When doctors prescribe fluoroquinolones, a class of broad-spectrum antibiotics used for serious bacterial infections. Also known as FQs, they include drugs like ciprofloxacin, levofloxacin, and moxifloxacin. These aren’t your everyday antibiotics—they’re reserved for life-threatening infections like pneumonia, kidney infections, or anthrax exposure because of how strong they are and how dangerous their side effects can be.
Fluoroquinolones work by smashing bacterial DNA, which stops infections fast. But that same power can hurt your own body. The FDA has issued multiple black box warnings for these drugs because they can cause tendon rupture, a sudden, painful tear often in the Achilles tendon, even in healthy people. It can happen within hours or weeks after starting the drug. They also raise the risk of QT prolongation, a heart rhythm problem that can lead to sudden cardiac arrest, especially in older adults or those on other heart medications. And unlike most antibiotics, fluoroquinolones don’t just kill bad bacteria—they wreck your gut microbiome, making yeast infections and C. diff more likely.
These drugs are also fueling antibiotic resistance, a global crisis where bacteria evolve to survive even the strongest drugs. Because fluoroquinolones are so effective, they’ve been overprescribed for simple sinus infections, urinary tract infections, and even acne—conditions where safer, narrower-spectrum antibiotics would work just fine. That overuse is why many hospitals now restrict them to only the most serious cases.
People who’ve taken fluoroquinolones often report long-term issues: nerve pain, brain fog, fatigue, and muscle weakness that last months or years. The FDA calls this "fluoroquinolone-associated disability"—a real, documented problem that’s not just in rare cases. If you’ve been on one of these drugs and still feel off, you’re not imagining it.
Below are real-world stories and medical insights from people who’ve dealt with these drugs—whether they were prescribed for a serious infection, had unexpected side effects, or are now managing the aftermath. You’ll find what works, what doesn’t, and how to protect yourself if you’re ever asked to take one.
Fluoroquinolone antibiotics like ciprofloxacin and levofloxacin carry a serious risk of tendon rupture, especially in older adults and those on steroids. Learn the signs, who's most at risk, and what to do if you're prescribed one.