Pefloxacin-induced achilles tendon toxicity in rodents: biochemical changes in proteoglycan synthesis and oxidative damage to collagen

Systemic quinolone antibiotics in children: a review of the use and safety

Historically, healthcare providers have reluctantly used systemic quinolone antibiotics to treat infections in children when they have been used at all. Concerns regarding the oral or parenteral use of quinolones in children rose from research observations demonstrating cartilage and joint toxicity in juvenile animal models following the administration of this class of antibiotics to immature animals. A voluntary moratorium on the use of quinolone and fluoroquinolone antibiotics in children resulted in restricting their use to treat in infections in specific settings such as immunocompromised states due to chemotherapy, pseudomonas infections in cystic fibrosis patients, complicated urinary tract infections, and quinolone sensitive infectious disease where parenteral antibiotic administration is not available and quinolones were the only effective therapy. This article aims to review retrospective and prospective safety and efficacy data to provide a comprehensive summary of the systemic use of this class of antibiotics in children.

Fluoroquinolones and tendon disorders

Fluoroquinolones are the most potent oral antibiotics in clinical use today. Increasingly, these drugs are being prescribed for relatively benign infections and for new categories of patients, including paediatric patients. As their use becomes more frequent, so will the adverse events. This review focuses on a rare but debilitating adverse reaction, the fluoroquinolone-associated tendinopathy. Despite many published case reports and approximately 3500 cases reported to the World Health Organization Collaborating Centre for Drug Monitoring, little is known about the mechanisms behind this fluoroquinolone-specific toxicity. Data on chemical properties, mode of action, pharmacokinetic features, clinical presentation and risk factors in relation to tendon toxicity are discussed and the literature reviewed. As long as the musculoskeletal toxicity cannot be predicted by in vitro or in vivo models and this class of antibiotics is one of the most commonly linked to selection of resistant bacteria, a more prudent use of fluoroquinolones is warranted.

Missed Achilles tendon rupture due to oral levofloxacin: surgical treatment and result

We describe a case of a 60-year-old male patient who was treated with oral levofloxacin. The patient sustained a total subcutaneous rupture of the left Achilles tendon which was not diagnosed for at least 5 months. Surgical treatment was successful.

Rupture of multiple tendons after levofloxacin therapy

An 80-year-old man treated by levofloxacin developed multiple tendon ruptures. His symptoms resolved over 9 months after levofloxacin discontinuation. Nasal corticosteroid therapy, aging and chronic respiratory insufficiency were probably predisposing factors in this patient.

In vitro discrimination of fluoroquinolones toxicity on tendon cells: involvement of oxidative stress

Tendinopathy are classic side effects observed with fluoroquinolones antibiotics. A previously validated model based on a spontaneously immortalized rabbit tendon cell line (Teno cell line) was used to evaluate cellular responses to the fluoroquinolones pefloxacin (PEF), ofloxacin (OFX), levofloxacin (LVX), and ciprofloxacin (CIP), in various concentrations. Cell viability, redox status changes, reduced glutathione content, and reactive oxygen species production were assessed using neutral red, Alamar blue, monobromobimane and 2,7-dichlorofluorescindiacetate fluorescent probes, respectively. Living adherent tenocytes were analyzed using a cold light cytofluorometer adapted to 96-well microplates. All fluoroquinolones showed moderate cytotoxicity after 24 h and more severe, significant toxicity after 72 h on tendon cells. Moreover, two groups of fluoroquinolones may be differentiated: intrinsic toxicity for tendon cells was high with ciprofloxacin and pefloxacin [redox status decrease was 80 and 62% (*p < 0.05) for PEF and CIP at 1 mM for 72 h, respectively], but moderate with ofloxacin and levofloxacin LVX [redox status decrease was 30 and 22% (*p < 0.05) for OFX and LVX at 1 mM during 72 h, respectively]. Our model supports a role for early oxidative stress in the development of fluoroquinolone-induced tendinopathy. Moreover, our study indicates that intrinsic toxicity to tendon cells varies across fluoroquinolones. The Teno cell line may be a useful model for detecting and evaluating tendon toxicity of new fluoroquinolones and other drugs associated with tendinopathy.

