Safety of fluoroquinolones: An update

Long-term toxicity of fluoroquinolones: a comprehensive review

Fluoroquinolones (FQs) are highly potent bactericidal antibiotics with broad-spectrum activity against Gram-negative/positive bacteria. The Food and Drug Administration (FDA) anticipated the presence of a long-lasting incapacity of Fluoroquinolone Associated Toxicity (FQAT), which is not officially documented yet. This review aimed to précis the existing information on FQA long-term toxicity, such as cardiotoxicity, aortic aneurysm, tendon rupture, nephrotoxicity, hepatotoxicity, peripheral neuropathy, vagus nervous dysfunction, reactive oxygen species (ROS), phototoxicity, glucose hemostasis, and central nervous system (CNS) toxicity. We are focused on the CNS toxicity of FQs, either due to the direct action of the FQs on CNS receptors or by other drug co-administration, including nonsteroidal anti-inflammatory disease (NSAIDs) and theophylline. Due to the nature of the R7 side chain, FQs containing unsubstituted 7-piperazine and 7-pyrrolidine have the most significant effect. The gamma-aminobutyric acid-A (GABAA) receptor and CNS effects are inhibited through at least three possible mechanisms. Firstly, by the pharmacological action of the quinolone directly. Secondly, FQ-NSAIDs interact pharmacodynamically in which the interaction between the FQ and a receptor is significantly altered by the presence of another drug that interacts with the same receptor. An example may be the interaction between NSAIDs and some FQs. Thirdly, a pharmacokinetic drug-drug interaction leads to a higher concentration of quinolone or the other drug. An example may be the interaction between theophylline and benzodiazepines with some FQs.

Reactive metabolite of trovafloxacin activates inflammasomes: Implications for trovafloxacin-induced liver injury

Trovafloxacin is a quinolone antibiotic drug with broad-spectrum activity, which was withdrawn from a global market relatively soon after approval because of serious liver injury. The characteristics of trovafloxacin-induced liver injury are consistent with an idiosyncratic reaction; however, the details of the mechanism have not been elucidated. We examined whether trovafloxacin induces the release of damage-associated molecular patterns (DAMPs) that activate inflammasomes. We also tested ciprofloxacin, levofloxacin, gatifloxacin, and grepafloxacin for their ability to activate inflammasomes. Drug bioactivation was performed with human hepatocarcinoma functional liver cell-4 (FLC-4) cells, and THP-1 cells (human monocyte cell line) were used for the detection of inflammasome activation. The supernatant from the incubation of trovafloxacin with FLC-4 cells for 7 days increased caspase-1 activity and production of IL-1ß by THP-1 cells. In the supernatant of FLC-4 cells that had been incubated with trovafloxacin, heat shock protein (HSP) 40 was significantly increased. Addition of a cytochrome P450 inhibitor to the FLC-4 cells prevented the release of HSP40 from the FLC-4 cells and inflammasome activation in THP-1 cells by the FLC-4 supernatant. These results suggest that reactive metabolites of trovafloxacin can cause the release of DAMPs from hepatocytes that can activate inflammasomes. Inflammasome activation may be an important step in the activation of the immune system by trovafloxacin, which, in some patients, can cause immune-related liver injury.

Risk factors associated with a history of iliotibial band syndrome (hITBS) in distance runners: a cross-sectional study in 76 654 race entrants - a SAFER XXXIII study

BACKGROUND

Despite the numerous health benefits of distance running, it is also associated with the development of 'gradual onset running-related injuries' (GORRIs) one of which is Iliotibial Band Syndrome (ITBS). Novel risk factors associated with a history of ITBS (hITBS) have not been described in a large cohort of distance runners.

OBJECTIVE

To identify risk factors associated with hITBS in distance runners.

DESIGN

Descriptive cross-sectional study.

SETTING

21.1 km and 56 km Two Oceans Marathon races (2012-2015).

PARTICIPANTS

106 743 race entrants completed the online pre-race medical screening questionnaire. A total of 1 314 runners confirmed an accurate hITBS diagnosis.

METHODS

Selected risk factors associated with hITBS explored included: demographics (race distance, sex, age groups), training/running variables, history of existing chronic diseases (including a composite chronic disease score) and history of any allergy. Prevalence (%) and prevalence ratios (PR; 95% CI) are reported (uni- & multiple regression analyzes).

RESULTS

1.63% entrants reported hITBS in a 12-month period. There was a higher (p < 0.0001) prevalence of hITBS in the longer race distance entrants (56 km), females, younger entrants, fewer years of recreational running (PR = 1.07; p = 0.0009) and faster average running speed (PR = 1.02; p = 0.0066). When adjusted for race distance, sex, age groups, a higher chronic disease composite score (PR = 2.38 times increased risk for every two additional chronic diseases; p < 0.0001) and a history of allergies (PR = 1.9; p < 0.0001) were independent risk factors associated with hITBS.

CONCLUSION

Apart from female sex, younger age, fewer years of running and slower running speed, two novel independent risk factors associated with hITBS in distance runners are an increased number of chronic diseases and a history of allergies. Identifying athletes at higher risk for ITBS can guide healthcare professionals in their prevention and rehabilitation efforts.

Non-chemotherapy adjuvant agents in TP53 mutant Ewing sarcoma

Ewing sarcoma (EWS) is a malignant tumor arising in bone or soft tissue that occurs in adolescent and young adult patients as well as adults later in life. Although non-metastatic EWS is typically responsive to treatment when newly diagnosed, relapsed cases have an unmet need for which no standard treatment approach exists. Recent phase III clinical trials for EWS comparing 7 vs 5 chemotherapy drugs have failed to improve survival. To extend the durability of remission for EWS, we investigated 3 non-chemotherapy adjuvant therapy drug candidates to be combined with chemotherapy. The efficacy of these adjuvant drugs was investigated via anchorage-dependent growth assays, anchorage-independent soft-agar colony formation assays and EWS xenograft mouse models. Enoxacin and entinostat were the most effective adjuvant drug in both long-term in vitro and in vivo adjuvant studies. In the context that enoxacin is an FDA-approved antibiotic, and that entinostat is an investigational agent not yet FDA-approved, we propose enoxacin as an adjuvant drug for further preclinical and clinical investigation in EWS patients.

Effect of four fluoroquinolones on the viability of bladder cancer cells in 2D and 3D cultures

Introduction

The anticancer properties of fluoroquinolones and the high concentrations they achieve in urine may help in bladder cancer therapy. This study aimed to analyze the properties of 4 fluoroquinolones as potential candidates for supportive treatment of bladder cancer.

Methods

Comparative analyses were performed on the cytotoxic effects of norfloxacin, enrofloxacin, moxifloxacin, and ofloxacin on normal and cancer urothelial cell lines. In 2D culture, the cytotoxic properties of fluoroquinolones were evaluated using MTT assay, real-time cell growth analysis, fluorescence and light microscopy, flow cytometry, and molecular analysis. In 3D culture, the properties of fluoroquinolones were tested using luminescence assays and confocal microscopy.

