exposure. If the deleterious effects of fluoroquinolone on aortic integrity are substantiated, reducing fluoroquinolone use in hospitalized patients with aortic disorders will become an urgent safety issue for antibiotic stewardship programs.

Macrophage-targeted drugamers with enzyme-cleavable linkers deliver high intracellular drug dosing and sustained drug pharmacokinetics against alveolar pulmonary infections

Intracellular bacterial infections localized to the lung alveolar macrophage (AM) remain one of the most challenging settings for antimicrobial therapy. Current systemic antibiotic treatment fails to deliver sustained doses to intracellular bacterial reservoirs, which necessitates prolonged treatment regimens. Herein, we demonstrate a new intracellular enzyme-cleavable polymeric prodrug with tailored ciprofloxacin release profiles in the lungs and AM. The targeted polymeric prodrug, termed "drugamers", incorporates (1) hydrophilic mannose residues to solubilize the antibiotic cargo and to target and enhance AM uptake and intracellular delivery, and (2) enzyme-cleavable linkage chemistry to provide high and sustained intracellular AM drug dosing. Prodrug monomers, derived from the antibiotic ciprofloxacin, were synthesized with either an intracellular protease cleavable dipeptide linker or a hydrolytic phenyl ester linker. RAFT polymerization was used to copolymerize the prodrug monomers and mannose monomer to synthesize well-defined drugamers without requiring a post-polymerization conjugation step. In addition to favorable in vivo safety profiles following intratracheal administration, a single dose of the drugamers sustained ciprofloxacin dosing in lungs and AMs above the minimum inhibitory concentration (MIC) over at least a 48 h period. The enzyme-cleavable therapeutic achieved a >10-fold increase in sustained ciprofloxacin in AM, and maintained a significantly higher whole lung PK as well. Ciprofloxacin dosed in identical fashion displayed rapid clearance with a half-life of approximately 30 min. Notably, inhalation of the mannose-targeted ciprofloxacin drugamers achieved full survival (100%) in a highly lethal mouse model of pneumonic tularemia, contrasted with 0% survival using free ciprofloxacin. These findings demonstrate the versatility of the drugamer platform for engineering the intracellular pharmacokinetic profiles and its strong therapeutic activity in treating pulmonary intracellular infections.

Severe Acute Axonal Neuropathy Induced by Ciprofloxacin: A Case Report

Fluoroquinolones increase the risk of peripheral neuropathy. The present work aims to report a case of fluoroquinolone-related severe axonal neuropathy. The subject of this study was a 62-year-old man who exhibited generalized sensory disturbances 4 days after treatment by ciprofloxacin prescribed for urinary infection. Electrodiagnostic studies revealed severe motor-sensory axonal neuropathy with widespread fibrillation potentials in support of generalized motor polyradiculopathy. There was no evidence of conduction blocks or albuminocytologic dissociation in favor of an autoimmune inflammatory reaction. The only pathological biomarker was the reduction of serum folate. According to this case, we suggest that folate level could be routinely measured and supplementation should be performed in patients with fluoroquinolone-induced neuropathy.

Fluoroquinolone Use and Risk of Carpal Tunnel Syndrome: A Pharmacoepidemiologic Study

Fluoroquinolone-induced peripheral neuropathies and tendinopathies are well documented, but there are no epidemiologic studies on the risk of carpal tunnel syndrome (CTS). We conducted a case-control study of >6 million patients. Fluoroquinolone use is associated with increased risk of CTS (rate ratio, 1.34 [95% confidence interval, 1.31-1.37]).

Quinolone-Induced Painful Peripheral Neuropathy: A Case Report and Literature Review

We present a case report of a 20-year-old male with diabetes mellitus type 1, who developed severe painful peripheral neuropathy while on the second of a 10-day course with levofloxacin for the treatment of epididymitis. The intensity of the pain rapidly reached scores of 10/10 in a numeric scale 0/10, and the patient was transferred to an inpatient pain unit where he was treated aggressively with minimal improvement. A skin biopsy revealed small fiber neuropathy. Then the patient was treated with intravenous immunoglobulin, which improved the pain. Now the patient is on outpatient intravenous immunoglobulin infusions bimonthly and making a slow recovery.

