UF Health researchers find quinolone ear drops linked to tendon tears

Imagine a doctor prescribing antibiotic ear drops called quinolones to treat an ear infection. The non-exercising patient painfully ruptures the Achilles tendon a few weeks later, perhaps just walking across the living room.

Few would associate these ear drops with injury. It defies common sense.

However, University of Florida health researchers used data from 1.5 million Americans to demonstrate a small but not insignificant risk of tendon rupture after using quinolone ear drops, among the most commonly used drugs to treat ear infections.

In an article published last month in the journal Clinical Infectious Diseases, scientists found a more than fourfold increased risk of Achilles tendon rupture after using quinolone ear drops compared to other antibiotics.

The risk of all types of tendon tears was more than 1.5 times higher, the study noted. (A tear involves a partial or complete tear of a tendon that connects muscles to bones. Tears usually occur during vigorous exercise, such as playing sports or due to a fall.)

“It’s hard to imagine that something you put in the ear would affect the body in a pretty significant way,” said Patrick Antonelli, MD, study co-author and professor in the UF College of Medicine’s Department of Otolaryngology. “Patients should be counseled about such risks. And these risks must be weighed for each individual and each indication.

“Indication” is a medical term for a condition that a drug is intended to treat.

The researchers used a national database of private health insurance claims for patients aged 19 to 64. The study collected data from patients who were diagnosed with an ear infection or inflammation from 2005 to 2015 and were treated with either quinolone ear drops or other antibiotics.

An association with tendon tears was seen with quinolone ear drops, but not with the other antibiotics.

While it’s important to recognize the risk, it’s also important to understand that the side effect is unusual, said Antonelli and the paper’s lead author, Dr. Almut Winterstein, professor and chair of the Department of Pharmacy in the UF College of Pharmacy. and politics.

For example, the more than fourfold increased risk of Achilles tendon rupture was 6.17 cases per 100,000 patients.

“Incidence is low but elevated,” Winterstein said. “Our study shows that quinolone ear drops have enough systemic presence to affect other distant parts of the body, which sounds amazing because topical application in the ear is such a low dose.”

Oral quinolones have come under scrutiny in recent years because of their adverse effects on soft tissue and other problems. An advisory committee to the US Food and Drug Administration concluded last year that the benefits of oral quinolones may not outweigh the risks in certain cases. The committee also emphasized the need to understand the safety of topical applications of quinolones to soft tissues such as the ear.

Winterstein and Antonelli have shown in previous studies that the risk of perforated eardrum was significantly higher in children and adults who received quinolone ear drops compared to groups who received alternative, non-quinolone antibiotic ear drops.

Exactly how low-dose quinolone ear drops affect seemingly unrelated tissues remains unclear. Of course, scientists have seen tendon and joint problems in patients taking higher oral doses of quinolones to treat a number of conditions, including urinary tract infections and sinusitis.

But at a relatively small dose in the ear drops?

“There are different points of view on this,” Antontelli said. “But we don’t know for sure how such a small dose causes such a big problem.”

One hypothesis involves a cascade of effects at the cellular level after the antibiotic absorbed into the body damages the mitochondrial DNA in the affected tissue.

However, the mystery remains unsolved.

Antonelli began focusing on this oddity after an animal study conducted by his team yielded an unusual result. Quinolones were administered to one eardrum in rats that had both perforated eardrums. Opposite ears, untreated, served as controls. As expected, eardrums treated with quinolone drops healed more slowly than ears treated with saline. However, the opposite ear also healed slowly.

Antonelli and his team initially dismissed this finding, thinking it might be related to a steroid. Quinolone antibiotics often contain steroids to help reduce inflammation.

“After we thought about it a little longer, we started thinking, ‘Well, how do we really know it’s the steroid?’ How do we know the quinolone isn’t going the other way? Wow, could this be a systemic impact?” Antonelli said.

Proving that, Winterstein and Antonelli said, requires big data and can’t be achieved even in a clinical trial with hundreds of patients, given how rare the side effect is.

The UF Health team said more research is needed, including looking at what characteristics might make someone more susceptible to these quinolone-related tendon tears.

Patients – and even many doctors – could be forgiven for failing to make the connection between a ruptured Achilles tendon and a few antibiotic drops in their ear.

Winterstein and Antonelli want to spread the word so that medical professionals and their patients can make the right risk-benefit decision. For example, does it make sense to prescribe a non-quinolone alternative to an athlete?

“No one expects these effects,” Antonelli said. “It’s really there. Doctors do not advise patients: “Don’t run and don’t jump. Watch their activities in the weeks after using these ear drops.

Media Contact: Bill Levesque at [email protected] or 352-265-9417

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