What antibiotic can cause tendon issues? Understanding the Fluoroquinolone Risk

October 14, 2025 •

3 min read

As of 2016, the FDA updated its black box warning for the fluoroquinolone class of antibiotics due to the potential for serious, disabling, and potentially irreversible side effects affecting tendons, muscles, and nerves. These side effects raise a critical question for both patients and clinicians: What antibiotic can cause tendon issues? The answer lies primarily with the powerful and widely used fluoroquinolone drugs, which have been linked to tendinitis and, in severe cases, tendon rupture.

Quick Summary

Fluoroquinolone antibiotics, including ciprofloxacin and levofloxacin, are known to cause tendinitis and tendon rupture, with the Achilles tendon being most commonly affected. Risk factors include advanced age, concomitant corticosteroid use, and certain underlying medical conditions. Symptoms can appear during treatment or up to several months later, emphasizing the need for patient awareness and prompt medical intervention.

Key Points

Fluoroquinolones are the culprits: The class of antibiotics known as fluoroquinolones is the primary cause of drug-induced tendon issues like tendinitis and tendon rupture.
Achilles tendon is most vulnerable: The Achilles tendon is the most frequently affected site for tendon injuries caused by these antibiotics, but other tendons can also be involved.
Risk increases with age and steroids: Individuals over 60 and those taking concomitant corticosteroid medication are at a substantially higher risk of tendon rupture.
Symptoms can be delayed: Tendon pain and damage can manifest hours, days, or even months after starting or stopping fluoroquinolone treatment.
Immediate action is necessary: If you experience tendon pain, swelling, or a 'pop' during or after taking a fluoroquinolone, you should stop the medication and seek immediate medical attention.

The Fluoroquinolone Class: A Link to Tendon Injury

The most significant class of antibiotics linked to causing tendon issues is the fluoroquinolones. These broad-spectrum antibiotics are effective against a wide range of bacterial infections but carry a risk of adverse musculoskeletal effects, particularly on tendons. The U.S. Food and Drug Administration (FDA) has repeatedly issued safety communications and mandated black box warnings for these drugs, highlighting the risk of tendinitis and tendon rupture. While the risk is relatively low, the consequences can be severe and even permanent.

How Do Fluoroquinolones Affect Tendons?

The precise way fluoroquinolones damage tendons is still being researched, but it is believed they disrupt the tendon's structure. This may involve interfering with collagen synthesis, causing oxidative stress in tendon cells, or increasing enzymes that degrade the tendon's components.

Common Fluoroquinolone Antibiotics Associated with Tendon Issues

Several fluoroquinolone drugs are commonly linked to tendon problems, including Ciprofloxacin (Cipro), Levofloxacin (Levaquin), and Moxifloxacin (Avelox). Ciprofloxacin and Levofloxacin have been particularly associated with Achilles tendon issues and an increased risk of rupture.

Identifying Symptoms of Fluoroquinolone-Induced Tendon Damage

Symptoms of tendinopathy can appear from hours to months after starting or finishing treatment with fluoroquinolones. Look for pain, swelling, and tenderness near a tendon, stiffness, or a grinding sensation during movement. A sudden, severe pain with a 'snap' or 'pop' indicates a potential tendon rupture.

Key Risk Factors for Fluoroquinolone-Associated Tendonopathy

Certain factors increase the likelihood of developing tendon issues with fluoroquinolones. These include being over 60, taking corticosteroids concurrently (which significantly raises the risk), having received an organ transplant, and having underlying conditions like chronic kidney disease or diabetes. High physical activity levels may also be a risk factor.

Management and Prevention

Patients at high risk should discuss alternative antibiotics with their doctor. If tendon pain occurs while taking a fluoroquinolone, stop the medication immediately and contact your healthcare provider to switch to a different antibiotic. Rest and ice can help reduce swelling. Medical attention may be needed for rest, immobilization, and physical therapy. Avoid corticosteroid injections directly into the tendon as they can weaken it further.

Comparison of Fluoroquinolones and Related Risk Factors


Feature	Ciprofloxacin (Cipro)	Levofloxacin (Levaquin)	Moxifloxacin (Avelox)
Tendonitis Risk	Statistically significant association with tendonitis.	Statistically significant increased risk.	Relatively weaker signal strength compared to Cipro and Levaquin.
Tendon Rupture Risk	Increased risk, especially in the presence of other risk factors.	Highest statistical association with tendon rupture based on FAERS data.	Lower risk compared to other fluoroquinolones.
Commonly Affected Tendon	Achilles tendon is frequently involved.	Achilles tendon, rotator cuff, and others.	Achilles tendon.
Patient Monitoring	Especially important for high-risk patients (elderly, steroid users, transplant patients).	Requires close monitoring for signs of tendon damage.	Vigilance recommended, especially for musculoskeletal symptoms.

Conclusion

Fluoroquinolone antibiotics are the primary cause of drug-related tendon issues. While the risk of tendinopathy is generally low, it is significantly higher for individuals who are older, taking corticosteroids, or have certain medical conditions. Patients should be aware of the symptoms, and healthcare providers should carefully consider risks and alternative treatments, especially for less severe infections. Discontinuing the medication promptly at the first sign of tendon pain is crucial to prevent further damage. For more information, resources like the MedlinePlus drug information page for Levofloxacin are available.

Frequently Asked Questions

The class of antibiotics known as fluoroquinolones is primarily responsible for causing tendon problems. Specific examples include ciprofloxacin (Cipro), levofloxacin (Levaquin), and moxifloxacin (Avelox).

The Achilles tendon, located at the back of the ankle, is the most common site of injury. However, other tendons in the shoulder (rotator cuff), hand, and knee (patellar) can also be affected.

Major risk factors include being over 60 years old, concurrent use of corticosteroids (steroids), having had an organ transplant, and pre-existing kidney disease.

Symptoms can appear rapidly, sometimes within hours of the first dose. However, they can also be delayed, presenting days, weeks, or even up to several months after you have finished the antibiotic course.

If you experience any tendon pain, swelling, or inflammation, you should stop taking the fluoroquinolone immediately, rest the affected area, and contact your doctor. Your doctor will likely switch you to a different class of antibiotic.

While tendinitis often resolves with rest and appropriate management after discontinuing the medication, a tendon rupture is a much more serious injury and can result in lasting disability. In some cases, the FDA notes the side effects can be potentially irreversible.

Following FDA safety updates, the use of fluoroquinolones is now restricted for certain mild-to-moderate infections, such as uncomplicated urinary tract infections or acute sinusitis, in patients with other available treatment options. They are generally reserved for more serious or resistant infections.