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

Anti-cancer therapeutic agents and carpal tunnel syndrome: Clinical, electrodiagnostic, and ultrasound findings in seven patients

INTRODUCTION

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and rarely develops after drug therapy. This study describes the clinical, electrodiagnostic (EDX), and ultrasound (US) findings in seven patients who experienced CTS due to anti-cancer therapeutic agents.

METHODS

All patients underwent EDX testing, and four patients had an US study.

RESULTS

CTS occurred in four patients with aromatase inhibitors, two with immune checkpoint inhibitors, and one with a selective estrogen receptor modulator. The mean duration between initiation of the anti-cancer therapeutic agents and symptom onset was 6 weeks (range: 2-12 weeks). Decreased digit sensation was noted in all patients; wasting and weakness of the abductor pollicis brevis (APB) was observed in three (42.8%) patients. The compound muscle action potentials (CMAP) of the APB and sensory nerve action potentials of the second or third digit could not be recorded in two (28.5%) and four (57.1%) patients, respectively. The needle EMG detected fibrillations and positive sharp waves in the APB in two patients. The motor unit potentials of the APB were decreased with large polyphasics in three (42.8%) patients. Of the four patients who underwent US testing, all had increased cross-sectional area of the median nerve at the carpal tunnel inlet, three (75%) had thenar muscle atrophy, and two (50%) had a loss of fascicular pattern. Three (42.8%) patients underwent a CTR.

CONCLUSIONS

Physicians should be cognizant of the relationship between anti-cancer therapeutic agents and CTS. EDX studies and US play important roles in the diagnostic assessment of such patients.

Fluoroquinolone antibiotics and adverse events

Fluoroquinolones are broad-spectrum antibiotics with good oral bioavailability. They are used for the treatment of a wide variety of infections, but there are restrictions on prescribing these drugs.

Epidemiological studies have reported an increased risk of rare adverse effects. These include tendinopathy and tendon rupture, peripheral neuropathy and aortic aneurysm.

Safe prescribing of fluroquinolones requires recognition of patients with risk factors for toxicity. Prompt drug discontinuation is recommended in the event of an adverse reaction.

Practising antimicrobial stewardship by prescribing fluoroquinolones only when alternative drugs are unavailable is also key to limiting adverse events and antibiotic resistance.

Association of US Food and Drug Administration Removal of Indications for Use of Oral Quinolones With Prescribing Trends

IMPORTANCE

In May 2016, due to concerns of the risks outweighing the benefits, the US Food and Drug Administration (FDA) removed systemic quinolones' indications for acute, uncomplicated urinary tract infection (uUTI), acute sinusitis (AS), and acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). How the change influenced oral quinolone use is unknown.

OBJECTIVE

To assess the association of oral quinolone safety warnings and indication restrictions with use.

DESIGN, SETTING, AND PARTICIPANTS

This interrupted time series (January 2015-November 2018) analysis of the monthly prevalence of oral quinolone-treated infection episodes used a national sample of privately insured patients in outpatient care from the IBM MarketScan Database and included adults with antibiotic treatment of new uUTI, AS, or AE-COPD episodes, excluding patients with conditions that complicate infections, previous hospitalization, or other infections.

EXPOSURES

Time before and after May 2016 when the FDA mandated label changes.

MAIN OUTCOMES AND MEASURES

Monthly oral quinolone use prevalence by each condition before and after the label changes, overall and stratified by prescriber specialty.

RESULTS

In January 2015, quinolone prevalence among antibiotic-treated uUTI episodes (n = 652 235) was 41.6% (95% CI, 40.6%-42.5%); AS (n = 1 742 248) was 8.3% (95% CI, 7.9%-8.6%), and AE-COPD (n = 22 817) was 31.9% (95% CI, 30.3%-33.4%). Before the label changes, trends in monthly quinolone prevalence were nearly flat. The month of the label changes we noted an immediate reduction for uUTI (-7.2%; 95% CI, -8.6% to -5.8%); and to a lesser extent for AS (-1.2%; 95% CI, -1.5% to -0.9%) and AE-COPD (-2.6%; 95% CI, -4.1% to -1.1%), and continued monthly declines thereafter. Falsification tests confirmed an immediate decrease after the label change of quinolone use for uUTI but more obscured effects for AS and AE-COPD. Treatment shifted mostly to first-line (eg, nitrofurantoin in uUTI, amoxicillin in AS, macrolides in AE-COPD) and other second-line agents but use of not recommended antibiotics also increased (eg, tetracyclines in AE-COPD). Prescribing preferences varied, but significant reductions were seen across all prescriber specialties. At the end of the study period, quinolone was used for 19.2% of treated uUTIs, 2.9% of treated AS, and 14.6% of treated AE-COPD episodes.

CONCLUSIONS AND RELEVANCE

Label changes and their announcements was associated with an immediate reduction in oral quinolone use for uUTI and to a lesser extent for AS and AE-COPD. Quinolones continued to contribute a considerable proportion of treatments for uUTI and AE-COPD episodes at the end of the study period, pointing to opportunities for further improvement.