Treatment of the Fluoroquinolone-Associated Disability: The Pathobiochemical Implications

Long-term fluoroquinolone-associated disability (FQAD) after fluoroquinolone (FQ) antibiotic therapy appears in recent years as a significant medical and social problem, because patients suffer for many years after prescribed antimicrobial FQ treatment from tiredness, concentration problems, neuropathies, tendinopathies, and other symptoms. The knowledge about the molecular activity of FQs in the cells remains unclear in many details. The effective treatment of this chronic state remains difficult and not effective. The current paper reviews the pathobiochemical properties of FQs, hints the directions for further research, and reviews the research concerning the proposed treatment of patients. Based on the analysis of literature, the main directions of possible effective treatment of FQAD are proposed: (a) reduction of the oxidative stress, (b) restoring reduced mitochondrion potential ΔΨ_m, (c) supplementation of uni- and bivalent cations that are chelated by FQs and probably ineffectively transported to the cell (caution must be paid to Fe and Cu because they may generate Fenton reaction), (d) stimulating the mitochondrial proliferation, (e) removing FQs permanently accumulated in the cells (if this phenomenon takes place), and (f) regulating the disturbed gene expression and enzyme activity.

An Update on Fluoroquinolones: The Emergence of a Multisystem Toxicity Syndrome

INTRODUCTION

The FDA (U.S. Food and Drug Administration) recently revised the boxed warning on fluoroquinolones to address serious safety concerns. This action was prompted by a growing number of reports involving patients with a constellation of symptoms now called fluoroquinolone associated disability.

METHODS

Internet and literature searches were performed to identify previous reports of quinolone induced multisystem toxicity syndromes. The 3 terms fluoroquinolone toxicity, quinolone toxicity syndrome and fluoroquinolone associated disability were used to query PubMed® and Google's search engine for available information.

RESULTS

Four primary sources emerged, including a recent FDA review, 2 case series and robust social media platforms. The FDA identified 1,122 fluoroquinolone disability reports from November 1, 1997 to May 30, 2015. A total of 178 cases qualified as fluoroquinolone associated disability after applying inclusion and exclusion criteria. Some estimate that there are as many as 45,000 cases of fluoroquinolone toxicity syndrome in the United States. All sources agree the affected population is generally young (mean age 40s to 50s), previously healthy and predominantly female. The FDA analysis revealed that average symptom duration was 14 months and longest duration was 9 years at the time of the review.

CONCLUSIONS

Fluoroquinolone toxicity syndromes do not affect the majority of exposed patients but are likely underappreciated. As providers seeking to heal and avoid harm to our patients, diligent prescribing practices are paramount, as are early recognition and discontinuation of the antibiotic.

Complications associated with antibiotic administration: neurological adverse events and interference with antiepileptic drugs

Antibiotic use is associated with toxic effects involving the peripheral and central nervous systems and it may interfere with antiepileptic drugs, causing significant variations in their serum levels and activity. Prompt identification of neurological complications during antibiotic therapy is important in order to make appropriate modifications to medication. Characteristics of the drug and the patient, including age and underlying diseases, may favour these complications. The main aim of this study was to review the neurological adverse events that may follow antibiotic administration, the mechanisms that cause them, and the possibility of prevention and treatment. Moreover, the interference of antibiotics with serum levels and the activity of antiepileptic drugs are discussed. The results demonstrate that antibiotic-associated adverse events involving the nervous system are relatively uncommon and are only rarely severe and irreversible, although neurotoxicity has been reported for several antibiotics. Moreover, for patients receiving antiepileptic drugs, monitoring of drug serum levels to avoid the risk of toxicity or inadequate therapy is mandatory during antibiotic treatment. Areas for future research include the effects of combined antibiotic therapies as well as multiple antiepileptic drugs in study populations with an adequate sample size, including neonates and infants, patients with pharmacoresistant epilepsy and elderly patients.

Intractable Acute Pain Related to Fluoroquinolone-Induced Peripheral Neuropathy

Fluoroquinolones are widely prescribed antibiotics, used for various infectious etiologies. These antibiotics carry the possibility of the serious adverse effect of peripheral neuropathy, with a true incidence not known owing to its rare existence. Recently, the Food and Drug Administration (FDA) has required alterations to drug labels to highlight this adverse effect of fluoroquinolones. This is a case report of a single patient at an inpatient neurology service at an urban academic medical center in the United States. The patient is a 20-year-old male, with well-controlled type 1 diabetes mellitus, presenting with a short duration of bilateral lower extremity pain following a 10-day course of levofloxacin for suspected epididymitis. The patient was initially diagnosed with complex regional pain syndrome and treated with a variety of pain medications, including lidocaine infusions, hydromorphone, methadone, and ketamine infusions. After review of the patient's history and limited response to medical management, the patient's condition was reclassified as an adverse effect from fluoroquinolone treatment. Pain of unknown etiology can be perplexing, both for the physician and the patient. Reporting of similar incidents attributed to medication adverse effects will increase the awareness of this type of neuropathy, avoid future cases of misdiagnosis, and enable early detection and treatment.

