Besifloxacin: What It Is, How It Works, and What You Need to Know

When your eyes are red, swollen, or burning from a bacterial infection, besifloxacin, a prescription antibiotic eye drop used to treat bacterial conjunctivitis. Also known as Baxdela, it belongs to the fluoroquinolone class of antibiotics and is designed to kill bacteria right where they live—in the eye. Unlike oral antibiotics, besifloxacin is applied directly to the eye, so it works fast without affecting your whole body. This makes it a go-to choice for doctors treating pink eye caused by common bacteria like Staphylococcus aureus or Streptococcus pneumoniae.

Besifloxacin isn’t just another eye drop. It’s one of the few topical antibiotics approved by the FDA specifically for bacterial conjunctivitis that doesn’t require preservatives like benzalkonium chloride. That’s important because preservatives can irritate sensitive eyes, especially if you’re using the drops multiple times a day. The formulation is built to stay on the eye’s surface longer, giving it more time to work. It’s also used when other antibiotics fail—like if you’ve tried tobramycin or ciprofloxacin and the infection didn’t clear up. In those cases, besifloxacin’s unique structure helps it penetrate bacterial cell walls more effectively.

People often wonder how besifloxacin compares to other eye antibiotics. It’s not the cheapest option, but it’s often prescribed because it’s potent and doesn’t need to be used as often as some others. Most patients use it three times a day for just seven days. That’s fewer doses than older treatments like erythromycin or sulfacetamide, which might need five or six applications daily. For busy parents, shift workers, or anyone juggling a full schedule, that convenience matters. And because it’s a fluoroquinolone, it’s effective against a broad range of bacteria, including some that are resistant to older antibiotics.

But it’s not magic. If your eye infection doesn’t improve in a few days, or if it gets worse, you need to see a doctor. Sometimes what looks like pink eye is actually a virus, an allergy, or even a corneal scratch—and antibiotics won’t help those. Overusing or misusing antibiotics like besifloxacin can lead to resistant strains, which makes future infections harder to treat. That’s why it’s always prescribed, never sold over the counter. Your pharmacist will check your history to make sure it’s the right choice, especially if you’re using other eye drops or have had eye surgery before.

There are also things to watch for. A mild stinging or burning sensation right after applying the drops is normal. But if your vision blurs, your eye swells up, or you develop a rash around your eye, stop using it and call your doctor. Rarely, fluoroquinolones can cause serious side effects in other parts of the body—even when used as eye drops—so it’s important to follow instructions exactly.

Below, you’ll find real-world insights from patients and professionals about how besifloxacin fits into broader treatment patterns. You’ll see how it stacks up against other eye antibiotics, what doctors look for when choosing it, and how it connects to bigger issues like antibiotic resistance, prescription costs, and proper eye care. Whether you’re on it now, considering it, or just curious, this collection gives you the facts without the fluff.