Results and Discussion

All tested fluoroquinolones in 2D culture decreased the viability of both tested cell lines in a dose- and timedependent manner. Lower concentrations did not influence cell morphology and cytoskeletal organization. In higher concentrations, destruction of the actin cytoskeleton and shrinkage of the nucleus was visible. Flow cytometry analysis showed cell cycle inhibition of bladder cancer cell lines in the G2/M phase. This influence was minimal in the case of normal urothelium cells. In both tested cell lines, increases in the number of late apoptotic cells were observed. Molecular analysis showed variable expression of studied genes depending on the drug and concentration. In 3D culture, tested drugs were effective only in the highest tested concentrations which was accompanied by caspase 3/7 activation and cytoskeleton degradation. This effect was hardly visible in non-cancer cell lines. According to the data, norfloxacin and enrofloxacin had the most promising properties. These two fluoroquinolones exhibited the highest cytotoxic properties against both tested cell lines. In the case of norfloxacin, almost all calculated LC values for bladder cancer cell lines were achievable in the urine. Enrofloxacin and norfloxacin can be used to support chemotherapy in bladder cancer patients.

Chronic diseases and allergies are risk factors predictive of a history of Medial Tibial Stress Syndrome (MTSS) in distance runners: SAFER study XXIV

BACKGROUND

Medial Tibial Stress Syndrome (MTSS) is one of the most common causes of exercise-associated lower leg pain in distance runners.

AIM

To identify risk factors predictive of a history of MTSS in distance runners entering the Two Oceans Marathon races (21.1 km and 56 km).

DESIGN

Cross-sectional study.

SETTING

2012 to 2015 Two Oceans Marathon races (21.1 km and 56 km).

PARTICIPANTS

Consenting race entrants.

METHODS

106,743 race entrants completed an online pre-race medical screening questionnaire. 76,654 consenting runners (71.8%) were studied. 558 verified MTSS injuries were reported in the previous 12 months. Risk factors predictive of a history of MTSS were explored using uni - & multivariate analyses: demographics (race distance, sex, and age groups), training/racing history, history of chronic diseases, allergies, and medication use.

RESULTS

Independent risk factors predictive of a history of MTSS (adjusted for sex, age group, and race distance) were a higher chronic disease composite score (PR = 3.1 times increase risk for every two additional chronic diseases; p < 0.0001) and a history of allergies (PR = 1.9; p < 0.0001). Chronic diseases (PR > 2) predictive of a history of MTSS were: symptoms of CVD (PR = 4.2; p < 0.0001); GIT disease (PR = 3.3; p < 0.0001); kidney/bladder disease (PR = 3.3; p < 0.0001); nervous system/psychiatric disease (PR = 3.2; p < 0.0001); respiratory disease (PR = 2.9; p < 0.0001) a history of CVD (PR = 2.9; p < 0.0001); and risk factors of CVD (PR = 2.4; p < 0.0001) (univariate analysis). Average running speed was associated with higher risk of MTSS.

CONCLUSION

Novel independent risk factors predictive of a history of MTSS in distance runners (56 km, 21.1 km) were multiple chronic diseases and a history of allergies. Identifying athletes at higher risk for MTSS can guide healthcare professionals in their prevention and rehabilitation efforts.

Positron Emission Tomography-Based Pharmacokinetic Analysis To Assess Renal Transporter-Mediated Drug-Drug Interactions of Antimicrobial Drugs

Transporter-mediated drug-drug interactions (DDIs) are of concern in antimicrobial drug development, as they can have serious safety consequences. We used positron emission tomography (PET) imaging-based pharmacokinetic (PK) analysis to assess the effect of different drugs, which may cause transporter-mediated DDIs, on the tissue distribution and excretion of [18F]ciprofloxacin as a radiolabeled model antimicrobial drug. Mice underwent PET scans after intravenous injection of [18F]ciprofloxacin, without and with pretreatment with either probenecid (150 mg/kg), cimetidine (50 mg/kg), or pyrimethamine (5 mg/kg). A 3-compartment kidney PK model was used to assess the involvement of renal transporters in the examined DDIs. Pretreatment with probenecid and cimetidine significantly decreased the renal clearance (CLrenal) of [18F]ciprofloxacin. The effect of cimetidine (-86%) was greater than that of probenecid (-63%), which contrasted with previously published clinical data. The kidney PK model revealed that the decrease in CLrenal was caused by inhibition of basal uptake transporters and apical efflux transporters in kidney proximal tubule cells. Changes in the urinary excretion of [18F]ciprofloxacin after pretreatment with probenecid and cimetidine resulted in increased blood and organ exposure to [18F]ciprofloxacin. Our results suggest that multiple membrane transporters mediate the tubular secretion of ciprofloxacin, with possible species differences between mice and humans. Concomitant medication inhibiting renal transporters may precipitate DDIs, leading to decreased urinary excretion and increased blood and organ exposure to ciprofloxacin, potentially exacerbating adverse effects. Our study highlights the strength of PET imaging-based PK analysis to assess transporter-mediated DDIs at a whole-body level.

Photosensitivity During Quinolone Therapy in Diabetic Foot Patients May Falsely Indicate Treatment Failure

Acute bacterial skin and skin structure infections (ABSSSI), also referred to as skin and soft tissue infections, or skin and skin structure infections, with or without osteomyelitis (OM) in diabetic foot are complications of diabetes. Quinolones are a widely used class of antibiotics in ABSSSI and OM, and photosensitivity is among their adverse reactions. Its appearance may falsely indicate treatment failure. We describe 2 such cases. The first patient is a 49-year-old male with type 2 diabetes mellitus (DM), who presented with left lower limb ulcer with fever (39 °C) over a week. He began treatment with ciprofloxacin, clindamycin, and linezolid. Although his clinical condition and laboratory tests improved, the redness of the left lower limb increased. Clinical examination revealed redness on the face and the parts of the body that had been exposed to sunlight. The patient continued the same antimicrobial therapy and was given instructions to avoid exposure to sunlight. Redness and infection improved, and the patient was discharged. The second case is a 72-year-old male with a history of type 2 DM, admitted to hospital because of an infected ulcer of the first toe of the right limb. The patient received intravenous treatment with levofloxacin and clindamycin. On the fourth hospital day, the patient presented redness (with eczematous plaques) on his left lower limb. Clinical examination revealed that the patient's bed was placed near a window and his left limb was exposed to direct sunlight. Patient's bed was changed to avoid sun exposure. Symptoms began to improve over the next few days.

Safety of oral nemonoxacin: A systematic review of clinical trials and postmarketing surveillance

Background: Postmarketing safety analysis is an effective supplement for new drugs in clinical practice. Therefore, we aimed to systematically assess the safety of oral nemonoxacin malate, the first approved C-8-methoxy non-fluorinated quinolone, in clinical studies and via postmarketing safety surveillance. Methods: We electronically and manually searched and screened safety data (including premarketing and postmarketing data) of oral nemonoxacin from clinical registries. We standardized and summarized the reported adverse events according to the Medical Dictionary for Regulatory Activities System Organ Class and Preferred Terms. We summarized and reported the number and frequency (%) of the AEs and serious AEs in patients with community-acquired pneumonia and in specific patients. Results: Three Phase II/III comparator studies (n = 670, nemonoxacin), one Phase IV study (n = 461), two special population pharmacokinetic studies (n = 40), four observational studies (n = 1,852), and one 5-year postmarketing surveillance project (n = 257,420) were included in this study. The Phase II/III studies showed that the commonly reported drug-related AEs were similar for oral 500 mg nemonoxacin and levofloxacin treatments, which mainly included increased alanine aminotransferase levels (4.4% vs. 2.5%), neutropenia (2.5% vs. 4.4%), nausea (2.5% vs. 1.6%), and leukopenia (2.3% vs. 3.2%). No drug-related deaths were reported. Postmarketing safety surveillance revealed that known adverse drug reaction characteristics were generally unchanged. Pharmacokinetic data suggested that dose adjustment was not necessary in elderly patients, which was confirmed by a Phase IV study in an elderly population, in patients with renal impairment with CLcr ≥50 ml/min, and in those with mild-to-moderate hepatic impairment. Conclusion: Clinical trial data of approximately 1,450 patients and postmarketing data of >257,420 patients suggest that nemonoxacin is generally well tolerated and can be a suitable alternative to fluoroquinolones for patients with CAP.