Kynurenine Aminotransferase Isozyme Inhibitors: A Review

Kynurenine aminotransferase isozymes (KATs 1–4) are members of the pyridoxal-5’-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies.

Fluoroquinolone-induced serious, persistent, multisymptom adverse effects

We present a case series of four previously healthy, employed adults without significant prior medical history in each of whom symptoms developed while on fluoroquinolones (FQs), with progression that continued following discontinuation evolving to a severe, disabling multisymptom profile variably involving tendinopathy, muscle weakness, peripheral neuropathy, autonomic dysfunction, sleep disorder, cognitive dysfunction and psychiatric disturbance. Physicians and patients should be alert to the potential for FQ-induced severe disabling multisymptom pathology that may persist and progress following FQ use. Known induction by FQs of delayed mitochondrial toxicity provides a compatible mechanism, with symptom profiles (and documented mechanisms of FQ toxicity) compatible with the hypothesis of an exposure-induced mitochondrial neurogastrointestinal encephalomyopathy.

Effects of ciprofloxacin-containing antimicrobial scaffolds on dental pulp stem cell viability-In vitro studies

OBJECTIVE

A combination of antibiotics, including but not limited to metronidazole (MET) and ciprofloxacin (CIP), has been indicated to eradicate bacteria in necrotic immature permanent teeth prior to regenerative procedures. It has been shown clinically that antibiotic pastes may lead to substantial stem cell death. The aim of this study was to synthesise scaffolds containing various concentrations of CIP to enhance cell viability while preserving antimicrobial properties.

DESIGN

Polydioxanone (PDS)-based electrospun scaffolds were processed with decreasing CIP concentrations (25-1 wt.%) and morphologically evaluated using scanning electron microscopy (SEM). Cytotoxicity assays were performed to determine whether the amount of CIP released from the scaffolds would lead to human dental pulp stem cell (hDPSC) toxicity. Similarly, WST-1 assays were performed to evaluate the impact of CIP release on hDPSC proliferation. Pure PDS scaffolds and saturated double antibiotic solution MET/CIP (DAP) served as both positive and negative controls, respectively. Antibacterial efficacy against E. faecalis (Ef) was tested.

RESULTS

A significant decrease in hDPSC' viability at concentrations 5-25 wt.% was observed. However, concentrations below 5wt.% did not impair cell viability. Data from the WST-1 assays indicated no detrimental impact on cell proliferation for scaffolds containing 2.5 wt.% CIP or less. Significant antimicrobial properties were seen for CIP-scaffolds at lower concentrations (i.e., 1 and 2.5 wt.%).

CONCLUSION

The obtained data demonstrated that a reduced concentration of CIP incorporated into PDS-based scaffolds maintains its antimicrobial properties while enhancing viability and proliferation of dental pulp stem cells.

A Severe Accident Caused by an Ocellate River Stingray (Potamotrygon motoro) in Central Brazil: How Well Do We Really Understand Stingray Venom Chemistry, Envenomation, and Therapeutics?

Freshwater stingrays cause many serious human injuries, but identification of the offending species is uncommon. The present case involved a large freshwater stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in the Araguaia River in Tocantins, Brazil. Appropriate first aid was administered within ~15 min, except that an ice pack was applied. Analgesics provided no pain relief, although hot compresses did. Ciprofloxacin therapy commenced after ~18 h and continued seven days. Then antibiotic was suspended; however, after two more days and additional tests, cephalosporin therapy was initiated, and proved successful. Pain worsened despite increasingly powerful analgesics, until debridement of the wound was performed after one month. The wound finally closed ~70 days after the accident, but the patient continued to have problems wearing shoes even eight months later. Chemistry and pharmacology of Potamotrygon venom and mucus, and clinical management of freshwater stingray envenomations are reviewed in light of the present case. Bacterial infections of stingray puncture wounds may account for more long-term morbidity than stingray venom. Simultaneous prophylactic use of multiple antibiotics is recommended for all but the most superficial stingray wounds. Distinguishing relative contributions of venom, mucus, and bacteria will require careful genomic and transcriptomic investigations of stingray tissues and contaminating bacteria.

