Antibiotics are prescribed to treat infections from head to toe—from bronchitis to urinary tract infections (UTIs). But doctors and patients are increasingly learning more about the alarming side effects of one particular class called fluoroquinolones, which include Cipro and Levaquin. Rare cases of severe tendon damage associated with the use of the drug, among other side effects, have been reported in recent years.
Now, experts want both doctors and patients to be more aware of these potential dangers. Prescribing fluoroquinolone antibiotics more judiciously can help control the spread of resistant infections while reducing who experiences the side effects.
Doctors say tendon issues weren't apparent in the 1970s, when thousands of people tested fluoroquinolones in trials before the drugs were approved. As these medications became popular for treating many common infections, including pneumonia, sinusitis, bronchitis and UTIs, the side effect started to emerge.
It's not clear how the drugs contribute to tendon issues, but they believe that the antibiotics may affect blood flow to collagen in the muscles, which makes up tendons. There were enough cases that in 2008, the Food and Drug Administration (FDA) added a black box warning to the drugs about the risk of tendonitis. In 2013, the FDA included a warning about permanent nerve damage linked to the drugs as well. And last May, the agency advised that fluoroquinolones should only be used as a last-resort antibiotic after other classes were tried and didn’t work to control uncomplicated infections.
Medical groups took the FDA’s lead. In recent years, organizations including the Infectious Diseases Society of America, the American Thoracic Society and the American College of Obstetricians and Gynecologists went from recommending the class of drugs as a first-line treatment to one that should be considered only after other antibiotics have failed.
That advice is taking longer to trickle down to individual doctors and patients, however. Studies show little drop in the prescription of fluoroquinolones outside of the hospital.
There's yet another reason why some doctors are moving away from fluoroquinolones as a first choice. When people overuse any kind of antibiotic, bacteria can become resistant to the drugs, rendering whole classes of antibiotics ineffective. And of the different antibiotics, fluoroquinolones appear to be especially susceptible to creating resistant bugs. Though they used to be 100% effective in destroying bacteria associated with infections like sinusitis and UTIs, for example, now they're only 70% effective, says Dr. B. Joseph Guglielmo, professor and dean of University of California San Francisco School of Pharmacy. “[That] was not anticipated when these drugs first came out," he says. "Everybody thought they were these wonderful antibiotics. But bacteria are always smarter than us eventually.”
When these drugs were shown to be less effective, their side effects became more crucial to consider, since doctors weigh the benefits of controlling an infection with the risks of the drug. “What’s starting to happen is that as the efficacy question becomes more and more important, the toxicity question becomes more and more important,” says Guglielmo. “If you have a drug that isn’t providing the value that it used to, then you get back to considering the reasons not to use it.”
Some studies suggest that the tendon problems with fluoroquinolones may be more common among older people and those taking steroid drugs. Before prescribing this class of antibiotics, doctors should ask patients about their steroid use and whether they have had previous issues with their tendons or muscles. Being better informed about antibiotics and their potential side effects may help doctors decide whether someone really needs one—and if so, what kind to prescribe.