Tolerability of fluoroquinolone antibiotics. Past, present and future

Drugs with a negative impact on cognitive functions (part 3): antibacterial agents in patients with chronic kidney disease

The relationship between chronic kidney disease (CKD) and cognitive function has received increased attention in recent years. Antibacterial agents (ABs) represent a critical component of therapy regimens in patients with CKD due to increased susceptibility to infections. Following our reviewing work on the neurocognitive impact of long-term medications in patients with CKD, we propose to focus on AB-induced direct and indirect consequences on cognitive function. Patients with CKD are predisposed to adverse drug reactions (ADRs) due to altered drug pharmacokinetics, glomerular filtration decline, and the potential disruption of the blood-brain barrier. ABs have been identified as a major cause of ADRs in vulnerable patient populations. This review examines the direct neurotoxic effects of AB classes (e.g. beta-lactams, fluoroquinolones, aminoglycosides, and metronidazole) on the central nervous system (CNS) in patients with CKD. We will mainly focus on the acute effects on the CNS associated with AB since they are the most extensively studied effects in CKD patients. Moreover, the review describes the modulation of the gut microbiota by ABs, potentially influencing CNS symptoms. The intricate brain-gut-kidney axis emerges as a pivotal focus, revealing the interplay between microbiota alterations induced by ABs and CNS manifestations in patients with CKD. The prevalence of antibiotic-associated encephalopathy in patients with CKD undergoing intravenous AB therapy supports the use of therapeutic drug monitoring for ABs to reduce the number and seriousness of ADRs in this patient population. In conclusion, elucidating AB-induced cognitive effects in patients with CKD demands a comprehensive understanding and tailored therapeutic strategies that account for altered pharmacokinetics and the brain-gut-kidney axis.

Efflux Pump (QacA, QacB, and QacC) and β-Lactamase Inhibitors? An Evaluation of 1,8-Naphthyridines against Staphylococcus aureus Strains

The bacterial species Staphylococcus aureus presents a variety of resistance mechanisms, among which the expression of β-lactamases and efflux pumps stand out for providing a significant degree of resistance to clinically relevant antibiotics. The 1,8-naphthyridines are nitrogen heterocycles with a broad spectrum of biological activities and, as such, are promising research targets. However, the potential roles of these compounds on bacterial resistance management remain to be better investigated. Therefore, the present study evaluated the antibacterial activity of 1,8-naphthyridine sulfonamides, addressing their ability to act as inhibitors of β-lactamases and efflux pump (QacA/B and QacC) against the strains SA-K4414 and SA-K4100 of S. aureus. All substances were prepared at an initial concentration of 1024 μg/mL, and their minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. Subsequently, their effects on β-lactamase- and efflux pump-mediated antibiotic resistance was evaluated from the reduction of the MIC of ethidium bromide (EtBr) and β-lactam antibiotics, respectively. The 1,8-naphthyridines did not present direct antibacterial activity against the strains SA-K4414 and SA-K4100 of S. aureus. On the other hand, when associated with antibiotics against both strains, the compounds reduced the MIC of EtBr and β-lactam antibiotics, suggesting that they may act by inhibiting β-lactamases and efflux pumps such as QacC and QacA/B. However, further research is required to elucidate the molecular mechanisms underlying these observed effects.

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.

Design and synthesis of ciprofloxacin-sulfonamide hybrids to manipulate ciprofloxacin pharmacological qualities: Potency and side effects

Fluoroquinolones are a class of antibacterial agents used clinically to treat a wide array of bacterial infections. Although being potent, susceptibility to CNS side effects limits their use. It was observed that improvements in absorption, activity and side effects were achieved via modifications at the N atom of the C7 of the side chain. To meet the increasing demand for development of new antibacterial agents, nineteen novel ciprofloxacin-sulfonamide hybrid molecules were designed, synthesized and characterized by IR, ¹H NMR and ¹³C NMR as potential antibacterial agents with dual DNA gyrase/topoisomerase IV inhibitory activity. Most of the synthesized compounds showed significant antibacterial activity that was revealed by testing their inhibitory activity against DNA gyrase, DNA topoisomerase IV as well as their minimum inhibitory concentration against Staphylococcus aureus. Six ciprofloxacin-sulfonamide hybrids (3f, 5d, 7a, 7d, 7e and 9b) showed potent inhibitory activity against DNA topoisomerase IV, compared to ciprofloxacin (IC50: 0.55 μM), with IC50 range: 0.23-0.44 μM. DNA gyrase was also efficiently inhibited by five ciprofloxacin-sulfonamide hybrids (3f, 5d, 5e, 7a and 7d) with IC50 range: 0.43-1.1 μM (IC50 of ciprofloxacin: 0.83 μM). Compounds 3a and 3b showed a marked improvement in the antibacterial activity over ciprofloxacin against both Gram-positive and Gram-negative pathogens, namely, Staphylococcus aureus Newman and Escherichia coli ATCC8739, with MIC = 0.324 and 0.422 μM, respectively, that is 4.2-fold and 3.2-fold lower than ciprofloxacin (MIC = 1.359 μM) against the Gram-positive Staphylococcus aureus, and MIC = 0.025 and 0.013 μM, respectively, that is 10.2-fold and 19.6-fold lower than ciprofloxacin (MIC = 0.255 μM) against the Gram-negative Escherichia coli ATCC8739. Also, the most active compounds showed lower CNS and convulsive side effects compared to ciprofloxacin with a concomitant decrease in GABA expression.

