Fosfomycin 3 g guide
How to prepare the single sachet for selected uncomplicated cystitis and recognise symptoms that need a different assessment.
How to use
- 01
Step 1
Dissolve one 3 g sachet in water
Empty the whole sachet into a glass of water, stir, and drink immediately. Do not swallow the granules dry and do not save part of the prepared solution.
- 02
Step 2
Take on an empty stomach
Take it about 2–3 hours before or after food, preferably at bedtime after emptying the bladder. The usual regimen for acute uncomplicated cystitis in women and female adolescents is one single 3 g dose.
Dose schedule
- 01
Step 1
One prescribed dose
Take the sachet once at the agreed time. Do not repeat it the next day unless a clinician has issued a different indication.
- 02
Step 2
Monitor over the next 2–3 days
Symptoms should be reassessed if they are worsening or not beginning to improve. Fever, flank pain, pregnancy, recurrent infection, or infection in men needs a different pathway.
Side effects
Digestive effects
Diarrhoea, nausea, abdominal discomfort, indigestion, and headache can occur. Drink normally unless you have been given a fluid restriction.
Antibiotic-associated reactions
Thrush can occur. Severe, persistent, or bloody diarrhoea can rarely indicate antibiotic-associated colitis and needs urgent advice; do not self-treat it with anti-diarrhoeal medicine.
04 · When to contact your doctor
Contact your doctor if
- Fever, chills, flank or back pain, vomiting, confusion, pregnancy, or feeling acutely unwell — seek prompt assessment
- A severe allergic reaction or severe, persistent, or bloody diarrhoea
- Symptoms worsen, do not start improving within 2–3 days, return soon, or blood remains in the urine
Storage
Keep in the original package, away from moisture and direct heat, and out of children's reach. Follow the temperature limit on your pack and do not use it after the expiry date.
What to expect
Fosfomycin is used for selected susceptible lower urinary infections; one sachet does not suit every urinary symptom and does not treat a kidney infection. Improvement is expected over the following days, but response varies and treatment failure requires reassessment rather than an unplanned repeat dose.