Antibiotic Use and Tendon Injury – Is there a link?

The diagnosis and management of tendon injuries have changed over the years.  For example, “tendinitis” isn’t quite as common as what we once thought.  Instead, tendons undergo cellular changes related to tissue degeneration, and inflammation is not a major component of most chronic tendon injuries. Given this, tendinopathy is now the more commonly used term. Tendinopathy refers to a tendon that is painful when being used. Usually, there are signs of disorganization at a cellular level, but the primary characteristic is pain.  We’ve also learned that tendons like to be used, so we try not to completely rest them. If they are rested, they deteriorate and become less capable, which as a result makes them more susceptible to injury. Tendons get injured when tissue load surpasses tissue capacity. We know that tendinopathy and degeneration of tendons are extremely common as we age, and quite often, these structural changes really don’t matter. They don’t necessarily make the tendon weaker and they don’t always become symptomatic.  Not impressed yet?  Perhaps you didn’t know about the link between certain antibiotics and tendinopathy!

Fluoroquinolone antibiotics and tendinopathy

Fluoroquinolone antibiotics are one type of antibiotics that treat a variety of conditions. Some of these include respiratory conditions, conditions causing prostatitis, skin soft tissue infections and sexually transmitted infections.  They are also frequently prescribed for traveller’s diarrhea.  Common names of these antibiotics include ciprofloxacin, levofloxacin, pefloxacin and norfloxacin. An interesting systematic review published in 2014 found 175 relevant papers pertaining to the association of fluoroquinolone antibiotics and tendinopathy.  After reviewing all the relevant literature, the authors concluded that this type of antibiotic can certainly play a role in tendon injury.  However, taking these antibiotics doesn’t necessarily mean you’re at risk of rupturing a tendon. It’s when we combine their use with certain variables that the risk becomes significant. They called these other variables “synergistic factors.”  Synergistic factors include advanced age, use of low dose corticosteroids (such as an asthma puffer), chronic renal conditions, exercise (loading of the tendon) and general cellular adiposity.  Less serious synergistic factors would include diabetes, rheumatic disease, gout and hyperparathyroidism. So what does all this mean?  It means if you combine some of the aforementioned synergistic variables along with these antibiotics you’re setting yourself up for a tendon injury.

Imagine a hypothetical patient named Bob.  Bob is in his late forties.  Given this fact alone (his age), he likely has some underlying degeneration in his achilles tendon.  It isn’t painful and never has been. He has asthma for which he takes regular corticosteroid medication (puffers). He’s been inactive for a while but recently decided to start running. Incidentally, Bob got a rash on his arm that required antibiotics. He was prescribed Fluoroquinoline.  After being on the medication for a week, Bob ruptured his achilles tendon while trying to get a personal best on his 5km run.

There’s a lot to consider here. Bob likely had a degenerated tendon because of his age. He’s never done any strengthening to make it strong. Bob then overloaded the tendon beyond its capacity when he tried to run a personal best.  Bob was taking medication for his asthma and was on fluoroquinolone antibiotics. Statistically speaking, Bob’s achilles tendon was bound to rupture.  In this case, Bob might want to discuss with his family doctor an alternate antibiotic that isn’t in the fluoroquinolone family. Although rest isn’t usually great for tendons, Bob might need to consider more rest than we would normally recommend given the presence of this synergistic combination still in his system.  Eccentric exercise, often prescribed for tendon injuries would likely be a bad idea in the early stages of his recovery. A more cautious approach to his rehabilitation in the early phases is warranted.  Perhaps a strategy of relative rest for a short time followed by isometric loading is a better path instead of diving right into the popular strategy of eccentric loading.

Research

Perhaps I’m a nerd, but I really found this systematic review to offer some useful clinical information.  Here are some other interesting tidbits from this research…

  • The effect of fluoroquinolones on tendons can occur within hours of taking them.
  • Usually, if there will be an effect, it occurs around 6 days after starting the medication.
  • Symptoms/effects can persist for 6 months after cessation of the medication.
  • Achilles tendon is by far the most common tendon that this association is seen with. The achilles tendon is affected in 95% of cases of fluoroquinolone-related tendinopathy and rupture.
  • Compared with the use of other antibiotics, the use of fluoroquinolones carries a 3.8-fold increased risk of achilles tendinopathy.
  • This concept is not new. There are 175 research papers on this topic.
  • Combining fluoroquinolones and corticosteroids increases the risk of achilles rupture by 46 times when compared to someone who is on neither medication.

In short, if you’re prescribed antibiotics, double-check if they are Fluoroquinolones.  That still might be the most appropriate medication for you, so discuss it with your family doctor. This link between Fluoroquinolones and tendon injury may be more pertinent for active people of advanced age (loading a pre-existing tendinopathy) who are taking these medications and have some of the listed synergistic factors present. In addition, this may be information relevant to chiropractors or physiotherapists who are assisting you with your rehabilitation as a more conservative approach could be indicated in the early phases as opposed to other tendon injuries not related to Fluoroquinolones.

If you have a tendon injury and need assistance, please give our clinic a call.  We can help!  Common tendons that are injured include the achilles tendon, tendons associated with the plantar fascia, gluteal tendons, elbow tendons as seen with tennis elbow and golfers elbow, patellar tendons and rotator cuff tendons.  The treatment and load management of injured tendons is best done under the guidance of a professional who is knowledgeable about tendon injury and newer concepts associated with tendon rehabilitation.

By: Dr. Kevin McIntyre B.Kin, DC
Clinic Director – Burlington Sports Therapy

References

Lewis T, Cook J.  Fluoroquinolones and tendinopathy: a guide for athletes and sports clinicians and a systematic review of the literature.  J Athl Train 2014 May-Jun; 49(3):422-427.

Cook JL, Khan KM, Maffulli N, Purdam C. Overuse tendinosis not tendonitis: part 2: applying the new approach to patellar tendinopathy. The Physician and SportsMedicine 2000; 28(6).

Khan KM, Cook JL, Kannus P, Maffulli N, Bonar SF. Time to abandon the “tendonitis” myth. British Medical Journal 2002; 324: 626-627.

Khan KM, Cook JL, Taunton, J, Bonar F. Overuse tendinosis, not tendonitis: part 1: a new paradigm for a difficult clinical problem. The Physician and Sports Medicine 2000; 28 (5).

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