The Crystalline Nephropathies

Crystalline nephropathies are a unique form of kidney disease characterized by the histologic finding of intrarenal crystal deposition. The intrinsic nature of some molecules and ions combined with a favorable tubular fluid physiology leads to crystal precipitation and deposition within the tubular lumens. Crystal deposition promotes kidney injury through tubular obstruction and both direct and indirect cytotoxicities. Further kidney injury develops from inflammation triggered by these crystals. From a clinical standpoint, the crystalline nephropathies are associated with abnormal urinalysis and urinary sediment findings, tubulopathies, acute kidney injury (AKI), and/or chronic kidney disease (CKD). Urine sediment examination is often helpful in alerting clinicians to the possibility of crystal-related kidney injury. The identification of crystals within the kidneys on biopsy by pathologists prompts clinicians to evaluate patients for medication-related kidney injury, dysproteinemia-related malignancies, and certain inherited disorders. This review will focus on the clinical and pathologic aspects of these 3 categories of crystalline nephropathies.

Prediction of potential drug interactions between repurposed COVID-19 and antitubercular drugs: an integrational approach of drug information software and computational techniques data

Introduction:

Tuberculosis is a major respiratory disease globally with a higher prevalence in Asian and African countries than rest of the world. With a larger population of tuberculosis patients anticipated to be co-infected with COVID-19 infection, an ongoing pandemic, identifying, preventing and managing drug–drug interactions is inevitable for maximizing patient benefits for the current repurposed COVID-19 and antitubercular drugs.

Methods:

We assessed the potential drug–drug interactions between repurposed COVID-19 drugs and antitubercular drugs using the drug interaction checker of IBM Micromedex®. Extensive computational studies were performed at a molecular level to validate and understand the drug–drug interactions found from the Micromedex drug interaction checker database at a molecular level. The integrated knowledge derived from Micromedex and computational data was collated and curated for predicting potential drug–drug interactions between repurposed COVID-19 and antitubercular drugs.

Results:

A total of 91 potential drug–drug interactions along with their severity and level of documentation were identified from Micromedex between repurposed COVID-19 drugs and antitubercular drugs. We identified 47 pharmacodynamic, 42 pharmacokinetic and 2 unknown DDIs. The majority of our molecular modelling results were in line with drug–drug interaction data obtained from the drug information software. QT prolongation was identified as the most common type of pharmacodynamic drug–drug interaction, whereas drug–drug interactions associated with cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp) inhibition and induction were identified as the frequent pharmacokinetic drug–drug interactions. The results suggest antitubercular drugs, particularly rifampin and second-line agents, warrant high alert and monitoring while prescribing with the repurposed COVID-19 drugs.

Conclusion:

Predicting these potential drug–drug interactions, particularly related to CYP3A4, P-gp and the human Ether-à-go-go-Related Gene proteins, could be used in clinical settings for screening and management of drug–drug interactions for delivering safer chemotherapeutic tuberculosis and COVID-19 care. The current study provides an initial propulsion for further well-designed pharmacokinetic-pharmacodynamic-based drug–drug interaction studies.

Plain Language Summary

Chemical synthesis, molecular docking and MepA efflux pump inhibitory effect by 1,8-naphthyridines sulfonamides

This study aimed to evaluate the antibacterial activity and to verify, in silico and in vitro, the inhibition of efflux mechanisms using a series of synthesized 1,8-naphthyridines sulfonamides against Staphylococcus aureus strains carrying MepA efflux pumps. The chemical synthesis occurred through the thermolysis of the Meldrum's acid adduct. The sulfonamide derivatives were obtained by the sulfonylation of 2-amino-5‑chloro-1,8-naphthyridine with commercial benzenesulfonyl chloride. Antibacterial activity was assessed by the broth microdilution test. Efflux pump inhibitory capacity was evaluated in silico by molecular docking and in vitro by analyzing synergistic effects on ciprofloxacin and ethidium bromide (EtBr) and by EtBr fluorescence emission assays. The following 1,8-naphthyridines were synthesized: 4-methyl-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10a); 2,5-dichloro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10b); 4-fluoro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10c); 2,3,4-trifluoro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10d); 3-trifluoromethyl-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10e); 4‑bromo-2,5-difluoro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10f). The 1,8-naphthyridines derivatives associated with sulfonamides did not show antibacterial activity. However, they showed a favorable pharmacokinetic profile with possible MepA efflux pump inhibitory action, demonstrated in molecular docking. In addition to the promising results in reducing the concentration of intracellular EtBr. 1,8-naphthyridines act as putative agents in the inhibitory action of the MepA efflux pump.

Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

The influence of the stable 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) nitroxide and its six C4-substituted derivatives, as well as two C3-substituted analogues of 2,2,5,5-tetramethylpyrrolidynyl-N-oxyl (PROXYL) nitroxide on the chosen fluoroquinolone antibiotics (marbofloxacin, ciprofloxacin, danofloxacin, norfloxacin, enrofloxacin, levofloxacin and ofloxacin), has been examined in aqueous solutions by UV absorption as well as steady-state and time-resolved fluorescence spectroscopies. The mechanism of fluorescence quenching has been specified and proved to be purely dynamic (collisional) for all the studied systems, which was additionally confirmed by temperature dependence experiments. Moreover, the selected quenching parameters—that is, Stern–Volmer quenching constants and bimolecular quenching rate constants—have been determined and explained. The possibility of electron transfer was ruled out, and the quenching was found to be diffusion-limited, being a result of the increase in non-radiative processes. Furthermore, as the chosen nitroxides affected the fluorescence of fluoroquinolone antibiotics in different ways, an influence of the structure and the type of substituents in the molecules of both fluoroquinolones and stable radicals on the quenching efficiency has been determined and discussed. Finally, the impact of the solvent’s polarity on the values of bimolecular quenching rate constants has been explained. The significance of the project comes from many applications of nitroxides in chemistry, biology and industry.