Association Between Peripheral Neuropathy and Exposure to Oral Fluoroquinolone or Amoxicillin-Clavulanate Therapy

Importance

Peripheral neuropathy has been associated with systemic fluoroquinolone exposure, but risk has been poorly quantified.

Objective

To calculate relative and absolute risk estimates for the association of fluoroquinolone exposure with peripheral neuropathy and to examine how risk may be affected by timing of fluoroquinolone exposure and by other risk factors.

Design, Setting, and Participants

This nested case-control study used anonymized data from all patients routinely registered with general practices in The Health Improvement Network database, a large primary care population database in the United Kingdom, from January 1, 1999, to December 31, 2015. Data analyses were conducted January 8, 2018. The cohort consisted of 1 338 900 adults issued 1 or more prescriptions of fluoroquinolone (34.3%) or amoxicillin-clavulanate (65.7%) antibiotics. Adults with incident peripheral neuropathy were matched (on age, sex, general practice, and calendar time) with up to 4 controls by using incidence density sampling selected from a cohort prescribed oral fluoroquinolone or amoxicillin-clavulanate antibiotics. Incidence rate ratios of peripheral neuropathy were calculated for fluoroquinolone and for amoxicillin-clavulanate exposure and compared with nonexposure among patients without diabetes, with sensitivity analyses testing the consistency of the results. Population mean-adjusted rate differences were then estimated, including the number needed to harm for various durations of fluoroquinolone therapy.

Exposures

Current and cumulative exposure to oral fluoroquinolone or amoxicillin-clavulanate antibiotics.

Main Outcomes and Measures

Incident peripheral neuropathy cases recorded in electronic medical records.

Results

In total, 5357 patients with incident peripheral neuropathy (mean [SD] age, 65.6 [14.7] years; 2809 women [52.4%]) were matched to 17 285 controls (mean [SD] age, 64.4 [15.2] years; 9485 women [54.9%]) without diabetes. Current oral fluoroquinolone exposure was associated with an increased relative incidence of peripheral neuropathy compared with nonexposure (adjusted incident rate ratio, 1.47; 95% CI, 1.13-1.92). Risk increased by approximately 3% for each additional day of current fluoroquinolone exposure and persisted for up to 180 days following exposure. No significant increased risk was observed with oral amoxicillin-clavulanate exposure. The absolute risk with current oral fluoroquinolone exposure was 2.4 (95% CI, 1.8-3.1) per 10 000 patients per year of current use. The number needed to harm for a 10-day course was 152 083 patients (95% CI, 117 742-202 778) and was greatest among men and among patients older than 60 years.

Conclusions and Relevance

The results of the present study suggested that oral fluoroquinolone therapy was associated with an increased risk of incident peripheral neuropathy that may depend on the timing of the exposure and the cumulative dose. Health care professionals should consider these potential risks when prescribing fluoroquinolone antibiotics.

Oral fluoroquinolones and risk of fibromyalgia

The Food and Drug Administration (FDA) has recently included a black box warning on fibromyalgia-like symptoms with fluoroquinolones (FQs) but no large epidemiologic study is to date available. We undertook a case-control study using a random sample of 9 053 240 subjects obtained from the PharMetrics Plus health claims database in the United States. Cases received at least two fibromyalgia diagnoses coded by a rheumatologist matched to ten randomly selected controls. After identifying 5148 cases of fibromyalgia and 51 480 controls, the adjusted rate ratio (RR) of fibromyalgia for use of any fluoroquinolones, amoxicillin and azithromycin were 1.63 (95% CI: 1.41-1.87), 1.64 (95% CI: 1.46-1.85) and 1.68 (95% CI, 1.49-1.89), respectively. The adjusted RR for any use of FQ compared to any use of amoxicillin or azithromycin was 0.99 (95% CI: 0.83-1.18) and azithromycin is 0.97 (95%CI: 0.82-1.16), respectively. The risk of fibromyalgia with FQs is similar to that with amoxicillin and azithromycin.

Fluoroquinolone Restriction as an Effective Antimicrobial Stewardship Intervention

PURPOSE OF REVIEW

Fluoroquinolones are a commonly prescribed antibiotic class that has come under scrutiny in recent years due to mounting evidence of association between adverse drug events, C. difficile infection and isolation of antibiotic-resistant bacteria.

RECENT FINDINGS

Inpatient antimicrobial stewardship (AMS) programs have a toolbox of potential interventions to curb inappropriate antibiotic use, prevent antibiotic-associated adverse drug events, and avoid unnecessary costs of care. Fluoroquinolone restriction policies in the acute care setting have demonstrated beneficial effects, including decreased rates of C. difficile infection and ESBL-producing Enterobacteriaceae. However, a simple blanket restriction policy may "squeeze the antibiotic balloon" and will likely be insufficient if not implemented in conjunction with other AMS interventions. There is a growing body of evidence to support formulary restriction of fluoroquinolones in the acute care setting to decrease rates of C. difficile infection and development of ESBL-producing organisms. Data on how to best implement these restrictions or how to implement outside of acute care settings is limited.