*This is not intended to be medical advice. This article is simply educational. Please talk to your doctor about the best treatment plan for you.

Antibiotics are prescribed to treat bacterial infections (which can be respiratory infections, skin infections, UTI, STI, etc.). One certain class of antibiotics, fluoroquinolones, increases the risk of both tendon ruptures and tendinopathies (a broad term for tendon conditions causing pain, inflammation, and dysfunction).1-2 However, fluoroquinolones are still commonly prescribed. Some examples of fluoroquinolones are ciprofloxacin (Cipro), levofloxacin (Levaquin), gemifloxacin, moxifloxacin, and ofloxacin.3-4 You can ask your doctor for the generic name of the medication rather than the brand name, and if it ends in “-floxacin,” it is almost certainly a fluoroquinolone.
As a lifter or athlete, you put more stress on your tendons than the average person; therefore, this should be a consideration when your doctor is choosing the most appropriate antibiotic to prescribe. However, most doctors are not used to thinking about a patient’s sporting activities while choosing medications, so you may need to advocate for yourself. I suggest that if you are ever prescribed an antibiotic, you ask the doctor if it is a fluoroquinolone. If they say yes, explain that, “I do (insert sport/activity) and therefore I am concerned about the potential tendon rupture risk associated with fluoroquinolones. Are there any other suitable antibiotics that would be an effective alternative?”
Fluoroquinolones and Tendinopathy: A Guide for Athletes and Sports Clinicians and a Systematic Review of the Literature (Lewis & Cook, 2014) recommends the following guidelines for fluoroquinolone use in athletes: “Athletes should avoid the use of fluoroquinolone antibiotics if an alternative is available. Oral or injected corticosteroids should not be administered at the same time as fluoroquinolones, athletes and their athletic trainers should be aware of the potential risks of these drugs, and close monitoring is suggested for at least 6 months after cessation of fluoroquinolone use.”
Even when talking about the general population and not specifically athletes, in 2016 the FDA advised healthcare providers that fluoroquinolones should not be used for uncomplicated infections due to their possible serious side effects and that fluoroquinolones “should be reserved for those who do not have alternative treatment options.”4
Some important background information for you to understand as a patient is that all antibiotics are not interchangeable. They have different mechanisms of action, so they won’t treat everything. For example, some antibiotics work by inhibiting bacterial cell wall construction. However, if the bacteria causing your infection doesn’t have a cell wall (for example, mycoplasma), then that type antibiotic would have no effect on treating your infection. There are many factors that go into decisions about what antibiotic is suitable for specific situations, such as the spectrum of activity, tissue penetration, bioavailability, half-life, and potential for antibiotic resistance. Therefore, there may be some cases where it is necessary for your doctor to prescribe a fluoroquinolone, and you should ALWAYS take the antibiotic that your doctor advises. I am simply recommending that you start a discussion around what physical activities you engage in and ask your doctor if there are suitable alternative antibiotics to fluoroquinolones.
For example, I was recently sick as dog water with pneumonia. I was prescribed a fluoroquinolone to treat it. I explained that I was worried about the risk of tendon rupture because I lift weights at an elite level, and the doctor agreed it was a good choice to switch to a different antibiotic instead.
One other thing to be aware of as a lifter or athlete is that taking corticosteroids along with fluoroquinolones resulted in a 46-fold increase in tendon rupture.1 So in the event that the doctor deems a fluoroquinolone necessary, if they also prescribe a corticosteroid, ask if that is absolutely necessary or not. Often corticosteroids are prescribed to reduce inflammation and make the patient feel better, but are not actually necessary to treat the root cause of the infection.
Now, this is not talking about anabolic steroids, the type that can be used for performance enhancement. Corticosteroids are very different. There is not yet research on anabolic steroid use with fluoroquinolones to see if that increases tendon rupture risk. However, anabolic steroid users are already at a higher risk than non-users of tendon rupture.5 So one might speculate that combining fluoroquinolones and anabolic steroids could put you at even greater risk than just one or the other, but again, we don’t currently have any studies on it. Proceed with caution if you are on anabolic steroids and have to take a fluoroquinolone.
There are other associated risk factors that may further increase your risk of tendon rupture or tendinopathy when combined with taking fluoroquinolones. These are older age (specifically defined in the research as >60 years old), renal failure, diabetes, history of tendon rupture, and concurrent corticosteroid use (as discussed above).1 Therefore, if you meet some of these other criteria and you must take fluoroquinolones, then you should be especially cautious since you are at an even greater risk.