Photosensitivity induced by lomefloxacin versus other fluoroquinolones: A meta-analysis

Lomefloxacin may be more likely than other fluoroquinolones to cause photosensitivity. However, the rate of photosensitivity is variable and a meta-analysis has yet to be performed. The aim of this meta-analysis is to compare the rate of photosensitivity between outpatients who received lomefloxacin and those who received other fluoroquinolones. PubMed, EMBASE, Cochrane Library databases and trial registries were searched for randomized controlled trials (RCTs) of outpatients through June 12, 2019. The study outcome was the rate of photosensitivity based on the intention-to-treat principle, estimated by risk difference (RD) as the primary analysis and Peto odds ratio (Peto OR) as the secondary analysis, with 95% confidence intervals (CIs) using random-effects models. Four RCTs (total of 2295 patients) were included in this meta-analysis. A statistically higher risk of photosensitivity was found with lomefloxacin than with other fluoroquinolones (RD, 3.4%; 95% CI, 0.7%-6.2%; P-value = 0.013; I² = 10.9%). The odds of photosensitivity was also significantly higher with lomefloxacin (Peto OR, 5.81; 95% CI, 3.34 to 10.11; P-value <0.001; I² = 0%). This meta-analysis of RCTs found significantly higher photosensitivity with lomefloxacin compared to other fluoroquinolones. Considering this finding and given its lack of additional efficacy compared to other fluoroquinolones, lomefloxacin as a fluoroquinolone option should potentially be reconsidered.

Female Asthmatic Patients Have Higher Risk to Develop Gemifloxacin-Associated Skin Rash, Highlighting Unique Delayed Onset Characteristics

Gemifloxacin is a common oral antibiotic for lower respiratory tract infection worldwide. We noticed an uncommon delayed onset skin rash in patients who received Gemifloxacin. Therefore, we retrospectively reviewed all patients who received Gemifloxacin from 1 January 2011 to 31 May 2016 in a university-affiliated hospital in Taiwan. A total of 1358 patients were enrolled, of whom 36 (2.65%) had skin eruptions. The female patients had a significantly higher odds ratio (OR) 2.24 (95% confidence interval (CI) 1.11–4.53, p = 0.021) of having skin eruptions. A history of asthma was also a significant risk factor (OR 2.04, 95% CI = 1.01–4.14, p = 0.043). Female asthmatic patients had the highest risk of skin eruptions (10/129, 7.2%) with an adjusted OR up to 4.45 (95% CI = 1.81–10.93, p < 0.001) compared to male and non-asthmatic patients. Of note, up to 58.3% (21/36) of the patients experienced a skin rash after they had completed and stopped Gemifloxacin. The median onset time was on the second day (ranging one to five days) after completing treatment. We reported that female asthmatic patients have the highest risk of Gemifloxacin-associated skin eruptions in Asia and that they highlighted a unique delayed onset skin rash.

Nephrotoxicity of Ciprofloxacin: Five Cases and a Review of the Literature

Fluoroquinolones are usually well tolerated with a minimum of serious adverse effects; renal toxicity is uncommon. Apart from the renal side effects of ciprofloxacin, we aimed to highlight the renal impact of a ciprofloxacin overdose, and thus conducted a prospective study in the Department of Nephrology at La Rabta Hospital between 2010 and 2015. The cohort database was continually updated until the inclusion of five patients who were subjected to an overdose and who were initially admitted to the medical intensive care unit and then transferred to our department for acute renal failure (ARF) due to ciprofloxacin ingestion requiring urgent hemodialysis. All patients developed ARF after 12–36 h of ingestion. Renal ultrasound was normal in all cases. Twenty-four-hour proteinuria was present but not significant in one case, while microscopic hematuria was present in one case. Treatment consisted of supportive therapy and extrarenal purification by conventional intermittent hemodialysis. Four patients recovered normal renal function within 3 weeks and the remaining patient eventually had chronic kidney failure.

Leukocytoclastic Vasculitis with Systemic Involvement Associated with Ciprofloxacin Therapy: Case Report and Review of the Literature

A 71-year-old woman presented with constitutional signs and lower extremity palpable purpura after being prescribed a four-day course of 500 mg of ciprofloxacin two times daily for a gastrointestinal infection. She was admitted for inpatient treatment. During the third hospital day, she presented with an episode of abundant hematemesis while her skin lesions remained unchanged. Upper endoscopy revealed multiple lesions consistent with vasculitis and histological examination of the skin biopsy disclosed a leukocytoclastic vasculitis. The patient was successfully treated with prednisone following ciprofloxacin discontinuation. Complete resolution of the lesions on drug withdrawal strongly suggested drug toxicity, which was further supported by a score of 8 in the Naranjo Adverse Drug Reaction Probability Scale. Awareness that the development of skin and gastrointestinal lesions following administration of ciprofloxacin may be a manifestation of ciprofloxacin-induced vasculitis can help early detection, treatment, and lead to an overall good prognosis.

Imaging bacteria with radiolabelled quinolones, cephalosporins and siderophores for imaging infection: a systematic review

Bacterial infections are still one of the main causes of patient morbidity and mortality worldwide. Nowadays, many imaging techniques, like computed tomography or magnetic resonance imaging, are used to identify inflammatory processes, but, although they recognize anatomical modifications, they cannot easily distinguish bacterial infective foci from non bacterial infections. In nuclear medicine, many efforts have been made to develop specific radiopharmaceuticals to discriminate infection from sterile inflammation. Several compounds (antimicrobial peptides, leukocytes, cytokines, antibiotics…) have been radiolabelled and tested in vitro and in vivo, but none proved to be highly specific for bacteria. Indeed factors, including the number and strain of bacteria, the infection site, and the host condition may affect the specificity of tested radiopharmaceuticals. Ciprofloxacin has been proposed and intensively studied because of its easy radiolabelling method, broad spectrum, and low cost, but at the same time it presents some problems such as low stability or the risk of antibiotic resistance. Therefore, in the present review studies with ciprofloxacin and other radiolabelled antibiotics as possible substitutes of ciprofloxacin are reported. Among them we can distinguish different classes, such as cephalosporins, fluoroquinolones, inhibitors of nucleic acid synthesis, inhibitors of bacterial cell wall synthesis and inhibitors of protein synthesis; then also others, like siderophores or maltodextrin-based probes, have been discussed as bacterial infection imaging agents. A systematic analysis was performed to report the main characteristics and differences of each antibiotic to provide an overview about the state of the art of imaging infection with radiolabelled antibiotics.

