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These antibiotics can cause Achilles tendinitis and tendon rupture

Updated: Jun 1, 2022

Fluoroquinolone antibiotics are highly effective broad‐spectrum antibiotics that work for a wide variety of infections, but they can have a very negative effect on tendons. As a result the current guidelines suggest that Fluoroquinolone antibiotics should only be used in cases where all other treatment options have failed. It can cause both Achilles tendinitis and spontaneous Achilles tendon rupture in previously fit and active individuals. Important: this does not mean that ALL antibiotics are bad for tendons – only Fluoroquinolones.

These antibiotics can cause Achilles Tendinitis and Tendon Rupture

The Achilles tendon seems to be the most commonly affected by the use of these antibiotics, but it can involve any of the tendons in your body. It affects both young and old people with reported ages ranging between 18 to 91 years.

In this article:

  • Different types of Fluoroquinolones

  • Why do Fluoroquinolones cause tendon injury?

  • What is a safe dose?

  • Risk factors

  • What if I have to take these antibiotics?

Here's a video I did about this:

Different types of Fluoroquinolones

All of these types of fluoroquinolones have been shown to affect tendons:

  • ciprofloxacin (Cipro)

  • enoxacin

  • fleroxacin

  • gatifloxacin

  • levofloxacin

  • moxifloxacin

  • norfloxacin

  • ofloxacin

  • pefloxacin

Why do Fluoroquinolones cause tendon injury?

In short, fluoroquinolones interfere with your collagen turnover in your tendons. All the cells in our bodies, including our collagen fibres in our tendons, are constantly renewing – old ones are being absorbed and replaced by new healthy ones. These antibiotics seem to stop the body from forming new collagen fibres.

You may notice that I'm using the word tendinitis in this article rather than tendinopathy and that's because fluoroquinolones do seem to cause quite a dramatic inflammatory reaction in the tendons with reports of red, hot and swollen Achilles tendons. There are also reports of sudden rupture without any preceding symptoms.

It’s been shown to also affect cartilage and bones, especially in juvenile weight-bearing joints and should not be used in children.

Consult a physio online for an assessment of your Achilles injury and a tailored treatment plan. Follow the link to learn more.

What is a safe dose?

The research has shown that, where tendons are concerned, there’s no such thing as a “safe” dose of fluoroquinolones. For some patients symptoms of tendon pain has been reported to start as soon as 2 hours after the first dose while other patients were only affected 6 months after they had already stopped taking the medication.

Risk factors

Anyone using or who have used fluoroquinolones in the last 6 months are at risk of Achilles tendinitis and/or Achilles tendon rupture, but there are some factors that can increase your chances of developing these injuries.

Tendon loading sports: When we do tendon loading sports (like running and jumping) our Achilles tendons develops micro-trauma. This is normal. After every exercise session the body repairs this micro-trauma and as a result your tendon becomes stronger. Unfortunately fluoroquinolones interfere with this process and stop your tendon from forming new collagen fibres to repair the damage. You’re at a high risk of developing Achilles tendinitis/tendinopathy or tearing your Achilles tendon if you do tendon loading sports within 6 months of using fluoroquinolone antibiotics.

Corticosteroid use: We know from the research that long term use of corticosteroid drugs (inhalers or tablets) can predispose patients to tendon injury. In one study, patients prescribed both fluoroquinolones and corticosteroids had a 46-fold greater risk of Achilles tendon rupture than those taking neither medication.

Older age: As we get older our tendons take longer to recover and produce new cells so it is no surprise that older people are more likely to develop Achilles tendon injuries when prescribed fluoroquinolones.

Diabetes mellitus, rheumatic disease, gout and hyperparathyroidism are all conditions that have been shown to be risk factors for developing Achilles tendinopathy and they seem to further increase your risk of developing Achilles injuries when you use fluoroquinolones.

What if I have to take these antibiotics?

If you have to take these antibiotics, I would advise that you keep your running volume and other tendon loading activities (jumping & walking) down and rather add in activities like swimming and cycling. You may also benefit from taking supplements that can help with tendon health.

Let me know if you have any questions. You can also consult us online via video call for an assessment of your Achilles injury and a tailored treatment plan.

Best wishes


About the Author:

Maryke Louw is a chartered physiotherapist and holds an MSc in Sports Injury Management. You can follow her on LinkedIn, Facebook, Twitter or Instagram.


  1. Khaliq Y, Zhanel GG. Fluoroquinolone-Associated Tendinopathy: A Critical Review of the Literature. Clinical Infectious Diseases 2003;36(11):1404-10. doi: 10.1086/375078

  2. Lang TR, Cook J, Rio E, et al. What tendon pathology is seen on imaging in people who have taken fluoroquinolones? A systematic review. Fundamental & Clinical Pharmacology 2017;31(1):4-16. doi: 10.1111/fcp.12228

  3. Lewis T, Cook J. Fluoroquinolones and Tendinopathy: A Guide for Athletes and Sports Clinicians and a Systematic Review of the Literature. Journal of Athletic Training 2014;49(3):422-27. doi: 10.4085/1062-6050-49.2.09

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