Does Cefazolin (Ancef) cause Achilles tendinitis?

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Last updated: March 16, 2025View editorial policy

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From the Guidelines

Cefazolin (Ancef) is not typically associated with Achilles tendinitis, as it belongs to the cephalosporin class of antibiotics, which does not share the same side effect profile as fluoroquinolone antibiotics that are known to cause tendon problems. The provided evidence does not directly link Cefazolin to Achilles tendinitis, and the most recent study 1 focuses on the use of systemic and topical fluoroquinolones, as well as antibioprophylaxis in surgery and interventional medicine, without mentioning Cefazolin as a cause of tendon problems. Some key points to consider:

  • Fluoroquinolone antibiotics, such as ciprofloxacin or levofloxacin, are known to carry a risk of tendon problems, including Achilles tendinitis and rupture 1.
  • Cefazolin's common side effects include gastrointestinal issues, allergic reactions, and rarely blood disorders, but tendon problems are not among its recognized adverse effects.
  • The mechanism behind fluoroquinolone-induced tendinopathy involves direct toxicity to tendon tissue and disruption of collagen synthesis, whereas cephalosporins like Cefazolin work through different mechanisms that don't typically affect tendon structure.
  • If you're experiencing Achilles tendon pain while taking Cefazolin, it's more likely due to other factors such as physical activity, injury, or another underlying condition rather than the antibiotic itself. In summary, based on the available evidence, Cefazolin is not typically associated with Achilles tendinitis, and any tendon-related issues are more likely to be caused by other factors.

From the Research

Cefazolin and Achilles Tendinitis

  • There is no direct evidence that Cefazolin (Ancef) causes Achilles tendinitis in the provided studies.
  • However, the studies suggest that other antibiotics, including fluoroquinolones, have been associated with tendinopathy, tendonitis, and tendon rupture 2, 3, 4, 5, 6.
  • Cephalosporins, the class of antibiotics to which Cefazolin belongs, have been associated with toxic tendinopathy, although this is less frequent 2.
  • The onset of tendon pain following the initiation of treatment with a new medication, especially if the agent has previously been associated with drug-induced tendonitis, tendinosis, or tendon rupture, should prompt consideration of drug-associated toxic tendinopathy 2.

Related Antibiotics and Achilles Tendinitis

  • Fluoroquinolones, such as levofloxacin and ciprofloxacin, have been associated with Achilles tendinitis and tendon rupture 3, 4, 5, 6.
  • The risk of tendinopathy is increased in older patients and those with renal dysfunction 5.
  • Early diagnosis and treatment cessation may prevent tendon rupture, and tendinitis may resolve completely with subsequent physical therapy 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

To cipro or not to cipro: bilateral achilles ruptures with the use of quinolones.

Journal of the American Podiatric Medical Association, 2015

Research

An elderly patient with fluoroquinolone-associated achilles tendinitis.

The American journal of geriatric pharmacotherapy, 2008

Research

Tendinitis: the Achilles heel of quinolones!

Emergency medicine journal : EMJ, 2006

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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