Life-threatening metabolic coma caused by levofloxacin

Patients with diabetes mellitus are often susceptible to hypoglycemic episodes while on therapy. Most of these are attributed to inappropriate dosing of hypoglycemic agents, dietary indiscretion, or acute illness. Medications being used concomitantly should be reviewed closely when the etiology of hypoglycemia is unclear. A fifty-six-year-old woman with a history of diabetes mellitus (on metformin monotherapy) was found unresponsive at home. Her fingerstick glucose was 15 mg/dL for which she received 50% dextrose intravenously. The patient never had any previous documented hypoglycemic episodes. She had recently been diagnosed with pneumonia and was prescribed oral levofloxacin therapy. The patient had taken 4 doses of levofloxacin before the onset of hypoglycemia. These episodes recurred over the next 2 days needing close intensive care unit monitoring, dextrose infusion, and glucagon administration. Basic blood/urine investigations, cortisol and thyroid profile were normal except for low blood glucose and renal insufficiency (serum creatinine 1.4 mg/dL and creatinine clearance 42 mL/min). HbA1c was 6.8% (4.4%-6.4%), insulin 51.3 μU/mL (2.6-24.9 μU/mL), IGF-1 301 ng/mL (27-223 ng/mL), and C peptide 9.3 ng/mL (0.8-3.5 ng/mL). These levels were elevated but were deemed nondiagnostic because of fluctuating glucose values after glucagon administration. A blood screen for sulfonylureas and metaglinides was negative. A seventy-two-hour fast was performed to rule out hyperinsulinemic hypoglycemic syndromes; however, blood glucose values remained consistently above 120 mg/dL during this period. Thus, after exclusion of other causes, we utilized the adverse drug reaction probability scale and concluded that hypoglycemia was probably related to recent use of levofloxacin.

Acute pancreatitis secondary to ciprofloxacin therapy in patients with infectious colitis

BACKGROUND/AIMS

Ciprofloxacin is considered to be a safe and effective treatment for acute infectious colitis. However, this drug may cause drug-induced pancreatitis, albeit rarely.

METHODS

From March 2007 to February 2012, we studied 227 patients who were hospitalized for infectious colitis at St. Mary's Hospital. All of the patients received ciprofloxacin therapy for the treatment of infectious colitis. We observed a few cases of rare adverse events, including ciprofloxacin-induced acute pancreatitis diagnosed based on the Naranjo algorithm.

RESULTS

During ciprofloxacin therapy, seven of 227 patients (3.1%) developed rare pancreatitis as defined by the Naranjo algorithm; pancreatic enzyme activity was sporadically elevated with ciprofloxacin use. After ciprofloxacin administration, the average interval until the development of pancreatitis was 5.5 days (range, 4 to 7 days). On abdominal computed tomography, pancreatic swelling and homogenous enhancement was noted in three of seven patients. Complicating acute pancreatitis was gradually but completely resolved after cessation of ciprofloxacin administration. The mean recovery time was 11.3 days (range, 8 to 15 days).

CONCLUSIONS

We observed that ciprofloxacin-induced pancreatitis may occur with an incidence of approximately 3%. Ciprofloxacin-induced pancreatitis presents a short latency, suggesting an idiosyncratic hypersensitivity reaction. Practitioners should be aware that drug-induced pancreatitis can occur during ciprofloxacin therapy.

Efficacy and safety of levofloxacin in the context of other contemporary fluoroquinolones: a review

BACKGROUND

In recent years, fluoroquinolone research has focused on achieving several goals, including (1) enhanced potency against gram-positive cocci, notably Streptococcus pneumoniae, and anaerobes, while (2) maintaining potency against gram-negative pathogens, (3) optimizing pharmacokinetics and pharmacodynamics (PK/PD), and (4) minimizing potential adverse drug reactions through recognition and avoidance of structural configurations that have characterized earlier, reactive compounds.

OBJECTIVE

This review examines the efficacy and safety of fluoroquinolones and the specific clinical evidence regarding levofloxacin.

METHODS

Using published literature collected over time by the author, a review was conducted, focusing on the efficacy and safety profile of levofloxacin and other fluoroquinolones.

RESULTS

The newer fluoroquinolones have fulfilled many of the research goals described above. Levofloxacin has improved anti-gram-positive potency, PK/PD properties, a proven clinical trial record (particularly for communityacquired pneumonia [CAP]), and an excellent safety profile-in the context of the treatment of >250 million patients worldwide in the past decade. It is licensed for management of drug-resistant S pneumoniae infections in the United States and has gained widespread formulary acceptance and guideline inclusion. Studies assessing levofloxacin for CAP therapy show significant advantages over standard therapy, such as trends toward reduced IV therapy and length of hospitalization, reduced mortality, and significant associated cost reduction. In addition, levofloxacin has proved highly effective in acute exacerbations of chronic bronchitis (AECB), with excellent clinical and bacteriologic results, typical of the class, and significant advantages-in terms of clinical response, overall pathogen eradication, extension of the symptom-free period, and trends toward a reduction in the number of consultation visits and hospitalizations-over standard agents, such as the oral cephalosporins.