Permanent Peripheral Neuropathy: A Case Report on a Rare but Serious Debilitating Side-Effect of Fluoroquinolone Administration

The health risks and side effects of fluoroquinolone use include the risk of tendon rupture and myasthenia gravis exacerbation, and on August 15, 2013, the Food and Drug Administration updated its warning to include the risk of permanent peripheral neuropathy. We present a case of fluoroquinolone-induced peripheral neuropathy in a patient treated for clinically diagnosed urinary tract infection with ciprofloxacin antibiotic.

Fluoroquinolone antibiotics and type 2 diabetes mellitus

Exposure to fluoroquinolone antibiotics is postulated as a risk factor for subsequent development of type 2 diabetes. It is hypothesized that fluoroquinolones induce an intracellular magnesium deficit that can lead to insulin resistance. A temporal correlation is reported between the rate of outpatient prescription of quinolones and the incidence of diabetes during the period 1980-2011 with a lag of approximately two years (R(2)=0.86, P<10(-9)). The increase in incidence of diabetes after 1990 and the recent decrease in the number of new cases are both reflected in the fluoroquinolone prescription rates. A geographical correlation is reported (adj. R(2)=0.7, P<0.0001) between rates of increase in prevalence of diabetes in each U.S. state and a model using only local rates of outpatient fluoroquinolone prescription, local rates of increase in the prevalence of obesity, and local rates of population growth as predictor variables. Prescription rates of non-quinolone antibiotics correlated less well with the local rates of increase in prevalence of diabetes. The data are consistent with fluoroquinolone exposure predisposing an individual to develop diabetes with a probability that strongly depends upon factors that also lead to an increase in obesity. According to the hypothesis, much of the increase in the incidence of type 2 diabetes in the U.S. from 1990 to the present can be attributed to fluoroquinolone exposure.

Comparative pharmacokinetics and bioavailability of gemifloxacin administered as an intravenous 200 mg formulation or an oral 320 mg tablet

BACKGROUND

Gemifloxacin is a synthetic fluoroquinolone antimicrobial agent, which has potent activity against most Gram-negative and Gram-positive organisms. It is indicated for the treatment of community-acquired pneumonia and acute bacterial exacerbation of chronic bronchitis.

OBJECTIVE

The aim of this study was to assess the clinical potential of a new gemifloxacin 200 mg intravenous formulation by comparing its pharmacokinetic characteristics with those of the branded Factive(®) gemifloxacin tablet.

METHODS

A single-dose, open-label, randomized-sequence, two-period crossover study was performed with 17 healthy male volunteers. The two treatment periods were separated by a 1-week washout period. Blood samples were taken for up to 48 h post-dose. Plasma gemifloxacin concentrations were determined by a validated high-performance liquid chromatography-tandem mass spectrometry method. To calculate the pharmacokinetic parameters, noncompartmental analysis was performed. The two formulations were considered to be pharmacokinetically equivalent if the 90 % confidence intervals (CIs) of the log-transformed ratios (intravenous/oral formulations) of the area under the plasma concentration-time curve (AUC) from time zero to the time of the last measurable concentration (AUClast) and the AUC from time zero to infinity (AUC∞) were within the standard bioequivalence range (0.8-1.25). Safety and tolerability were evaluated on the basis of physical examinations, vital signs, electrocardiograms, clinical laboratory tests and adverse event monitoring.

