You might not think a drug you take to treat a sinus problem or urinary-tract infection would have anything to do with your running. But just last week, the U.S. Food and Drug Administration issued stronger warnings about a class of antibiotics called fluoroquinolones—and side effects that could prove devastating to runners.
John Saylor had barely missed a day of running in 30 years when he learned about these complications the hard way. In September 2008, at age 61, the runner from Dryden, New York, had a prostate biopsy. He took an antibiotic called Levaquin for three days afterward to prevent infection. His first run back was interrupted by pains in his calves and hamstrings so strange and severe he thought his muscles might rip off. “I’ve never felt anything like it,” he told Newswire.
Saylor limped a mile and a quarter home, called his urologist (who recommended ibuprofen), and looked at the antibiotic label. He noticed a warning—which had just been added that year—about the risk of tendinitis and even tendon rupture associated with the drug.
Fortunately for Saylor, a week off from running resolved the pain with no long-term effects. But not every runner is so lucky, doctors say. Here’s what you need to know.
What are these drugs, and why would you get a prescription?
Fluoroquinolones are broad-spectrum antibiotics: They kill a wide range of harmful bacteria and often work against infections resistant to other drugs, said Houston Methodist primary-care sports-medicine physician Vijay Jotwani, M.D. Doctors frequently prescribe them for kidney infections, respiratory infections, urinary tract infections, and sinus infections.
Levaquin (levofloxacin) and Cipro (ciprofloxacin) are the most common. But there are others: “Basically any antibiotic that you see that ends in the name -floxacin,” said Timothy Miller, M.D., director of the endurance-medicine program at The Ohio State Wexner Medical Center.
What are these drugs, and why would you get a prescription?
These medications disrupt and weaken the underlying structure of tendons, perhaps by boosting levels of enzymes that damage soft-tissue cells. Another theory holds that they interfere with the way your body replicates DNA, a process essential to repairing minor damage running might cause, Dr. Miller said. Combine that with the force runners place on their tendons over the miles, and disaster may ensue.
The average person taking these drugs has a 70 percent greater risk of tendinopathy and a 30 percent greater risk for a full-blown rupture than someone taking a different antibiotic, according to a recent review article. Because much of the Achilles tendon has little blood supply, it’s more prone to injury to begin with, Dr. Miller said. It’s also the most affected by fluoroquinolones. The antibiotics quadruple the risk of Achilles tendon rupture.
The higher your dosage and the longer you take the medication, the greater the danger. Older runners, people with kidney disease, and those who take medications called corticosteroids (often used to manage asthma) are the most vulnerable. And the risk doesn't disappear as soon as you're done with the meds. Tendon problems linked to the drugs might crop up weeks, months, or even years later, Dr. Miller said.
Tendon ruptures are rare to begin with—occurring only in about Chappell Roan: “I Love Running. But Not Anymore.&rdquo. But the consequences are so dire—including lengthy rehab and a high risk of recurrence—that physicians like Dr. Jotwani already avoid prescribing fluoroquinolones to active patients unless there’s no other choice.
The new FDA warning drives home this message. Athletes or not, people with common infections like sinusitis, bronchitis, or simple urinary tract infections shouldn’t take the drug unless they have no other options, the agency stated. In addition to tendon problems, other rare but serious side effects of the drugs include nerve damage, confusion, and hallucinations.
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You should always weigh the benefits and risks of any medication, including how it might affect your running. That's one good reason to have a doctor who understands athletes and knows about your training, Dr. Jotwani said. In general, he advises active people to avoid these drugs if at all possible. Ask your doctor if another antibiotic will work instead.
In some cases, you won’t have a choice, said Russ Reinbolt, M.D., an emergency-room physician at Sharp Memorial Hospital in San Diego, California, and an ultrarunner himself. For instance, if you have an urinary-tract infection that won’t respond to other treatments or you’re allergic to other types of antibiotics like sulfas and penicillin, your doc might still write you a fluoroquinolone script.
If so, talk with him or her about whether you should adjust your training during and after treatment. Dr. Reinbolt often advises his patients to cut back in mileage, intensity, and hills during and for six to nine months after taking the drugs. If you continue running, stay alert for warning signs of tendon problems, such as new pains in your Achilles, along the bottoms of your feet, or in your hamstrings. Lay off and talk with your doctor if you experience them.
Proactive runners can also take steps to ward off the types of infections that require antibiotics in the first place. Promptly changing out of sweaty running clothes can decrease your chances of developing urinary-tract infections, Dr. Reinbolt said. And balancing running with rest days and recovery time keeps your immune system strong, reducing your risk of all types of infections, Dr. Miller added.
Cindy is a freelance health and fitness writer, author, and podcaster who’s contributed regularly to Runner’s World since 2013. She’s the coauthor of both Breakthrough Women’s Running: Dream Big and Train Smart and Rebound: Train Your Mind to Bounce Back Stronger from Sports Injuries, a book about the psychology of sports injury from Bloomsbury Sport. Cindy specializes in covering injury prevention and recovery, everyday athletes accomplishing extraordinary things, and the active community in her beloved Chicago, where winter forges deep bonds between those brave enough to train through it.