CONCLUSIONS

Levofloxacin offers a combination of documented efficacy and tolerability, and provides an important option for the treatment of bacterial infections, including CAP and AECB, compared with standard agents used in the management of lower respiratory tract infections.

Moxifloxacin safety: an analysis of 14 years of clinical data

Background

Moxifloxacin, a fluoroquinolone antibiotic, is used for the treatment of respiratory tract, pelvic inflammatory disease, skin, and intra-abdominal infections. Its safety profile is considered favorable in most reviews but has been challenged with respect to rare but potentially fatal toxicities (e.g. hepatic, cardiac, or skin reactions).

Objective

To analyze and compare the safety profile of moxifloxacin versus comparators in the entire clinical database of the manufacturer.

Setting

Data on the valid-for-safety population from phase II–IV actively controlled studies (performed between 1996 and 2010) were analyzed. Studies were either double blind (n = 22 369) or open label (n = 7635) and included patients with indications that have been approved in at least one country [acute bacterial sinusitis, acute exacerbation of chronic bronchitis, community-acquired pneumonia, uncomplicated pelvic inflammatory disease, complicated and uncomplicated skin and skin structure infections, and complicated intra-abdominal infections] (n = 27 824) and patients with other indications (n = 2180), using the recommended daily dose (400 mg) and route of administration (oral, intravenous/oral, intravenous only). The analysis included patients at risk (age ≥65 years, diabetes mellitus, renal impairment, hepatic impairment, cardiac disorders, or body mass index <18 kg/m²). Patients with known contraindications were excluded from enrollment by study protocol design, but any patient having entered a study, even if inappropriately, was included in the analysis.

Main Outcome Measure

Crude incidences and relative risk estimates (Mantel-Haenszel analysis) of patients with any adverse event (AE), adverse drug reaction (ADR), serious AE (SAE), serious ADR (SADR), treatment discontinuation due to an AE or ADR, and fatal outcomes related to an AE or ADR.

Results

Overall incidence rates of AEs were globally similar in the moxifloxacin and comparator groups. By filtering the data for differences in disfavor of moxifloxacin (i) at ≥2.5% for events with an incidence ≥2.5% or at ≥2-fold for events with an incidence <2.5% in one or both groups and (ii) affecting ≥10 patients in either group, we observed slightly more (i) AEs in double-blind intravenous-only and open-label oral studies, (ii) SAEs in double-blind intravenous-only studies, (iii) ADRs and SADRs in open-label oral studies, (iv) SADRs in open-label intravenous/oral studies, and (v) premature discontinuation due to AEs in open-label intravenous-only studies. The actual numbers of SADRs (in all studies) were small, with clinically relevant differences noted only in intravenous/oral studies and mainly driven by ‘gastrointestinal disorders’ (15 versus 7 patients) and ‘changes observed during investigations’ (23 versus 7 patients [asymptomatic QT prolongation: 11 versus 4 patients in double-blind studies]). Analysis by comparator (including another fluoroquinolone) did not reveal medically relevant differences, even in patients at risk. Incidence rates of hepatic disorders, tendon disorders, clinical surrogates of QT prolongation, serious cutaneous reactions, and Clostridium difficile-associated diarrhea were similar with moxifloxacin and comparators.

Conclusion

The safety of moxifloxacin is essentially comparable to that of standard therapies for patients receiving the currently registered dosage and for whom contraindications and precautions of use (as in the product label) are taken into account.

Levofloxacin-induced acute anxiety and insomnia

Fluoroquinolones can cause adverse neuropsychiatric side effects, which are more common in older age. We present three cases of levofloxacin-induced acute anxiety and insomnia in young adults. In all the cases, discontinuation of levofloxacin immediately lead to remission.

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.

Disturbance of cellular glucose transport by two prevalently used fluoroquinolone antibiotics ciprofloxacin and levofloxacin involves glucose transporter type 1

Dysglycemia and central nervous system (CNS) complications are the known adverse effects of fluoroquinolone antibiotics. Ciprofloxacin and levofloxacin are among the most prescribed antibiotics. In this study we demonstrate that ciprofloxacin and levofloxacin disturb glucose transport into HepG2 cells and such inhibition is associated with inhibited glucose transporter type 1 (GLUT1) function. When exposed to ciprofloxacin or levofloxacin at maximum plasma concentrations (C(max)) and 5x of C(max) concentrations, GLUT1 mRNA expression, cell surface GLUT1 protein expression and glucose uptake were significantly reduced. These findings imply that disturbed cellular glucose transport and GLUT1 function may underlie the dysglycemic and CNS effects of ciprofloxacin and levofloxacin.

Drug-induced crystal nephropathy: an update

BACKGROUND

Several medications that are insoluble in human urine are known to precipitate within the renal tubules. Intratubular precipitation of either exogenously administered medications or endogenous crystals (induced by certain drugs) can promote chronic and acute kidney injury, termed crystal nephropathy. Clinical settings that enhance the risk of drug or endogenous crystal precipitation within the kidney tubules include true or effective intravascular volume depletion, underlying kidney disease, and certain metabolic disturbances that promote changes in urinary pH favoring crystal precipitation.

OBJECTIVE

Identify and review previously described and recently recognized medications that cause crystal nephropathy.

METHOD

A literature review was performed, using PubMed, Ovid, and Google Scholar, focusing on drugs (sulfadiazine, acyclovir, indinavir, triamterene, methotrexate (MTX), orlistat, oral sodium phosphate preparation, ciprofloxacin) that cause crystal nephropathy.

