Fosfomycin – Quick Guide to This UTI Antibiotic

If you’ve ever gotten a urinary tract infection (UTI), you might have heard doctors mention fosfomycin. It’s a single‑dose antibiotic that’s been around for decades, but many people still wonder how it works, when to use it, and what to expect. Here’s a no‑fluff rundown so you can feel confident if it’s prescribed for you.

How Fosfomycin Works

Fosfomycin attacks bacteria by blocking a key step in building their cell wall. Without a strong wall, the germs burst and die. Because it targets a part of the bacteria that most other antibiotics don’t, it’s useful against strains that have become resistant to common drugs like trimethoprim‑sulfamethoxazole.

The drug is taken as a powder that you dissolve in water and swallow just once. That one dose stays in your urinary tract for about 48 hours, delivering enough exposure to clear most uncomplicated UTIs.

Key Tips for Safe Use

Even though it’s a single dose, getting the details right matters. Take the medication on an empty stomach – at least two hours before or after eating – because food can lower absorption. Drink plenty of water before and after the dose to help flush the bacteria out of your system.

Typical dosing for adults is a 3 gram packet of fosfomycin tromethamine, mixed with a glass of water. Kids over 12 years old usually get the same dose, but younger children may need a different formulation prescribed by a pediatrician.

Common side effects are mild: a bit of nausea, diarrhea, or a temporary change in taste. If you notice a rash, swelling, or trouble breathing, call your doctor right away – those could be signs of an allergic reaction.

Because fosfomycin stays in the bladder for a while, it’s not the first choice for infections that have spread to the kidneys or for complicated UTIs. Your doctor will run a urine culture if you’ve had multiple infections; this helps confirm that fosfomycin will hit the right bugs.

Resistance is a growing concern with any antibiotic. Fosfomycin resistance is still relatively low, but misuse can speed it up. Don’t use leftover pills, and don’t take it for a different infection without medical advice.

In short, fosfomycin is a convenient, single‑dose option for many uncomplicated UTIs. Follow the empty‑stomach rule, stay hydrated, and watch for any side effects. If you’re unsure whether it’s right for you, ask your pharmacist or doctor for a quick clarification – they’ll know if another drug would work better for your situation.