Preclinical safety evaluation of levonadifloxacin, a novel anti-methicillin-resistant Staphyloccocus aureus benzoquinolizine fluoroquinolone by intravenous and oral administration

Fluoroquinolone (FQ) antibacterials have drawn heightened attention from various international regulatory agencies due to their class-specific side effects. Levonadifloxacin is a novel broad spectrum benzoquinolizine FQ active against methicillin-resistant Staphyloccocus aureus (MRSA). Owing to FQ-associated safety concerns, extensive preclinical safety pharmacology (central nervous system and cardiac safety) and toxicology studies (subacute repeat-dose toxicity, genotoxicity, phototoxicity and chondrotoxicity) of levonadifloxacin were performed at relatively high doses. Intravenous (IV) and oral studies were conducted using WCK 771 (l-arginine salt of levonadifloxacin) and WCK 2349 (l-alanine ester prodrug of levonadifloxacin), respectively. Safety pharmacology studies following single dose revealed no adverse effects on central nervous system (including seizure) in mice and cardiovascular system (hERG and monkey telemetry). In repeat-dose toxicity studies, except for IV bolus dosing related effects in rat (hyperactivity, mild convulsion, polypnoea and injection site irritation) and dog (emesis and salivation), no other adverse findings limiting the dosing duration were observed. No major biochemical, haematological, gross or histopathological changes suggestive of damage to vital organs were observed in either WCK 771- or WCK 2349-treated groups. WCK 771 and WCK 2349 were found to be nongenotoxic; however, they showed weak phototoxicity that was comparable with levofloxacin. WCK 771 showed chondrotoxicity in the Beagle dog pups on repeat-dose administration; however, the severity level was lower than ofloxacin. Overall, preclinical safety studies helped establish wider safety margin for WCK 771 and WCK 2349 that supports administration of higher therapeutic doses in humans by both IV and oral routes, thereby enabling safe anti-MRSA treatment.

Quinolones as a Potential Drug in Genitourinary Cancer Treatment-A Literature Review

Quinolones, broad-spectrum antibiotics, are frequently prescribed by urologists for many urological disorders. The mechanism of their bactericidal activity is based on the inhibition of topoisomerase II or IV complex with DNA, which consequently leads to cell death. It has been observed that these antibiotics also act against the analogous enzymes present in eukaryotic cells. Due to their higher accumulation in urine and prostate tissue than in serum, these drugs seem to be ideal candidates for application in genitourinary cancer treatment. In this study, an extensive literature review has been performed to collect information about concentrations achievable in urine and prostate tissue together with information about anticancer properties of 15 quinolones. Special attention was paid to the application of cytotoxic properties of quinolones for bladder and prostate cancer cell lines. Data available in the literature showed promising properties of quinolones, especially in the case of urinary bladder cancer treatment. In the case of prostate cancer, due to low concentrations of quinolones achievable in prostate tissue, combination therapy with other chemotherapeutics or another method of drug administration is necessary.

Regeneration difficulties in patients with FQAD can limit the use of iPSc-based cell therapy

Etiopathogenesis of fluoroquinolone-associated disability (FQAD) syndrome is not fully understood, yet research could progress by utilizing induced pluripotent stem cells (iPSc) from people with this syndrome. Similarly, iPSc, or rather their derivatives, could be used in their therapy, not only for FQAD but also for other disorders in which generated autologous iPSc and their derivatives might be helpful. Urine was collected from ten donors with FQAD, and reprogramming of these cells was conducted with the use of Epi5TM Episomal iPSC Reprogramming Kit. IPSc were generated in one out of ten person’s urine cells. While urinary cells are considered the easiest mature cells to be reprogrammed into iPSc, the urinary cells from six consecutive donors quickly became senescent. Stable urine primary cell cultures could not be obtained from the three remaining donors. Repeated attempts to reprogram epithelial cells were not successful. During parallel studies conducted for healthy donors, reprogramming success was achieved in six out of ten cases. These data may suggest serious limitations in the regeneration system of individuals with FQAD. Consequently, it indicates that therapy with autologous iPSc derivatives may face serious difficulties in their case, still, the first iPSc cell line from a person with FQAD was established.

WCK 1152, WCK 1153: Discovery and structure activity relationship for the treatment of resistant pneumococcal and staphylococcal respiratory infections

Novel antibacterial agents needed constantly to counter the ever emergent resistance development to commercially available drugs; one of the effective synthetic antibacterial classes is fluoroquinolone (FQ). This study includes structure activity relationship based design and synthesis of novel fluoroquinolone molecules active against resistant pathogens bearing mutations of DNA gyrase and/or topoisomerase IV which also express efflux pumps. Here, series of compounds were prepared by treating 1-cyclopropyl-6,7-difluoro-8-methoxy-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid as a core with various 4-substituted-3,3-dialkyl piperidines as side chains, through conventional synthetic approaches. Subsequently, antibacterial activities of these fluoroquinolones were examined against Streptococcus pneumoniae, SPN 5844 (Moxi resistant DNA gyrase and topo IV mutant) and SPN 706 (FQ efflux positive). The current manuscript covers >50 examples of fluoroquinolone NCEs, amongst 20 NCEs have shown MIC in the range of (0.4 to >6.25 μg/ml) for SPN 5844 and (0.1-12.5 μg/ml) for SPN 706 strains. During the course of this study; WCK 919, comprising two chiral isomers; WCK 1152 and WCK 1153 were emerged as lead among the different series synthesized. Advance studies suggested either WCK 1152 or WCK 1153 are the worthy candidates for further clinical developments for respiratory infections caused by resistant pneumococci and staphylococci. However, on the basis of in house preclinical work, WCK 1152 had been selected for phase-1 domestic clinical trials.

Antibiotics as immunomodulators: a potential pharmacologic approach for ARDS treatment

First described in the mid-1960s, acute respiratory distress syndrome (ARDS) is a life-threatening form of respiratory failure with an overall mortality rate of approximately 40%. Despite significant advances in the understanding and treatment of ARDS, no substantive pharmacologic therapy has proven to be beneficial, and current management continues to be primarily supportive. Beyond their antibacterial activity, several antibiotics such as macrolides and tetracyclines exert pleiotropic immunomodulatory effects that might be able to rectify the dysregulated inflammatory response present in patients with ARDS. This review aims to provide an overview of preclinical and clinical studies that describe the immunomodulatory effects of antibiotics in ARDS. Moreover, the underlying mechanisms of their immunomodulatory properties will be discussed. Further studies are necessary to investigate their full therapeutic potential and to identify ARDS phenotypes which are most likely to benefit from their immunomodulatory effects.