RESULTS/CONCLUSION

Sulfadiazine, acyclovir, indinavir, triamterene, and MTX are known to cause crystal nephropathy. Recently, several medications, including orlistat, ciprofloxacin, and oral sodium phosphate solution, along with underlying risk factors have been described as causing crystal nephropathy.

Reactive oxygen species assay-based risk assessment of drug-induced phototoxicity: classification criteria and application to drug candidates

We have previously demonstrated that the phototoxic potential of chemicals could be partly predicted by the determination of reactive oxygen species (ROS) from photo-irradiated compounds. In this study, ROS assay strategy was applied to 39 marketed drugs and 210 drug candidates in order to establish provisional classification criteria for risk assessment of drug-induced phototoxicity. The photosensitizing properties of 39 model compounds consisting of phototoxic and non-phototoxic chemicals, as well as ca. 210 drug candidates including 11 chemical series were evaluated using ROS assay and the 3T3 neutral red uptake phototoxicity test (NRU PT). With respect to marketed drugs, most phototoxic drugs tended to cause type I and/or II photochemical reactions, resulting in generation of singlet oxygen and superoxide. There seemed to be a clear difference between phototoxic drugs and non-phototoxic compounds in their abilities to induce photochemical reactions. A plot analysis of ROS data on the marked drugs provided classification criteria to discriminate the photosensitizers from non-phototoxic substances. Of all drug candidates tested, 35.2% compounds were identified as phototoxic or likely phototoxic on the basis of the 3T3 NRU PT, and all ROS data for these phototoxic compounds were found to be over the threshold value. Furthermore, 46.3% of non-phototoxic drug candidates were found to be in the subthreshold region. These results verify the usefulness of the ROS assay for understanding the phototoxicity risk of pharmaceutical substances, and the ROS assay can be used for screening purposes in the drug discovery stage.

Analytical Studies on Photochemical Behavior of Phototoxic Substances; Effect of Detergent Additives on Singlet Oxygen Generation

PURPOSE

Monitoring of reactive oxygen species (ROS) generation from photoirradiated compounds would be effective for the prediction of the phototoxic potential. The aim of this investigation was to clarify the possible role of biomimetic vehicle systems on the photochemical properties of phototoxic compounds, focusing on the singlet oxygen generation.

MATERIALS AND METHODS

Nine phototoxic and one non-phototoxic compounds (200 microM), dissolved in Tween 20, sodium laurate, or sodium dodecyl sulfate (SDS) micellar solution, were exposed to UVA/B light (250 W/m2), and singlet oxygen generation was monitored by RNO bleaching methodology. Photochemical properties of photosensitizers were also evaluated by UV measurement, and the interaction of photosensitizers with surfactant micelles was assessed by Z-potential and NMR spectroscopic analyses.

RESULTS

All phototoxic compounds tended to generate singlet oxygen under light exposure in the all micellar solutions tested. There appeared to be some differences in photoreactivity of both cationic and anionic photosensitizers among the micelles tested, whereas ROS data on anthracene, dissolved in three micellar solutions, were found to be quite similar. Photosensitizers exhibited no significant changes in UV spectral patterns among the dissolving micellar solutions. Addition of cationic photosensitizer at the final concentration of 100 microM into 100 mM SDS solution resulted in the 20 mV increase of zeta potential and transition of NMR spectral pattern, which would reflect the electrostatic interaction with anionic micelles.

CONCLUSION

Based on the data obtained, the photoreactivity of photosensitizing molecules, especially cationic and anionic photosensitizers, strongly depends on the physicochemical properties of the microenvironment.

Cytotoxic effect of ciprofloxacin in primary culture of rat astrocytes and protection by Vitamin E

The aim of this study was to investigate the possible cytotoxic and oxidative stress inducing effects of ciprofloxacin (CPFX) on primary cultures of rat astrocytes. The cultured cells were incubated with various concentrations of CPFX (0.5-300mg/l), and cytotoxicity was determined by neutral red (NR) and MTT assays. Survival profile of cells was biphasic in NR assay: CPFX did not cause any alteration at any concentration for 7h, whereas < or =50mg/l concentrations induced significant cell proliferation in incubation periods of 24, 48, 72, and 96h. However, cell proliferation gradually decreased at higher concentrations, and 200 and 300mg/l of CPFX exposure was found to be significantly (p<0.05) cytotoxic at all time periods. With MTT assay, no alteration was noted for incubation period of 7h, as observed with NR assay. But, cell viability decreased with approximately > or =50mg/l CPFX exposure in all other time periods. Cell proliferation was only seen in 24h of incubation with 0.5 and 5mg/l CPFX. Vitamin E pretreatment of cell cultures were found to be providing complete protection against cytotoxicity of 300mg/l CPFX in 96h incubation when measured with both NR and MTT assays. The SOD pretreatment was partially protective with NR assay, but no protection was noted when measured with MTT. A significant enhancement of lipid peroxidation was observed with the cytotoxic concentration of the drug, but total glutathione content and catalase activity of cells did not change. The data obtained in this study suggest that, in accordance with our previous results with fibroblast cells, CPFX-induced cytotoxicity is related to oxidative stress. And the biphasic effect of CPFX possibly resulted from the complex dose-dependent relationships between reactive oxygen species, cell proliferation, and cell viability.

Analytical Studies on the Prediction of Photosensitive/Phototoxic Potential of Pharmaceutical Substances

PURPOSE

Phototoxic responses after administration of photosensitive pharmaceutics have been recognized as undesirable side effects, and predicting potential hazardous side effects is gaining importance as new drugs are introduced to the market. In this work, we characterize the photochemical/photobiological properties of model compounds to develop an effective screening method for the prediction of phototoxic/photosensitive potential.

