A recent study, published in the Annals of Pharmacotherapy, has brought into sharp focus the risks associated with fluoroquinolone (FQ) antibiotics. A research team led by Virginia H. Fleming, PhD, an associate professor at the University of Georgia, did a full analysis.

“The risk of tendon injury is well known, but to our knowledge, the risk has not been evaluated comparatively between antibiotic options for a specific indication. Our study evaluates the risk of tendon injury in patients treated with fluoroquinolone versus non-fluoroquinolone antibiotics for community-acquired pneumonia,” Fleming explained.

They looked at how often tendon injuries occurred in people treated for community-acquired pneumonia (CAP). Specifically, they compared those treated with fluoroquinolone antibiotics versus those given non-fluoroquinolone antibiotics.

Fleming further explained: “We believe this approach is unique as it allows us to assess the risk of this potential side effect from a prescriber’s ‘use’ perspective when choosing between antibiotic options for a specific indication.”

Fluoroquinolones, including drugs like levofloxacin and moxifloxacin, are widely prescribed due to their effectiveness against a broad spectrum of bacteria. However, these drugs have been under scrutiny for their potential side effects, particularly tendon injuries. Previous studies have indicated an association but lacked a specific focus on CAP treatment. Fleming’s study aims to fill this gap by providing a more detailed and targeted analysis.

Discussing the findings, Fleming highlighted: “We found an increased risk of tendon injury within one month of therapy associated with the use of FQ antibiotics in patients treated for pneumonia in the outpatient setting.”

The research was structured as a retrospective, propensity score-weighted cohort analysis, utilising patient data from 2014–2020. It specifically targeted adults over 18 years who were treated for outpatient CAP. A critical aspect of the study was its exclusion of patients with prior tendon injuries to ensure a clearer view of the FQs’ impact.

Adding to this, Fleming noted: “Propensity score weighting was used to control for confounding factors including age, sex, previous, concurrent, or subsequent corticosteroid therapy, and the presence of concurrent chronic conditions.”

The study’s methodology stands out for its robustness. The researchers employed a propensity score weighting approach to balance out the cohorts based on various factors like age, sex, comorbidities, and concurrent medication use. This method significantly reduces potential biases that could skew the results, providing a more accurate assessment of the FQs’ risks.

Regarding the specific risks, Fleming pointed out: “Our results showed this risk to most frequently occur at the rotator cuff, shoulder, and patellar tendon rather than the Achilles tendon which has historically been the most often implicated.”

One of the most striking findings of the study was the 41.9% increased odds of tendon injury in patients treated with FQs, observed within one month of starting the therapy. This heightened risk was particularly noteworthy, as it was not seen over a longer period of six months. The injuries mostly happened to the rotator cuff, shoulder, and patellar tendons, which is different from previous research that mostly looked at Achilles tendon injuries.

Fleming underscored the study’s implications: “Our study adds support to the FDA recommendations to limit FQ use for uncomplicated infections when other options are available and suggests this also be a consideration for the treatment of pneumonia in the outpatient setting. We plan to conduct further evaluation of this comparative risk for a single indication in other types of infections – which will potentially represent a different patient demographic for analysis.”

The study provides detailed insights into the types and locations of tendon injuries. Contrary to the traditional focus on Achilles tendon injuries, this research highlights that other tendons, particularly in the shoulder and knee regions, are also at significant risk. This finding could lead to a reevaluation of how the medical community perceives the risk of tendon injuries associated with FQs.

The implications of these findings are significant for healthcare practitioners. The study’s conclusion that FQs should be prescribed with caution, especially for CAP, underscores the need for clinicians to consider alternative antibiotics with a lower risk profile for tendon injuries. This could lead to a shift in prescribing patterns, favouring safer alternatives where possible.

While previous studies have shed light on the tendon injury risks associated with FQs, Fleming’s research stands out for its specific focus on CAP treatment. This specificity not only provides clear guidance for this particular condition but also sets a precedent for future research to focus on specific indications when evaluating drug safety.

The study concludes with a strong recommendation for healthcare providers to be cognisant of the heightened risk of tendon injury within the first month of initiating FQ therapy for CAP. It calls for a more judicious use of these antibiotics, balancing their broad-spectrum efficacy with the potential risks they pose.