Epidemiology, Clinical Characteristics, and Risk Factors for Running-Related Injuries among South African Trail Runners

Trail running involves running on varying natural terrains, often including large elevation gains/losses. Trail running has a high risk of injury, and runners often participate in remote regions where medical support is challenging. The aim of this study was to determine the epidemiology, clinical characteristic, and associated injury risk factors among trail runners. A modified Oslo Sports Trauma Research Center Questionnaire for Health Problems (OSTRC-H) was used biweekly to collect running-related injury (RRI) and training history data prospectively, among 152 participants (males n = 120, females n = 32) over 30 weeks. We report an overall injury rate of 19.6 RRIs per 1000 h and an RRI mean prevalence of 12.3%. The leading anatomical site of RRIs was the lower limb (82.9%), affecting the knee (29.8%), shin/lower leg (18.0%), and the foot/toes (13.7%). A history of previous RRI in the past 12 months (p = 0.0032) and having a chronic disease (p = 0.0188) are independent risk factors for RRIs among trail runners. Two in three trail runners sustain an RRI mainly affecting the knee, shin/lower leg, and foot/toes. A history of previous RRI in the past 12 months and a having chronic disease is independently associated with RRI among trail runners. These results could be used to develop future RRI prevention strategies, combined with clinical knowledge and experience.

Biological Effects of Quinolones: A Family of Broad-Spectrum Antimicrobial Agents

Broad antibacterial spectrum, high oral bioavailability and excellent tissue penetration combined with safety and few, yet rare, unwanted effects, have made the quinolones class of antimicrobials one of the most used in inpatients and outpatients. Initially discovered during the search for improved chloroquine-derivative molecules with increased anti-malarial activity, today the quinolones, intended as antimicrobials, comprehend four generations that progressively have been extending antimicrobial spectrum and clinical use. The quinolone class of antimicrobials exerts its antimicrobial actions through inhibiting DNA gyrase and Topoisomerase IV that in turn inhibits synthesis of DNA and RNA. Good distribution through different tissues and organs to treat Gram-positive and Gram-negative bacteria have made quinolones a good choice to treat disease in both humans and animals. The extensive use of quinolones, in both human health and in the veterinary field, has induced a rise of resistance and menace with leaving the quinolones family ineffective to treat infections. This review revises the evolution of quinolones structures, biological activity, and the clinical importance of this evolving family. Next, updated information regarding the mechanism of antimicrobial activity is revised. The veterinary use of quinolones in animal productions is also considered for its environmental role in spreading resistance. Finally, considerations for the use of quinolones in human and veterinary medicine are discussed.

Ciprofloxacin and Levofloxacin as Potential Drugs in Genitourinary Cancer Treatment-The Effect of Dose-Response on 2D and 3D Cell Cultures

Introduction: Introducing new drugs for clinical application is a very difficult, long, drawn-out, and costly process, which is why drug repositioning is increasingly gaining in importance. The aim of this study was to analyze the cytotoxic properties of ciprofloxacin and levofloxacin on bladder and prostate cell lines in vitro. Methods: Bladder and prostate cancer cell lines together with their non-malignant counterparts were used in this study. In order to evaluate the cytotoxic effect of both drugs on tested cell lines, MTT assay, real-time cell growth analysis, apoptosis detection, cell cycle changes, molecular analysis, and 3D cultures were examined. Results: Both fluoroquinolones exhibited a toxic effect on all of the tested cell lines. In the case of non-malignant cell lines, the cytotoxic effect was weaker, which was especially pronounced in the bladder cell line. A comparison of both fluoroquinolones showed the advantage of ciprofloxacin (lower doses of drug caused a stronger cytotoxic effect). Both fluoroquinolones led to an increase in late apoptotic cells and an inhibition of cell cycle mainly in the S phase. Molecular analysis showed changes in BAX, BCL2, TP53, and CDKN1 expression in tested cell lines following incubation with ciprofloxacin and levofloxacin. The downregulation of topoisomerase II genes (TOP2A and TOP2B) was noticed. Three-dimensional (3D) cell culture analysis confirmed the higher cytotoxic effect of tested fluoroquinolone against cancer cell lines. Conclusions: Our results suggest that both ciprofloxacin and levofloxacin may have great potential, especially in the supportive therapy of bladder cancer treatment. Taking into account the low costs of such therapy, fluoroquinolones seem to be ideal candidates for repositioning into bladder cancer therapeutics.

Fluoroquinolones: Blessings Or Curses

Fluoroquinolones are one of the world's most valuable and popularly used categories of antimicrobial agents. This paper attempts to review the substantial progress of fluoroquinolones from their discovery to black box warning. Antibiotic drug choice will remain difficult in the presence of increasing resistance, but the introduction of fluoroquinolones has created a new and exciting era in antimicrobial treatment. These are a synthetic heterogeneous group of compounds used in both hospital and community practices to treat numerous severe infections. The era of quinolone antibiotics began with the serendipitous discovery of the quinolone prototype in 1962. The chronological development of fluoroquinolone reported that nalidixic acid was the first quinolone that gained popular choice for the treatment of urinary tract infection. The subsequent agents like levofloxacin, ofloxacin, norfloxacin, gatifloxacin, moxifloxacin, clinafloxacin, sparfloxacin, and ciprofloxacin were derived through side chain and nuclear manipulation from basic pharmacophore. The fluoroquinolone motifs have been found as a milestone, effective in certain infections that are respiratory tract infection, urinary tract infection, bone disorders, meningococcal and mycobacterial infections, sexually transmitted diseases, skin infections, etc. Fluoroquinolones are first entirely man-made antibiotics that exhibit antibacterial activity through the inhibition of topoisomerase II, topoisomerase IV and deoxyribonucleic acid gyrase, which is vital for chromosome replication and function. The post-marketing surveillance pointed out the favorable side effects associated with fluoroquinolones such as phototoxicity, QT interval prolongation and anaphylaxis. The discovery, development and clinical use of fluoroquinolone antibiotics in the last century contributed to a decline in morbidity and mortality rates.

Safety considerations with new antibacterial approaches for chronic bacterial prostatitis

Introduction: Chronic bacterial prostatitis (CBP) is a difficult-to-eradicate infection. Antibacterial therapy with currently licensed agents is hindered due to the increasing emergence of pathogen resistance worldwide and to frequent infection relapse. With limited treatment options, physicians are investigating new agents, which, however, may raise safety concerns.Areas covered: Antibacterial agents currently licensed for CBP were not considered. Available reports about the safety and efficacy of antibacterial agents that have been clinically tested or tentatively used to treat CBP in single cases were evaluated. This review also focused on agents targeting Gram-positive pathogens, whose prevalence as causative agents of CBP is increasing.Expert opinion: (i) Most antibacterial agents considered in this review have been administered off-label in the interest of patients, and their use requires particular caution. (ii) Reports describing the usage of many of the drugs reviewed here are still scant, and readers should be warned of the limited published evidence supporting therapy for CBP with these agents. (iii) As treatment must extend over several weeks, medium-term adverse events may occur and therapy should be individualized, taking into account the dosage and the potential toxicity of each specific antibiotic. Regarding dangerous drug-drug interactions, particular attention should be paid to the risk of ECG-QT-interval elongation.

