Pronunciation: foss-foe-MY-sin troe-METH-ah-meen
Class: Anti-infective, Antiseptic
- Granules 3 g
Interferes with bacterial cell wall biosynthesis.
Absolute bioavailability is 37% while fasting; it is reduced 30% with food. C max is about 26 mcg/mL while fasting; about 17.6 mcg/mL with a high-fat meal. T max is 2 h, about 4 h with a high-fat meal.
Mean Vd ss is about 136 L. Fosfomycin is 0% protein bound. It distributes to the kidneys, bladder wall, prostate, seminal vesicles, and crosses the placental barrier.
About 38% is excreted in urine unchanged and about 18% from the feces. Mean t 1/ 2 is about 5.7 h.
Special PopulationsRenal Function Impairment
The t 1/ 2 is 40 h in hemodialysis patients. Patients with Ccr 7 to 54 mL/min have a t 1/ 2 of 11 to 50 h, and urinary excretion decreases to 11%.
Indications and Usage
Treatment of uncomplicated UTI (acute cystitis) in women caused by susceptible strains of specific microorganisms.
Dosage and AdministrationAdult Women
PO One 3 g sachet dissolved in 3 to 4 oz of cool water.
- Never take in dry form; always mix with water, but do not use hot water. Pour the entire contents of the single-dose sachet into 3 to 4 oz of water and stir to dissolve.
- Administer immediately after mixing; may be taken with or without food.
Store dry powder at room temperature (59° to 86° F).
May decrease serum concentrations and urinary excretion of fosfomycin.
Laboratory Test Interactions
None well documented.
Diarrhea; nausea; dyspepsia; abdominal pain.
Asthenia; back pain; pain.
Category B .
Safety and efficacy not established.
No dosage adjustment necessary.
Do not use more than 1 single dose to treat a single episode of infection.
- Instruct patient in proper preparation of medication.
- Inform patient that this is a single-dose treatment and repeated doses do not improve the clinical success.
- Advise patient that symptoms should improve in 2 to 3 days after taking drug. If symptoms do not improve, instruct patient to contact health care provider.
- Increase fluid intake to 2,000 to 3,000 mL/day.
- Instruct the patient on proper personal hygiene to help prevent recurrence of infections.
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