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

When you have a stubborn urinary tract infection, your doctor might reach for fosfomycin, a broad-spectrum antibiotic that kills bacteria by disrupting their cell wall formation. Also known as Monurol, it’s often used when other antibiotics fail or when resistance is a concern. Unlike many antibiotics that you take for days or weeks, fosfomycin is usually given as a single dose—simple, fast, and surprisingly effective for common infections like cystitis.

Fosfomycin doesn’t just target one type of bacteria. It works against both Gram-positive and Gram-negative strains, including some that have learned to resist common drugs like amoxicillin or ciprofloxacin. That’s why it’s becoming a go-to option in clinics dealing with antibiotic resistance, the growing global problem where bacteria evolve to survive standard treatments. It’s also used off-label for more complex infections, like kidney infections or infections after surgery, especially when other drugs aren’t working or can’t be taken due to allergies.

One of the biggest advantages of fosfomycin is how little it disrupts your gut. While antibiotics like cefprozil or amoxicillin can wipe out good bacteria and lead to diarrhea or yeast infections, fosfomycin mostly stays in the urinary tract. That’s why it’s often recommended for people who’ve had bad reactions to other antibiotics. But it’s not perfect—it can still cause nausea, headaches, or dizziness in some people. And if you’re taking it for something beyond a simple UTI, your doctor might check your kidney function first, since it’s cleared through the kidneys.

It’s also worth noting that fosfomycin is often used in combination with other antibiotics for serious infections. For example, in hospital settings, it might be paired with vancomycin or gentamicin to fight off multi-drug-resistant bugs. This isn’t something you’d do at home—it’s reserved for cases where the infection is aggressive or the patient is at high risk.

You won’t find fosfomycin on every pharmacy shelf. It’s not always the first choice because it’s more expensive than older antibiotics, and in some places, it’s only available by prescription or through special order. But when it’s needed, it’s often the only thing that works. That’s why it’s showing up more in guidelines from the CDC and WHO as a critical tool in the antibiotic arsenal.

What you’ll find in the posts below isn’t just a list of articles—it’s a practical guide to how fosfomycin fits into real-world treatment. You’ll see how it compares to other antibiotics, what patients actually experience when they take it, how doctors decide when to use it, and why it matters more now than ever. Whether you’re dealing with a recurring UTI, worried about antibiotic side effects, or just trying to understand why your doctor chose this particular drug, the information here cuts through the noise and gives you what you need to know.