Antibiotics: Conventional Therapy and Natural Compounds with Antibacterial Activity-A Pharmaco-Toxicological Screening

Antibiotics are considered as a cornerstone of modern medicine and their discovery offers the resolution to the infectious diseases problem. However, the excessive use of antibiotics worldwide has generated a critical public health issue and the bacterial resistance correlated with antibiotics inefficiency is still unsolved. Finding novel therapeutic approaches to overcome bacterial resistance is imperative, and natural compounds with antibacterial effects could be considered a promising option. The role played by antibiotics in tumorigenesis and their interrelation with the microbiota are still debatable and are far from being elucidated. Thus, the present manuscript offers a global perspective on antibiotics in terms of evolution from a historical perspective with an emphasis on the main classes of antibiotics and their adverse effects. It also highlights the connection between antibiotics and microbiota, focusing on the dual role played by antibiotics in tumorigenesis. In addition, using the natural compounds with antibacterial properties as potential alternatives for the classical antibiotic therapy is discussed.

Binocular Diplopia: A Possible Adverse Effect of Fluoroquinolone Therapy

The adverse effects of fluoroquinolones are yet to be fully elucidated. We present an interesting case of a 41-year-old male with binocular diplopia most likely induced by the use of a fluoroquinolone antibiotic.

Quinolones: Mechanism, Lethality and Their Contributions to Antibiotic Resistance

Fluoroquinolones (FQs) are arguably among the most successful antibiotics of recent times. They have enjoyed over 30 years of clinical usage and become essential tools in the armoury of clinical treatments. FQs target the bacterial enzymes DNA gyrase and DNA topoisomerase IV, where they stabilise a covalent enzyme-DNA complex in which the DNA is cleaved in both strands. This leads to cell death and turns out to be a very effective way of killing bacteria. However, resistance to FQs is increasingly problematic, and alternative compounds are urgently needed. Here, we review the mechanisms of action of FQs and discuss the potential pathways leading to cell death. We also discuss quinolone resistance and how quinolone treatment can lead to resistance to non-quinolone antibiotics.

N1-Benzofused Modification of Fluoroquinolones Reduces Activity Against Gram-Negative Bacteria

The fluoroquinolone class of antibiotics has a well-established structure-activity relationship (SAR) and a long history in the clinic, but the effect of electron-rich benzofused substituents at the N1 position remains poorly explored. Because groups at this position are part of the topoisomerase-DNA binding complex and form a hydrophobic interaction with the major groove of DNA, it was hypothesized that an electron-rich benzofused N1 substituent could enhance this interaction. Molecular modeling techniques were employed to evaluate the binding of certain N1-modified fluoroquinolones to DNA gyrase targets from both Staphylococcus aureus and Klebsiella pneumoniae species compared with ciprofloxacin and norfloxacin. Seven N1-modified fluoroquinolones were subsequently synthesized and tested against a panel of Gram-negative pathogens to determine minimum inhibitory concentration (MIC) values. Gram-negative outer membrane penetration was investigated using the membrane permeabilizer polymyxin B nonapeptide and compound efflux via resistance-nodulation-division-family efflux transporters was evaluated using the known efflux pump inhibitor phenylalanine-arginine β-naphthylamide. Additionally, the target inhibitory activity of representative compound 6e was determined in a cell-free environment. A correlation between N1 substituent hydrophobicity and activity was observed across the MIC panel, with compound activity decreasing with increased hydrophobicity. Those compounds with highest hydrophobicity were inactive because of poor solubility profiles whereas compounds with intermediate hydrophobicity were inactive because of impaired outer membrane penetration, and reduced inhibition of topoisomerase targets, the latter in contrast to modeling predictions. This study adds new information to the fluoroquinolone SAR and suggests limited utility of large hydrophobic substituents at the N1 position of fluoroquinolones.

Quinolones-Induced Musculoskeletal, Neurological, and Psychiatric ADRs: A Pharmacovigilance Study Based on Data From the Italian Spontaneous Reporting System

Background

The use of quinolones has been associated with the development of serious and persistent adverse drug reaction (ADR) mainly affecting muscles, joints and the nervous system. This risk has led the European Medicines Agency (EMA) to endorse some restrictions on the use of this class of antibiotic. Therefore, we performed a study to primary estimate the reporting probability of musculoskeletal, neurological, and psychiatric ADRs among quinolone generations using national data.

Methods

We retrieved Individual Case Safety Reports (ICSRs) with a quinolone as suspected drug among those reported through the Campania spontaneous reporting system from January 1^st, 2001 to April 30^th 2019. Moreover, we retrieved national aggregated safety data from the online public report system (RAM system) for the period from January 1^st, 2002 to March 31^st, 2019. Risk factors were classified as “age greater than 60 years,” “therapeutic indication,” “renal failure,” “organ transplantation,” “use of corticosteroid,” and “history of side effects”. Reporting odds ratio (ROR) was computed to evaluate the reporting probability of musculoskeletal, neurological, or psychiatric events among quinolones generations.

Results

A total of 87 ICSRs with a quinolone as suspected drug that reported at least one musculoskeletal, neurological, and psychiatric adverse event were identified in the Campania spontaneous reporting system. Forty-nine (56.3%) ICSRs reported risk factors (total risk factors 59). The most reported risk factor was “age greater than 60 years” (69.5%), followed by “therapeutic indication” (16.9%), “renal failure” (5.1%), “organ transplantation” (3.4%), “use of corticosteroid” (3.4%), and “history of side effects” (1.7%). Second-generation quinolones were associated with a lower reporting probability of musculoskeletal (ROR 0.70; 95% CI 0.63–0.79), neurological (ROR 0.81; 95% CI 0.73–0.90), and psychiatric (ROR 0.55; 95% CI 0.44–0.63) ADRs compared to the third generation of quinolones.

Conclusions

Our findings showed that third-generation quinolones were always associated with a higher reporting probability of musculoskeletal, neurological, and psychiatric ADRs compared to the second generation ones. Moreover, we described risk factors in more than half of our cases suggesting that the inappropriate use of quinolones is a phenomenon that may frequently predispose patients to the occurrence of these ADRs.

[Three keys to the appropriate choice of oral antibiotic treatment in the respiratory tract infections]

Exacerbation of chronic obstructive pulmonary disease and community-acquired pneumonia are the most frequent infections of the lower respiratory tract in daily clinical practice. Antibiotic selection is a crucial component in its treatment and, in most cases, it is performed empirically. Scientific societies make therapeutic recommendations based on scientific evidence and / or expert recommendations that are of great help to clinicians. Beta-lactams, fluoroquinolones and macrolides are the most commonly used drugs for oral administration. From a practical point of view, there are three keys to the appropriate choice of oral antibiotic treatment, which are the effectiveness, safety and the ecological impact on the patient's microbiota, including the development of resistance, which will be assessed in depth in this review.

Transferable Mechanisms of Quinolone Resistance from 1998 Onward

While the description of resistance to quinolones is almost as old as these antimicrobial agents themselves, transferable mechanisms of quinolone resistance (TMQR) remained absent from the scenario for more than 36 years, appearing first as sporadic events and afterward as epidemics. In 1998, the first TMQR was soundly described, that is, QnrA. The presence of QnrA was almost anecdotal for years, but in the middle of the first decade of the 21st century, there was an explosion of TMQR descriptions, which definitively changed the epidemiology of quinolone resistance. Currently, 3 different clinically relevant mechanisms of quinolone resistance are encoded within mobile elements: (i) target protection, which is mediated by 7 different families of Qnr (QnrA, QnrB, QnrC, QnrD, QnrE, QnrS, and QnrVC), which overall account for more than 100 recognized alleles; (ii) antibiotic efflux, which is mediated by 2 main transferable efflux pumps (QepA and OqxAB), which together account for more than 30 alleles, and a series of other efflux pumps (e.g., QacBIII), which at present have been sporadically described; and (iii) antibiotic modification, which is mediated by the enzymes AAC(6')Ib-cr, from which different alleles have been claimed, as well as CrpP, a newly described phosphorylase.

