A Prospective Randomized Pilot Study on the Efficacy of a Dietary Supplementation Regimen of Vitamin E and Selenium for the Prevention of Fluoroquinolone-Induced Tendinopathy

Background: Fluoroquinolone-induced tendinopathy is a clinically significant adverse effect associated with this class of antibiotics, particularly affecting the Achilles tendon. Despite its growing recognition, the precise pathophysiological mechanisms remain incompletely understood, with hypotheses referencing increased matrix metalloproteinase activity, collagen degradation, and oxidative stress. Methods: This prospective randomized pilot study evaluates the potential protective effectiveness of vitamin E and selenium supplementation in mitigating fluoroquinolone-induced tendinopathy. The study was conducted on 25 patients receiving 500 mg/day levofloxacin antibiotherapy, randomly divided into a control group and an experimental group-vitamin E (400 IU/day) and selenium (200 µg/day), oral supplementation for 28 days. Clinical assessment of the pain level through the VAS score and of functionality through the VISA-A score was performed, alongside ultrasound imaging of the Achilles tendon. To assess potential toxicity and ensure adherence to the supplementation protocol, serial biochemical analyses of serum vitamin E and selenium were performed at predetermined intervals. Results: A significant improvement was observed in pain scores (p = 0.0120) and functional outcomes (p = 0.0340) when comparing the control and experimental groups at the three-month follow-up. Ultrasound analysis revealed reduced tendon thickness and neovascularization, supporting structural recovery. Although the incidence of tendinopathy was lower in the interventional group (13.3% vs. 40%), statistical significance was not reached, possibly due to the small sample size. Conclusions: These findings suggest that antioxidant supplementation with vitamin E and selenium may provide a protective effect against fluoroquinolone-induced tendinopathy, warranting further investigation in larger randomized clinical trials.