ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.
Overview
It's useful for some resistant infections.
What it's used for
- Uncomplicated bladder infections
How to take it
- Mix the packet in 3 to 4 ounces of cold water, stir, and drink right away.
- Symptoms may take 2 to 3 days to improve.
Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.
Side effects
Common side effects
- Diarrhea
- Nausea
- Headache
Call your provider todayFever, back pain, or vomiting (possible kidney infection)
Call your provider todaySevere watery or bloody diarrhea, even weeks after finishing (possible C. diff infection)
Warnings
- Not for kidney infections.
Other medicines, foods, and alcohol
- Metoclopramide lowers its level.
Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.
Pregnancy and breastfeeding
Can be used in pregnancy.
Missed doses, overdose, and storage
If you miss a dose
Not applicable: it's a single dose.
If someone takes too much
Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.
Storing it
Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.
Conditions it's used for
Sources
- DailyMed: FDA drug label for Fosfomycin (U.S. National Library of Medicine)
- MedlinePlus: Drugs, herbs, and supplements
- FDA: Drugs@FDA
Last updated 2026-11-13.