The safety of treatment options for acute bacterial skin and skin structure infections

INTRODUCTION

Acute bacterial skin and skin-structure infections (ABSSSI) may develop in both in-patients and out-patients, possibly with a severe clinical presentation. Since most phase 3 randomized clinical trials have shown non-inferiority in efficacy across different agents, considerations regarding their different safety profiles inevitably play a crucial role in the everyday choice about which of them should be employed for the treatment of ABSSSI.

AREAS COVERED

In this review, the authors discuss the safety profile of different treatment options for ABSSSI.

EXPERT OPINION

The spread of methicillin-resistant Staphylococcus aureus (MRSA) in the last decades has inevitably influenced the therapeutic approach to ABSSSI. Adequate knowledge of the peculiar toxicity profile of each drug active against MRSA is essential for guiding, monitoring and managing adverse events, in turn reducing any unfavorable impact of toxicity on patients' outcomes. In the next five years, potential toxicity will play a critical role in establishing the best available therapy for each specific patient, together with consideration regarding the possibility of avoiding hospitalization or allowing a switch from intravenous to oral therapy and early discharge.

Levofloxacin-induced tactile hallucination and acute anxiety reaction

Fluoroquinolones are the commonly used antimicrobials in the treatment of urinary tract infection, bacterial diarrhea, and infections of soft tissue, bone, and joints. They may cause adverse effects ranging from gastrointestinal disturbances, headache, insomnia, and cutaneous reactions. Their rare adverse effects include phototoxicity, cardiotoxicity, arthropathy, and tendinitis. Among the fluoroquinolones, levofloxacin has more propensity to cause the central nervous system adverse effects such as headache, tremor, insomnia, dizziness, convulsions, psychosis, auditory, and visual hallucinations. A case of acute sinusitis in a young male treated with levofloxacin presented with tactile hallucination and acute anxiety reaction is reported for its rarity of occurrence. According to the Naranjo causality scale, the association of tactile hallucination and acute anxiety is a probable adverse drug reaction due to levofloxacin.

Fluoroquinolone-related adverse events resulting in health service use and costs: A systematic review

Background and objectives

Adverse events (AEs) associated with the use of fluoroquinolone antimicrobials include Clostridium difficile associated diarrhea (CDAD), liver injury and seizures. Yet, the economic impact of these AEs is seldom acknowledged. The aim of this review was to identify health service use and subsequent costs associated with ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin and ofloxacin -related AEs.

Methods

A literature search covering Medline, SCOPUS, Cinahl, Web of Science and Cochrane Library was performed in April 2017. Two independent reviewers systematically extracted the data and assessed the quality of the included studies. All costs were converted to 2016 euro in order to improve comparability.

Results

Of the 5,687 references found in the literature search, 19 observational studies, of which five were case-controlled, fulfilled the inclusion criteria. Hospitalization was an AE-related health service use outcome in 17 studies. Length of hospital stay associated with AEs varied between <5 and 45 days. The estimated cost of an AE episode ranged between 140 and 18,252 €. CDAD was associated with the longest stays in hospital. Ten studies reported AE-related length of stays and five evaluated costs associated with AEs. Due to the lack of published literature, health service use and costs associated with many high-risk FQ-related AEs could not be evaluated.

Conclusions

Because of the wide clinical use of fluoroquinolones, in particular serious fluoroquinolone-related AEs can have substantial economic implications, in addition to imposing potentially devastating health complications for patients. Further measures are required to prevent and reduce health service use and costs associated with fluoroquinolone-related AEs. Equally, better-quality reporting and additional published data on health service use and costs associated with AEs are needed.

Moxifloxacin-Induced Visual Hallucinations, Alterations in Mood and Behavior, and Hyperglycemia

Visual hallucinations are sensory perceptions that occur without external stimuli. Moxifloxacin-induced visual hallucinations are very rarely reported (<0.1%). We describe a 66-year-old woman, without any known neuropsychiatric disorder or illicit drug abuse, who experienced complex visual hallucinations, mood, and behavioral alterations secondary to peroral 1 dose of moxifloxacin treatment that persisted for approximately 36 hours. In addition, a sudden increase in her blood glucose level was noted which also improved a few days after discontinuation of moxifloxacin treatment. Although very rare, it should be kept in mind that moxifloxacin may coincidentally induce neuropsychiatric adverse effects and hyperglycemia. Clinicians should be alert to recognize such uncommon offending adverse drug reactions.

Ozenoxacin: a review of preclinical and clinical efficacy

INTRODUCTION

Impetigo is the most common bacterial skin infection in children. Treatment is becoming complicated due to the development of antimicrobial resistance, especially in the main pathogen, Staphylococcus aureus. Ozenoxacin, a novel non-fluorinated topical quinolone antimicrobial, has demonstrated efficacy in impetigo. Areas covered: This article reviews the microbiology, pharmacodynamic and pharmacokinetic properties of ozenoxacin, and its clinical and microbiological efficacy in impetigo. Expert opinion: In an environment of increasing antimicrobial resistance and concurrent slowdown in antimicrobial development, the introduction of a new agent is a major event. Ozenoxacin is characterized by simultaneous affinity for DNA gyrase and topoisomerase IV, appears to be impervious to certain efflux pumps that confer bacterial resistance to other quinolones, shows low selection of resistant mutants, and has a mutant prevention concentration below its concentration in skin. These mechanisms protect ozenoxacin against development of resistance, while the absence of a fluorine atom in its structure confers a better safety profile versus fluoroquinolones. In vitro studies have demonstrated high potency of ozenoxacin against staphylococci and streptococci including resistant strains of S. aureus. Clinical trials of ozenoxacin in patients with impetigo reported high clinical and microbiological success rates. Preserving the activity and availability of ozenoxacin through antimicrobial stewardship is paramount.

Repositioning of fluoroquinolones from antibiotic to anti-cancer agents: An underestimated truth

Increasing development costs and higher failure rate in clinical trials has reduced the repertoire of newer drugs in the market for clinical use. The most appropriate approach to end the search for newer drugs is "Repositioning", as it requires less time and money to explore new indication of existing drug or failed drug. In the past, several drugs have been repositioned for different indication but the full potential remains unharnessed. With rise in cancer prevalence and treatment costs, it is imperative to search for newer drugs and the use of repositioning approach may help us. Fluoroquinolones has been used as antibiotics for over four decades now, but recent research highlighted their use as pharmacological compounds with multifaceted implication. Repositioning of fluoroquinolones into anti-cancer molecule seems to be a highly plausible option owing to their profound immunomodulatory, pro-apoptotic, anti-proliferative and anti-metastatic potential. The present review provides a comprehensive account of the recent and past explorations pertaining to the anti-cancer activity of fluoroquinolones and also discusses the various approaches that are being considered to remodel them for the treatment of cancer.