Fluoroquinolones in the elderly: safety considerations

Fluoroquinolones such as ciprofloxacin, levofloxacin, moxifloxacin and gatifloxacin are widely used for the treatment of bacterial infections. Fluoroquinolone-induced adverse effects have not been reported to occur with increased frequency in the elderly, but large trials comparing the tolerability in aged and young individuals are not available. Renal function declines consistently with age and recommendations for dosage changes of renally eliminated fluoroquinolones (ofloxacin, levofloxacin, gatifloxacin) are related to changes in kidney function rather than to age per se. However, during routine clinical work, creatinine clearance data are usually not available; thus it seems more practical to recommend dosage adjustment for elderly individuals in whom low creatinine clearance values can be expected. Reactions of the gastrointestinal tract are the most often observed adverse effects during therapy with fluoroquinolones; however, compared with many other antibacterials, fluoroquinolones are less frequently associated with diarrhoea. Similarly, hypersensitivity reactions, as observed during therapy with penicillins and other beta-lactam agents, occur more rarely during fluoroquinolone therapy. Adverse reactions of the CNS are of particular concern for the elderly population. Elderly patients with impairments of the CNS (e.g. epilepsy, pronounced arteriosclerosis) should be treated with fluoroquinolones only under close supervision. Probably, many signs of possible adverse reactions such as confusion, weakness, loss of appetite, tremor or depression are often mistakenly attributed to old age and remain unreported. Fluoroquinolones can cause QT interval prolongation. Therefore, they should be avoided in patients with known prolongation of the QT interval, patients with uncorrected hypokalaemia or hypomagnesaemia and patients receiving class IA (e.g. quinidine, procainamide) or class III (e.g. amiodarone, sotalol) antiarrhythmic agents. Chondrotoxicity of fluoroquinolones, as observed in immature animals, has led to restricted use in paediatric patients, but there is no indication that similar effects could occur in joint cartilage of adults. Tendinitis and tendon ruptures have occurred in rare cases as late as several months after treatment with some fluoroquinolones. Chronic renal diseases, concomitant use of corticosteroids and age over 60 years have been recognised as risk factors for fluoroquinolone-induced tendon disorders. Overall, the widely used fluoroquinolones discussed in this review are generally well tolerated. Nevertheless, as with all drugs, their specific adverse effect profiles must be considered when they are chosen for treatment of bacterial infections. Because of physiological changes in renal function and in case of certain comorbidities, some special considerations are necessary when fluoroquinolones are used to treat elderly patients.

Fluoroquinolone-associated tendinopathy: a critical review of the literature

With the expanded use of fluoroquinolones for the treatment of community-acquired respiratory infections and reports of tendon injury linked to the use of these agents, we reviewed the literature to investigate the frequency and strength of this association. Ninety-eight case reports were available for review. The incidence of tendon injury associated with fluoroquinolone use is low in a healthy population but increases in patients who have renal dysfunction, who are undergoing hemodialysis, or who have received renal transplants. Pefloxacin and ciprofloxacin were most frequently implicated, but tendon injury was reported with most fluoroquinolones. The median duration of fluoroquinolone treatment before the onset of tendon injury was 8 days, although symptoms occurred as early as 2 hours after the first dose and as late as 6 months after treatment was stopped. Up to one-half of patients experienced tendon rupture, and almost one-third received long-term corticosteroid therapy. Tendon injury associated with fluoroquinolone use is significant, and risk factors such as renal disease or concurrent corticosteroid use must be considered when these agents are prescribed.

Clinical toxicological aspects of fluoroquinolones

Reactions of the gastrointestinal tract and the central nervous system are the most often observed adverse effects during therapy with fluoroquinolones. Pathogenesis of the neurotoxic effects of fluoroquinolones could be related to the activation of the NMDA receptor. Animal experiments as well as clinical experience show that the cardiotoxic potentials of sparfloxacin and grepafloxacin are higher than those of the other fluoroquinolones: they cause QT prolongation at rather low doses thus increasing the risk for severe arrhythmia (torsades de pointes). Phototoxicity has been described for all quinolones, but derivatives with a halogen atom at position 8 show the highest potential for such reactions (e.g. clinafloxacin). Chondrotoxicity of quinolones can affect the articular cartilage and the epiphyseal growth plate in immature animals; the use of these drugs in pediatrics should be restricted to carefully selected indications (such as the use of ciprofloxacin in cystic fibrosis). Tendinitis and tendon ruptures can also be induced by quinolones. Overall, quinolones are as well tolerated as most other anti-microbial agents. However, their specific toxic potentials have to be considered when they are chosen for treatment of bacterial infections.