RESULTS

Seventeen subjects were enrolled, and 15 subjects completed the study. Sixteen subjects received intravenous 200 mg gemifloxacin and 15 received oral 320 mg gemifloxacin. The 15 subjects in the pharmacokinetic analysis set had a mean (standard deviation [SD]) age, height and weight of 27.2 (5.3) years, 173.5 (4.4) cm and 67.3 (7.4) kg, respectively. Both formulations had similar pharmacokinetic profiles. For the intravenous formulation, the mean (SD) AUClast, AUC∞ and maximum plasma concentration (C max) values were 9.12 (4.03) μg·h/mL, 9.26 (4.07) μg·h/mL and 2.90 (1.65) μg/mL, respectively, while these values for the oral formulation were 9.44 (3.34) μg·h/mL, 9.60 (3.49) μg·h/mL and 2.03 (0.95) μg/mL, respectively. For the intravenous and oral formulations, the median (range) time to reach C max (t max) values were 0.9 (0.7-1.0) and 1.0 (0.5-2.0) h, respectively. The mean relative bioavailability was 68.99 %. The 90 % CI of the ratios of the log-transformed values of AUClast and AUC∞ was 0.82-1.07. There were no serious adverse events. The intravenous and oral formulations were associated with treatment-emergent adverse event incidences of 63 % (10/16) and 13 % (2/15), respectively. After the intravenous formulation was administered, application site pain and paraesthesia were the most frequently reported adverse events (31 and 25 %, respectively). All adverse events resolved spontaneously without treatment.

CONCLUSION

Intravenous 200 mg and oral 320 mg formulations of gemifloxacin are equivalent in terms of AUC following a single dose in healthy male subjects.

Medication, toxic, and vitamin-related neuropathies

PURPOSE OF REVIEW

Although medication, toxic, and vitamin-related neuropathies are rare causes of neuropathy, they are important to recognize because they are treatable and preventable. It is often difficult to conclusively demonstrate that a particular agent is the cause of neuropathy, but understanding the specific electrodiagnostic and clinical patterns produced by these agents is critical for making these assessments.

RECENT FINDINGS

The clinical and electrodiagnostic features for many of these neuropathies have been well established. The exact mechanism by which some of these agents produce neuropathy is only now beginning to be revealed. These mechanisms are critical for both understanding the normal function of nerves as well as eventually devising specific treatments.

SUMMARY

A large number of medications and toxins can produce neuropathy. This article reviews the clinical characteristics, electrodiagnostic features, and mechanism of action (when known) of those agents that produce the most severe, or perhaps the most unique features of, neuropathy.

Levofloxacin-induced delirium: is it a dangerous drug in patients with renal dysfunction?

The central nervous system (CNS) toxicity of fluoroquinolones is well known but usually occurs benign. In the literature, there are a few number of severe CNS toxicity cases related to fluoroquinolones. Levofloxacin is a third-generation fluorinated quinolone antibiotic, is the active levo stereoisomer of ofloxacin, and has one of the most favorable adverse reaction profiles. We describe a case of delirium associated with levofloxacin in a 55-year-old man who was hospitalized in our medical clinic for pneumonia.

Linezolid-associated peripheral and optic neuropathy in children

OBJECTIVE

Peripheral neuropathy (PN) and optic neuropathy (ON) associated with linezolid use are described in the adult literature; however limited information is available in pediatrics. The purpose of this communication is to summarize pediatric cases of linezolid-associated neuropathy and to increase awareness of these neurologic side effects so that clinicians can most appropriately balance the benefits and risks of linezolid in the pediatric population.

METHODS

A search of the FDA Adverse Events Reporting System was performed for all pediatric cases of neuropathy from April 2000-2009. AERS includes both inpatient and outpatient data. Inpatient utilization patterns for linezolid were also assessed from January 2000 to December 2008.

RESULTS

Eight pediatric cases of linezolid-associated neuropathy were identified. Treatment duration ranged from 4 weeks to 1 year. Five patients had PN alone, one had only ON and two had both. Symptoms of PN included pain, numbness, weakness, and paresthesias. Symptoms of ON included decreased visual acuity and color vision. Three children had other adverse events associated with linezolid including acidosis, anemia, and leukopenia. Outcomes were reported in 5 cases. Resolution of symptoms occurred between 2 weeks and 6 months after discontinuation of linezolid. Utilization data showed that during the study period, overall inpatient utilization of linezolid had increased.

CONCLUSIONS

While linezolid may be used to treat serious infections often needing extended courses of therapy, potential safety concerns should be kept in mind. In the circumstance of prolonged use of linezolid in children, it is likely that more cases of neuropathy may occur.

Implementation of guidelines for management of possible multidrug-resistant pneumonia in intensive care: an observational, multicentre cohort study

BACKGROUND

The American Thoracic Society and Infectious Diseases Society of America provide guidelines for management of hospital-acquired, ventilator-associated, and health-care-associated pneumonias, consisting of empirical antibiotic regimens for patients at risk for multidrug-resistant pathogens. We aimed to improve compliance with these guidelines and assess outcomes.