Studies on articular and general toxicity of orally administered ozenoxacin in juvenile rats and dogs

AIM

Ozenoxacin is a nonfluorinated quinolone antibacterial approved for topical treatment of impetigo. Because quinolones have known chondrotoxic effects in juvenile animals, the potential toxicity of ozenoxacin was assessed in preclinical studies.

MATERIALS & METHODS

Ozenoxacin or ofloxacin (300 mg/kg/day for 5 days, for each compound) was orally administered to juvenile rats, and oral ozenoxacin (10-100 mg/kg/day for 14 days) was administered to juvenile dogs.

RESULTS

In juvenile rats, ozenoxacin showed no chondrotoxicity, whereas ofloxacin produced typical quinolone-induced lesions in articular cartilage in three of ten rats. Oral ozenoxacin administration to juvenile dogs showed no chondrotoxicity or toxicologically relevant findings in selected target organs.

CONCLUSION

Ozenoxacin was generally well-tolerated in juvenile rats and dogs, with no evidence of quinolone-induced arthropathy.

Safety of Delafloxacin: Focus on Adverse Events of Special Interest

Background

Fluoroquinolones have been widely used for a variety of Gram-positive and Gram-negative infections, and by 2002 they had become the most commonly prescribed class of antibiotics for adults in the United States. With widespread use, the class has become associated with a range of adverse events. Delafloxacin is a fluoroquinolone approved in the United States for the treatment of adults with acute bacterial skin and skin structure infections (ABSSSIs). Delafloxacin is differentiated from other fluoroquinolones due to structural differences and in its activity against methicillin-resistant Staphylococcus aureus, including quinolone-resistant strains. This paper reviews the safety profile of delafloxacin across clinical studies with an emphasis on the incidence of adverse events of special interest that are associated with fluoroquinolones.

Methods

Data from 2 completed phase III studies of delafloxacin for the treatment of ABSSSIs were pooled and are the primary focus of this paper. Additional support from the full safety analysis set (30 completed phase I to phase III clinical studies) is included where applicable.

Results

Fewer patients in the pooled delafloxacin group had AESIs than in the comparator group (7.0% vs 9.2%, respectively). Delafloxacin had a low rate of discontinuations due to treatment-related adverse events (<1%). Serious adverse events occurred at similar rates in patients treated with delafloxacin vs comparators.

Conclusions

Serious adverse events occurred at similar rates in patients treated with delafloxacin vs nonquinolone comparators used to treat ABSSSIs.

Clinicaltrials.gov identifier

NCT01984684 and NCT01811732

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.

Adverse events of fluoroquinolones vs. other antimicrobials prescribed in primary care: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Fluoroquinolones (FQs) are second-line antimicrobial agents. Once the decision to prescribe an antimicrobial is made, the choice of antimicrobial should be based on both the benefits and adverse effects. This systematic review quantifies the occurrence of common adverse events (AEs) related to FQs in relation to any other antimicrobial for any indication in primary care.

METHODS

We searched randomized controlled trials from Embase, PubMed, Cochrane Central Register of Controlled Trials and CINHAL. FQs had to be administered orally, for any indication, to adults and in primary care. Data were extracted independently in standard forms in "Covidence". Pooled estimates of the intervention effects for AEs were determined by the Peto odds ratios (ORs) and 95% confidence intervals (CIs) in Revman.

RESULTS

In the 39 studies selected, the most commonly reported AEs were nausea, vomiting, diarrhoea, headache, dizziness, and rash. A meta-analysis of 28 studies reporting AEs showed central nervous system (CNS)-related AEs (OR 1.40 (1.12-1.75) P = 0.003, heterogeneity (I²) = 0%) and gastrointestinal (GI)-related AEs (OR 1.20 (1.06-1.36) P = 0.005, I² = 80%) were significantly associated with FQs compared with other antimicrobials. Compared with FQs, co-amoxiclav showed significantly more total AEs (OR 0.70 (0.54-0.90) P = 0.006, I² = 78%) and GI-related AEs (OR 0.69 (0.52-0.91) P = 0.008, I² = 94%). Withdrawal or discontinuation due to drug-related AEs was higher for FQs (OR 1.19 (1.00-1.42) P = 0.05, I² = 5%). Sensitivity analyses did not change these results.

CONCLUSION

FQs are associated with more CNS- and GI-related AEs compared with other types of antimicrobial. This information is relevant to support decision making in relation to antimicrobial prescribing.

Relationship Between Fluoroquinolone Structure and Neurotoxicity Revealed by Zebrafish Neurobehavior

Central nervous system side effects are one of the most frequently reported adverse reactions of fluoroquinolones (FQs). However, the mechanism is not fully understood. In this study, zebrafish ( Danio rerio) were used as a model system. We quantified neurobehavior by recording indicators with automated video-tracking and used liquid chromatography-tandem mass spectrometry to detect drug absorption in vivo. We studied embryotoxicity and effects on zebrafish locomotor activity of 17 typical FQs. In addition, we calculated the stable conformation of typical FQs in aqueous conditions. The relationships between structure, neurotoxicity, and embryotoxicity were analyzed. The results indicate: (1) The effects of FQs on zebrafish neurobehavior can be divided into four categories. Type I has no significant influence on locomotor activity. Type II suppresses locomotor activity. Type III inhibits at low concentration and stimulates at high concentration. Type IV stimulates and then suppresses (biphasic response). (2) Structural modifications of FQs can change toxicity properties in zebrafish. Cleavage of the C-7 piperazinyl structure decreases neurotoxicity but enhances embryotoxicity. The C-3 decarboxyl formation and 5-NH₂ derivatives might enhance embryotoxicity and neurotoxicity. (3) There are two toxic functional groups. The piperazinyl structure at position C-7 (toxic functional group I) can cause primary reactions which may be by the inhibition of γ-aminobutyric acid receptors, and the nucleus containing a carboxyl group at position 3 (toxic functional group II) might cause a reaction secondary to the effect of toxic functional group I and reverse its effects.

Antibiotic Therapy for Acute Watery Diarrhea and Dysentery

Diarrheal disease affects a large proportion of military personnel deployed to developing countries, resulting in decreased job performance and operational readiness. Travelers' diarrhea is self-limiting and generally resolves within 5 days; however, antibiotic treatment significantly reduces symptom severity and duration of illness. Presently, azithromycin is the preferred first-line antibiotic for the treatment of acute watery diarrhea (single dose 500 mg), as well as for febrile diarrhea and dysentery (single dose 1,000 mg). Levofloxacin and ciprofloxacin are also options for acute watery diarrhea (single dose 500 mg and 750 mg, respectively) and febrile diarrhea/dysentery in areas with high rates of Shigella (500 mg once for 3 days [once daily with levofloxacin and twice daily with ciprofloxacin]), but are becoming less effective because of increasing fluoroquinolone resistance, particularly among Campylobacter spp. Another alternate for acute watery diarrhea is rifaximin (200 mg 3 times per day for 3 days); however, it should not be used with invasive illness. Use of loperamide in combination with antibiotic treatment is also beneficial as it has been shown to further reduce gastrointestinal symptoms and duration of illness. Because of regional differences in the predominance of pathogens and resistance levels, choice of antibiotic should take travel destination into consideration.