According to The Risk of Fluoroquinolone-induced Tendinopathy and Tendon Rupture (Kim, 2010), taking fluoroquinolones increases your risk of tendinopathies 1.7-fold, your risk of tendon rupture 1.3-fold, and your risk of an Achilles tendon rupture specifically 4.1-fold. That risk can also increases if you combine it with an associated risk factor. For example, in those over 60 years old, there’s a 2.7-fold increase in tendon rupture. The most concerning associated risk factor is concurrent corticosteroid use, which resulted in a staggering 46-fold increase in tendon rupture.1
If you do have to take a fluoroquinolone because a doctor deemed it the best option for your situation despite your athletic activities, here are a few things to consider. First off, you want to be even more cautious during your return to sport/training after recovering from your infection than you would be if you hadn’t had a fluoroquinolone, especially if you have associated risk factors. I would recommend that you seek a well-educated coach or trainer to advise your training plan to further reduce your risk.
While the Achilles tendon is most commonly affected (89.8% of cases), other tendons have also been reported.1 The impact of fluoroquinolones and the risk of tendon issues isn’t limited to the Achilles; it is likely that this is just the most common location because it is loaded significantly by bodyweight during activities of daily living like walking. Therefore, in lifters or athletes, there should be attention to any other tendons loaded significantly in the activities they’re performing rather than focusing solely on the Achilles.
Another thing to be aware of is the duration of how long you may be at an elevated risk. You will be at an elevated risk even after the fluoroquinolone is discontinued. Up to 50% of cases of tendinopathies were after the fluoroquinolone was discontinued. The median onset of tendinopathy was 6 days after starting a fluoroquinolone, and 85% of cases were within first month after taking them; however, you could be at an elevated risk for up to 6 months or longer.1
In conclusion, fluoroquinolones seem to increase risk of tendon rupture and tendinopathies.1-2 If you are an athlete, it is recommended that you discuss with your doctor and see if there are any suitable alternative antibiotics for your infection.2,4 If not and you have to take a fluoroquinolone, discuss with your doctor to try and avoid taking it alongside a corticosteroid.2 Be extra cautious with your return to physical activity after your infection resolves. While the return to sport phase is likely the most dangerous period, since you are physically deconditioned and returning to activity, you will continue to be at some elevated risk for up to 6 months or more after discontinuing the drug.2 During this extended time period, continue to be cautious and consider having a well-educated coach, rehab specialist, or trainer guide your training plan to help reduce the risk.
Always take the drugs that your doctor advises – I am simply encouraging you to start the discussion with your doctor that fluoroquinolones may not be the best fit for your situation if you engage in vigorous physical activity due to the increased risk to tendons (especially when combined with corticosteroids). However, there will be times when fluoroquinolones are necessary and you should still take them as prescribed. Just exercise caution afterwards.
References:
1. Kim G. K. (2010). The Risk of Fluoroquinolone-induced Tendinopathy and Tendon Rupture: What Does The Clinician Need To Know? The Journal of Clinical and Aesthetic Dermatology, 3(4), 49–54.
2. Lewis, T., & Cook, J. (2014). Fluoroquinolones and Tendinopathy: A Guide for Athletes and Sports Clinicians and a Systematic Review of the Literature. Journal of Athletic Training, 49(3), 422–427. https://doi.org/10.4085/1062-6050-49.2.09
3. Pope, C. (2024, February 15). Quinolones and Fluoroquinolones. Drugs.com. https://www.drugs.com/drug-class/quinolones.html#:~:text=Some%20people%20use%20the%20words,be%20used%20from%20now%20on.
4. U.S. Food and Drug Administration. FDA Drug Safety Communication: FDA Updates Warnings for Oral and Injectable Fluoroquinolone Antibiotics Due to Disabling Side Effects. Silver Spring, MD: FDA; 2016. Available at: https://www.fda.gov/media/119537/download
5. Kanayama, G., DeLuca, J., Meehan, W. P., 3rd, Hudson, J. I., Isaacs, S., Baggish, A., Weiner, R., Micheli, L., & Pope, H. G., Jr (2015). Ruptured Tendons in Anabolic-Androgenic Steroid Users: A Cross-Sectional Cohort Study. The American Journal of Sports Medicine, 43(11), 2638–2644. https://doi.org/10.1177/0363546515602010
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