One of the most common and pronounced adverse drug reactions to fluoroquinolones is often manifested as severe joint, muscle and tendon pain. Ranging from a dull ache to a severe pain in various joints with the Achilles tendon most often times affected. Since 1982 it has been made known to the medical community that such events occur. It was not until 1996, fourteen years later, did anyone bother to address this issue. Public Citizen petitioned the FDA to add warnings and to issue "Dear Doctor" letters to physicians warning them of the danger presented. Of course the FDA only went so far as to add a couple sentences stating such damage was possible. The warning is buried within the monographs and hardly discernable. As a result more than twenty years later this is still considered by the medical community to be a "rare" phenomenon. If fact recently one physician had thought that he had discovered a "rare" side effect and had planned on writing a paper addressing it despite the fact that Casperian et al had done so twenty years earlier.

Research indicates a tremendous amount of multiple case reports of tendinitis (particularly Archilles tendinitis) and tendon rupture in patients receiving as little as ONE dose of fluoroquinolones, months and in some cases years after such therapy. Such tendinopathy can occur within a few days, weeks, or even months following a course of fluoroquinolone therapy. Tendon rupture can occur without a history of specific trauma. There are numerous theories as to how this occurs but the exact mechanics of such damage, twenty years later, still remains a mystery. Unlike other etiologies, bilateral tendinitis is common.

Fluoroquinolone induced tendinopathy is well described in France and, to a much lesser extent, by US rheumatologic and orthopedic journals, but there is scant information in primary care literature. Current research indicates that the primary care physician has not been exposed to the risk that he or she is subjecting their patients to. You can be assured that your primary care physician has no knowledge of this devastating adverse event. Fluoroquinolone induced tendinopathy is underreported, both in literature and to the FDA. Tendinopathy, arthralgia and myalgia have all been associated with fluoroquinolone therapy. Although the exact incident remains unknown due to the under reporting, together with the physicians failure to recognize, treat and report such events, some authors have estimated this to occur in 15 to 20 patients per 100,000 treated patients. No doubt that this number is far greater than this. From 1987 to 1997 the FDA had received 201 reported cases of tendon disorders. One has to seriously question how many other such events may have occurred that was either misdiagnosis or not reported by the physician or the patient.

The etiology of these lesions remains unknown. Numerous animal studies point to several factors that are suspected of causing such damage. The sudden onset of some tendinopathies points to direct toxicity. Few histological studies exist. Jorgensens et al proposed that such damage is vascular in nature as a result of insufficient blood supply. LeHuec et al indicates a reaction to a foreign body. A 1997 study by Movin et al revealed irregular collagen fiber arrangement. The concomitant use of corticosteroids and fluoroquinolones has long been recognized as a risk factor for developing tendinopathies of this nature. This has been presumably due to accelerated degeneration of collagen fibers. High load bearing tendons, such as the Achilles, quadriceps and rotator cuff tendons, are frequently described in the literature as being involved in tendinopathy.

Such tendinopathies may manifest as follows:

Grossly swollen tendon sheath

Acutely inflamed digital flexor tendon sheath

Trigger finger (the locking of one or several fingers)

DeQuervain’s tenosynovitis (disabling wrist pain)

Ganglia (carpal tunnel syndrome)

Tennis Elbow

Shoulder Pain

Hip Pain

Knee Pain

Posterior, Plantar and Forefoot Heel Pain

Achilles tendon pain

Rotary Cuff Pain