Data-driven prediction of adverse drug reactions induced by drug-drug interactions

Background

The expanded use of multiple drugs has increased the occurrence of adverse drug reactions (ADRs) induced by drug-drug interactions (DDIs). However, such reactions are typically not observed in clinical drug-development studies because most of them focus on single-drug therapies. ADR reporting systems collect information on adverse health effects caused by both single drugs and DDIs. A major challenge is to unambiguously identify the effects caused by DDIs and to attribute them to specific drug interactions. A computational method that provides prospective predictions of potential DDI-induced ADRs will help to identify and mitigate these adverse health effects.

Method

We hypothesize that drug-protein interactions can be used as independent variables in predicting ADRs. We constructed drug pair-protein interaction profiles for ~800 drugs using drug-protein interaction information in the public domain. We then constructed statistical models to score drug pairs for their potential to induce ADRs based on drug pair-protein interaction profiles.

Results

We used extensive clinical database information to construct categorical prediction models for drug pairs that are likely to induce ADRs via synergistic DDIs and showed that model performance deteriorated only slightly, with a moderate amount of false positives and false negatives in the training samples, as evaluated by our cross-validation analysis. The cross validation calculations showed an average prediction accuracy of 89% across 1,096 ADR models that captured the deleterious effects of synergistic DDIs. Because the models rely on drug-protein interactions, we made predictions for pairwise combinations of 764 drugs that are currently on the market and for which drug-protein interaction information is available. These predictions are publicly accessible at http://avoid-db.bhsai.org. We used the predictive models to analyze broader aspects of DDI-induced ADRs, showing that ~10% of all combinations have the potential to induce ADRs via DDIs. This allowed us to identify potential DDI-induced ADRs not yet clinically reported. The ability of the models to quantify adverse effects between drug classes also suggests that we may be able to select drug combinations that minimize the risk of ADRs.

Conclusion

Almost all information on DDI-induced ADRs is generated after drug approval. This situation poses significant health risks for vulnerable patient populations with comorbidities. To help mitigate the risks, we developed a robust probabilistic approach to prospectively predict DDI-induced ADRs. Based on this approach, we developed prediction models for 1,096 ADRs and used them to predict the propensity of all pairwise combinations of nearly 800 drugs to be associated with these ADRs via DDIs. We made the predictions publicly available via internet access.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-017-0153-6) contains supplementary material, which is available to authorized users.

Moxifloxacin-induced acute psychosis: A case report with literature review

Third generation quinolones are extensively used to treat a variety of common bacterial infections. Due to their extensive use in clinical practice, an increase in neuropsychiatric events has been reported. We report the case of psychotic symptoms occurs after three doses of moxifloxacin in a healthy adult male with no underlying risk factors. After the discontinuation of moxifloxacin treatment, there was a complete resolution of patient's symptoms. The case draws attention to a rare side effect of a commonly use drug and alert the clinicians to be cautious in those patients that have a baseline risk factors which makes the patient more susceptible to such adverse drug effect.

Drug-induced photosensitivity: Photoallergic and phototoxic reactions

Drug-induced photosensitivity refers to the development of cutaneous disease due to the interaction between a given chemical agent and sunlight. Photosensitivity reactions can be classified as phototoxic or photoallergic. Sometimes, there is an overlap between these two patterns, making their distinction particularly difficult for the clinician. We review the drugs that have been implicated as photosensitizers, the involved mechanism, and their clinical presentations. The main topical agents that cause contact photosensitivity are the nonsteroidal antiinflammatory drugs, whereas the main systemic drugs inducing photosensitivity are antimicrobials, nonsteroidal antiinflammatory agents, and cardiovascular drugs. Drug-induced photosensitivity remains a common clinical problem and is often underdiagnosed.

Current and future directions in the treatment and prevention of drug-induced liver injury: a systematic review

While the pace of discovery of new agents, mechanisms and risk factors involved in drug-induced liver injury (DILI) remains brisk, advances in the treatment of acute DILI seems slow by comparison. In general, the key to treating suspected DILI is to stop using the drug prior to developing irreversible liver failure. However, predicting when to stop is an inexact science, and commonly used ALT monitoring is an ineffective strategy outside of clinical trials. The only specific antidote for acute DILI remains N-acetylcysteine (NAC) for acetaminophen poisoning, although NAC is proving to be beneficial in some cases of non-acetaminophen DILI in adults. Corticosteroids can be effective for DILI associated with autoimmune or systemic hypersensitivity features. Ursodeoxycholic acid, silymarin and glycyrrhizin have been used to treat DILI for decades, but success remains anecdotal. Bile acid washout regimens using cholestyramine appear to be more evidenced based, in particular for leflunomide toxicity. For drug-induced acute liver failure, the use of liver support systems is still investigational in the United States and emergency liver transplant remains limited by its availability. Primary prevention appears to be the key to avoiding DILI and the need for acute treatment. Pharmacogenomics, including human leukocyte antigen genotyping and the discovery of specific DILI biomarkers offers significant promise for the future. This article describes and summarizes the numerous and diverse treatment and prevention modalities that are currently available to manage DILI.

QT Prolongation and Oncology Drug Development

Many pharmaceutical agents interact with cardiac ion channels resulting in abnormal ventricular repolarization and prolongation of the QT interval. In rare circumstances, this has resulted in the development of the potentially life-threatening arrhythmia, torsades de pointes. It is recognized, however, that accurate measurement of the QT interval is challenging, and it is a poor predictor for the development of this arrhythmia. Nevertheless, QT interval monitoring is an essential part of pharmaceutical development, and significant increases in the QT interval may prevent a drug from gaining approval.

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.

Use of the respiratory fluoroquinolones for the outpatient management of community-acquired pneumonia

BACKGROUND

Approximately 4 million cases of community-acquired pneumonia (CAP) occur in the United States each year, with the majority treated on an outpatient basis. The first fluoroquinolones (eg, ciprofloxacin) were used with caution for respiratory tract infections due to limited in vitro activity against common gram-positive pathogens. With the availability of levofloxacin, followed by gatifloxacin and moxifloxacin hydrochloride, which exhibited increased activity against gram-positive organisms, the fluoroquinolones have become a practical choice for the treatment of CAP.

OBJECTIVE

The aim of this review was to compare the respiratory fluoroquinolones in the outpatient management of CAP.

METHODS

We conducted a search for English-language articles (key terms: fluoroquinolone, levofloxacin, gatifloxacin, moxifloxacin, and pneumonia; years: 1996-2004). Data from published literature were reviewed regarding clinical and microbiologic efficacy and tolerability; pharmacokinetic and pharmacodynamic properties; and drug costs of levofloxacin, gatifloxacin, and moxifloxacin.

RESULTS

The 3 fluoroquinolones reviewed showed comparable clinical and microbiologic efficacy for the treatment of CAP. In general, the fluoroquinolones were well tolerated, although some differences have been reported, including higher rates of gastrointestinal and other adverse events for gatifloxacin and moxifloxacin. Gatifloxacin and moxifloxacin exhibited greater in vitro potency than levofloxacin against Streptococcus pneumoniae. However, levofloxacin achieved a higher serum drug concentration than the other agents, allowing similar attainment of pharmacokinetic and pharmacodynamic targets required for effective treatment.

CONCLUSIONS

The respiratory fluoroquinolones provided appropriate first line treatment in select patients with CAP on the basis of their microbiologic and clinical efficacy and their safety profiles.