METHODS

We implemented a performance-improvement initiative in four academic medical centres in the USA with protocol-based education and prospective observation of outcomes. Patients were assessed for severity of illness and followed up until death, hospital discharge, or day 28. We included patients in intensive-care units who were at risk for multidrug-resistant pneumonia and were treated empirically.

FINDINGS

303 patients at risk for multidrug-resistant pneumonia were treated empirically, and prescribed treatment was guideline compliant in 129 patients and non-compliant in 174 patients. 44 (34%) patients died before 28 days in the compliance group and 35 (20%) died in the non-compliance group. Five patients in the compliance group and seven in the non-compliance group were lost to follow-up after day 14. Kaplan-Meier estimated survival to 28 days was 65% in the compliance group and 79% in the non-compliance group (p=0·0042). This difference persisted after adjustment for severity of illness. Median length of stay and duration of mechanical ventilation did not differ between groups. Compliance failures included non-use of dual treatment for Gram-negative pathogens in 154 patients and absence of meticillin-resistant Staphylococcus aureus coverage in 24 patients. For patients in whom pathogens were subsequently identified, empirical treatment was active in 79 (81%) of 97 of patients receiving compliant therapy compared with 109 (85%) of 128 of patients receiving non-compliant therapy.

INTERPRETATION

Because adherence with empirical treatment was associated with increased mortality, we recommend a randomised trial be done before further implementation of these guidelines.

FUNDING

Pfizer, US Medical.

Modification of innervation pattern by fluoroquinolone treatment in the rat salivary glands

Fluoroquinolone antibiotics (FQAs) are widely used in dental and medical therapy. Despite their known severe adverse actions on the central and peripheral nervous system, little attention has been directed toward the potential toxic side effects of these compounds on the oral tissues. As the saliva secretion is controlled by the nervous system and neuropeptides, the neurotoxic effect of pefloxacin (PEF), a representative member of FQAs, was studied in rats in the present work. Previously, we demonstrated a significant weight loss of parotid gland tissue, a marked decrease in 3H-thymidine incorporation, a decreased volume of saliva and amylase activity of the glandular tissue in response to PEF. Animals received intraperitoneal injection of PEF (20 mg/100 g body weight daily) for 3 and 7 days. Normal histology, and neurofilament 200, substance P (SP) and calcitonin gene-related polypeptide (CGRP) containing nerve fibers were detected with immunohistochemical methods. A marked decrease of the weights in salivary glands and the acinar diameters were measured. Similarly, a strong and significant decrease of the number of SP and CGRP containing nerve fibers were detected. These findings suggest that the impaired morphology and innervation pattern of salivary glands is related to the neurotoxic adverse effect of FQA treatment.

A Review of Levofloxacin for the Treatment of Bacterial Infections

Completing its initial phases of drug development in the mid 1990s as the one of the first fluoroquinolones that could be used with confidence to treat respiratory tract infections, levofloxacin went on to become one of the most widely prescribed antibiotics in the world. Available in both oral (po) and intravenous (IV) formulations and with characteristics of over 90% bioavailability, distribution into both extracellular and intracellular pulmonary compartments, highly predictable pharmacokinetics with over 90% of the drug being excreted unchanged in urine, and reliable activity against a broad spectrum of clinically important pathogens, levofloxacin has been used successfully to treat patients with a variety of serious infectious diseases as well as common infections most often treated outside of the hospital setting. Results of clinical trials involving patients with respiratory tract, urinary tract, and skin infections have consistently shown rates of clinical success and bacteriological eradication that were comparable to other widely used broad-spectrum agents. Regimens of levofloxacin, initially involving total daily doses of 250 mg to 500 mg, but more recently regimens involving 750 mg doses, have been shown to be safe and effective. Nearly a decade and a half of clinical experience has defined a safety and tolerability profile that permits data-driven assessment of the risks and benefits of using levofloxacin. As resistance to currently available fluoroquinolones has emerged, the clinical value of levofloxacin deserves continued evaluation. However, consistently high rates of susceptibility of clinically important bacteria, especially among those bacteria that commonly cause respiratory tract infections, such as Streptococcus pneumoniae and Haemophilus influenzae, suggest that this agent will continue to be a widely used well past the 20-year anniversary of its introduction into the antibacterial armamentarium.