METHODS

Twenty-one known photosensitive/phototoxic compounds and five weak/nonphototoxic compounds were subjected to ultraviolet (UV) spectral analyses and photochemical evaluation including the determination of produced reactive oxygen species (ROS) and photostability study. The photooxidation of linoleic acid was also monitored in the presence of tested compounds, guided on the formation of thiobarbituric acid reactive substances.

RESULTS

Most photosensitive/phototoxic drugs tested, even weak UV absorbers, at a concentration of 200 microM showed significant production of ROS under 18 h light exposure (30,000 lx). On the other hand, ROS generated from weak/nonphototoxic compounds, including strong UV absorber benzocaine, were low or negligible. Although exposure of quinine to light resulted in significant degradation (half-life, t1/2=6.4 h), it was dramatically attenuated by the addition of ROS scavengers, especially sodium azide (t1/2=122.6 h). Furthermore, concomitant exposure of photosensitive/phototoxic compounds (200 microM) and linoleic acid (1 mM) for 18 h led to the marked formation of lipoperoxide.

CONCLUSION

Results indicated that known photosensitive/phototoxic compounds tested have the ability to generate ROS under light exposure, and this photochemical reaction could be associated with their photoinstability and/or phototoxic responses. Based on these findings, determination of ROS, generated from photoirradiated compounds, may be an effective predictive model in recognizing their photosensitive/phototoxic potential.

Effets indésirables psychiatriques des fluoroquinolones : cas notifiés à la pharmacovigilance française

INTRODUCTION

Psychiatric adverse effects of fluoroquinolones are known for long, but can sometimes be missed. We analyse cases spontaneously reported to the French pharmacovigilance.

METHODS

Cases of psychiatric adverse effects with fluoroquinolones reported to the French pharmacovigilance system were analysed. The studied period was from January 1985 and June 2002. Data analysed included age, sex, adverse effect, fluoroquinolone, seriousness and evolution.

RESULTS

Five hundred ninety cases have been reported concerning 273 males and 316 females (sex unknown in 1 case). Mean age was 66 years (median: 70, range: 12-102). The most frequently reported psychiatric adverse effects were confusion (51%), hallucinations (27%), agitation (13%), delusion (12%), insomnia (8%), somnolence (4%) (several adverse effects could be associated in a single patient). Serious cases represented 21.7% (resulting in hospitalisation in most cases). Evolution was favourable in most cases (88.5%), and was unknown in 9.5% of cases.

CONCLUSION

The number of cases reported during this period is moderate, but under-reporting probably interferes. The eventuality of this kind of adverse effect with fluoroquinolones should be kept in mind. Dose should be adjusted to renal function, especially in older patients.

Glucose Homeostasis Abnormalities Associated with Use of Gatifloxacin

BACKGROUND

More than 20 published case reports have described an association between the use of gatifloxacin and hypoglycemia or hyperglycemia. We compare the rates of glucose homeostasis abnormality (GHA) adverse event reports (AERs) associated with the use of gatifloxacin and comparator quinolones.

METHODS

We obtained spontaneous AERs associated with the use of ciprofloxacin, gatifloxacin, levofloxacin, and moxifloxacin from the US Food and Drug Administration that were reported between November 1997 and September 2003. We removed duplicate and foreign cases. We used specific coding terms to identify GHA AERs. We calculated GHA AER rates, using either the total number of AERs or estimated retail prescriptions as denominators.

RESULTS

The use of ciprofloxacin, gatifloxacin, levofloxacin, and moxifloxacin was associated with 10,025 unique AERs in the United States, including 568 GHA AERs, 25 of which had fatality. Use of gatifloxacin was associated with 453 GHA AERs (80%) and 17 GHA AERs with fatality (68%). GHA AERs comprised 24% of all AERs associated with gatifloxacin, compared with ciprofloxacin (1.3%), levofloxacin (1.6%), and moxifloxacin (1.3%) (P<.0001 for each comparison). Use of gatifloxacin was associated with 477 GHA AERs per 10(7) retail prescriptions, compared with ciprofloxacin (4 GHA AERs), levofloxacin (11 GHA AERs), and moxifloxacin (39 GHA AERs) (P<.0001 for each comparison). Patients with GHA AERs were older and more likely to be receiving concomitant treatment for diabetes. Limitations of the study include the use of spontaneous adverse event reporting, which is incomplete and potentially biased. This analysis cannot be used alone to demonstrate causality.

CONCLUSIONS

Use of gatifloxacin is associated with a much higher rate of GHA AERs than are comparator quinolones. This analysis is consistent with the results of in vitro analyses, animal studies, human volunteer studies, case reports, and a large randomized trial. Alternatives to gatifloxacin should be used in patients with diabetes.

Treatment of Active Tuberculosis: Challenges and Prospects

This article reviews the basic principles of drug treatment of tuberculosis, individual pharmacologic agents, current treatment recommendations, and several special situations that clinicians are likely to encounter in medical practice.

Hypersensitivity reactions to fluoroquinolones

Fluoroquinolone antibiotics cause immediate and delayed hypersensitivity reactions, and may also affect internal organs and circulating blood cells. The underlying pathomechanisms are only partly understood. The extent of cross-reactivity among different quinolones depends on the type of clinical manifestation and its underlying mechanism. Despite recent advances, reliable diagnostic tests are still lacking. Recent studies have shown quinolone-specific IgE in vitro in more than 50% of patients with immediate-type reactions and a considerable cross-reactivity with related compounds. In maculopapular drug exanthems from ciprofloxacin, specific T-cell clones were identified, and cross-reactivity to related compounds was detected in approximately 50% of the clones. From re-exposure studies in patients with exanthems, cross-reactivity appears to be lower. Cellular tests such as lymphocyte transformation tests are currently not very useful. For prick and intradermal skin tests, widely divergent nonirritant test concentrations have been recommended. Desensitization may be possible in selected patients.

Les insuffisances rénales aiguës aux quinolones. Revue générale à propos d'une observation avec cristallisation liée à la ciprofloxacine

A 58 year-old woman developed an acute renal failure very quickly after ingestion of two 500 mg tablets of ciprofloxacin, without any other identifiable risk factor. Renal biopsy was performed. No sign of acute interstitial nephritis was observed but tubular lesions were found, accompanied by deposits of a brown-yellowish substance identified by infrared microscopy as a ciprofloxacin salt. The outcome was favourable. This observation gives the opportunity to remind the different forms of quinolone-induced renal injury and to discuss the possible ways for preventing renal side-effects related to the quinolone use.

A new respiratory fluoroquinolone, oral gemifloxacin: a safety profile in context

Gemifloxacin is a broad-spectrum quinolone antibacterial with enhanced potency against Gram-positive bacteria, including multi-drug resistant Streptococcus pneumoniae, and retained potency against Gram-negative bacilli and bacterial strains resistant to other antibiotics. It has proven particularly effective in respiratory and urinary tract infection. This review presents safety data from 6775 patients included in clinical trials, receiving either the recommended 320 mg once daily oral dose of gemifloxacin, or standard dose of other quinolones, macrolides or beta-lactams (n = 5248). Studies in healthy volunteer and special populations are also reported. Adverse experiences (AEs) were observed in 44.7% of gemifloxacin-treated patients and 47.5% of those who received comparator drugs. Mild gastro-intestinal adverse drug reactions (ADRs) (diarrhoea 5.1%, nausea 3.9%) predominated. Rash, usually maculo-papular and in no case proceeding to more severe eruptions, was observed in 3.6% of those receiving gemifloxacin. A higher incidence of rash (>20%) was observed in young women and was the subject of further study. Adverse drug reactions suspected or probably related to treatment occurred in 17.4% of patients receiving gemifloxacin and in 20% of those receiving comparator antibiotics. Diarrhoea and nausea were experienced by 3.6 and 2.7%, respectively, of gemifloxacin-treated patients (4.6 and 3.2% of comparators), rash by 2.8% (0.6% of comparators) and headache by 1.2% (1.5% of comparators). Gemifloxacin-related vomiting (0.9%), dizziness (0.8%) and taste perversion (0.3%) were uncommon. Treatment discontinuation followed one or more adverse drug reactions in 2.2% of gemifloxacin-treated patients (0.9% due to rash) and 2.1% of comparator-treated patients. A total of 63 deaths (33 receiving gemifloxacin) occurred in the trial population: none were considered related to treatment. A slight prolongation in QT interval (2.56 ms (S.D. +/-24.5)) was observed in gemifloxacin-treated patients: no cardiac arrhythmias were reported. There was a low incidence of liver function tests (LFTs) classified as of potential clinical concern: gemifloxacin (0.4-1.2%), comparators (0.2-1.3%). Serious adverse events (SAEs), occurring during but not necessarily related to therapy, occurred in 3.6% of gemifloxacin-treated patients (4.3% of comparators). SAEs related to treatment agents were rare (0.4% in each group) and included rash (0.1%) and elevated liver enzymes (<0.1%). Gemifloxacin was well tolerated by the elderly, those with renal or hepatic impairment and when co-administered with omeprazole, digoxin, theophylline, warfarin (with which there were no significant interactions) and Maalox. In conclusion, gemifloxacin 320 mg once daily demonstrated a favourable safety and tolerability profile similar to that of comparator antibiotics, including other quinolones.

[18F]Ciprofloxacin, a new positron emission tomography tracer for noninvasive assessment of the tissue distribution and pharmacokinetics of ciprofloxacin in humans

The biodistribution and pharmacokinetics of the fluorine-18-labeled fluoroquinolone antibiotic [(18)F]ciprofloxacin in tissue were studied noninvasively in humans by means of positron emission tomography (PET). Special attention was paid to characterizing the distribution of [(18)F]ciprofloxacin to select target tissues. Healthy volunteers (n = 12) were orally pretreated for 5 days with therapeutic doses of unlabeled ciprofloxacin. On day 6, subjects received a tracer dose (mean injected amount, 700 +/- 55 MBq, which contained about 0.6 mg of unlabeled ciprofloxacin) of [(18)F]ciprofloxacin as an intravenous bolus. Thereafter, PET imaging and venous blood sampling were initiated. Time-radioactivity curves were measured for liver, kidney, lung, heart, spleen, skeletal muscle, and brain tissues for up to 6 h after radiotracer administration. The first application of [(18)F]ciprofloxacin in humans has demonstrated the safety and utility of the newly developed radiotracer for pharmacokinetic PET imaging of the tissue ciprofloxacin distribution. Two different tissue compartments of radiotracer distribution could be identified. The first compartment including the kidney, heart, and spleen, from which the radiotracer was washed out relatively quickly (half-lives [t(1/2)s], 68, 57, and 106 min, respectively). The second compartment comprised liver, muscle, and lung tissue, which displayed prolonged radiotracer retention (t(1/2), >130 min). The highest concentrations of radioactivity were measured in the liver and kidney, the main organs of excretion (standardized uptake values [SUVs], 4.9 +/- 1.0 and 9.9 +/- 4.4, respectively). The brain radioactivity concentrations were very low (<1 kBq. g(-1)) and could therefore not be quantified. Transformation of SUVs into absolute concentrations (in micrograms per milliliter) allowed us to relate the concentrations at the target site to the susceptibilities of bacterial pathogens. In this way, the frequent use of ciprofloxacin for the treatment of a variety of infections could be corroborated.