Fosfomycin (Phosphomycin or phosphonomycin) : Uses, Dosage, Side Effects, Interactions, & Contraindications

Fosfomycin : Therapeutic uses, Clinical uses, Indications, Dosage, Side Effects, Warnings, Interactions, Precautions, Contraindications & Brand names

Fosfomycin (Phosphomycin or phosphonomycin) is a synthetic derivative of phosphonic acid. It is is used for treating uncomplicated urinary tract infections in women caused by certain bacteria.
Dose :  3 g
Route : Oral
Onset of action : ?
Plasma Half-life : 3-8 hours
Duration of action : ?
Bioavailability : 30–37%, food interfere with absorption
Plasma protein binding : Nil
Metabolism : Nil
Pregnancy risk category : B
Chemical formula : C3H7O4P
IUPAC name : [(2R,3S)-3-methyloxiran-2-yl]phosphonic acid
Trade name : Monurol, Monuril
Antibacterial spectrum : Fosfomycin has broad antibacterial activity against both Gram-positive & Gram-negative pathogens such as E. faecalis, E. coli, Citrobacter and Proteus. Activity against extended-spectrum β-lactamase-producing pathogens, notably ESBL-producing E. coli, is good to excellent, because the drug is not affected by cross-resistance issues. It is a bactericidal drug.
Therapeutic uses : Fosfomycin is indicated for urinary tract infections caused by E. coli or E. faecalis. It maintains high concentrations in the urine over several days, allowing for a one-time dose for the treatment of urinary tract infections. It is not indicated for the treatment of pyelonephritis or perinephric abscess.
Its parenteral formulation has been used for the treatment of systemic infections.
Mechanism of action : Fosfomycin inhibits bacterial cell wall synthesis by inhibiting the enzyme UDP-N-acetylglucosamine enolpyruvyl transferase, which catalyzes the first step in peptidoglycan synthesis. Due to its unique structure and mechanism of action, cross resistance with other antimicrobial agents is unlikely.
Side effects : Fosfomycin may cause following side effects such as :

  • Diarrhea, nausea, abdominal pain
  • Vaginitis, dysmenorrhea
  • Headache, dizziness
  • Rhinitis, pharyngitis, skin rash

Drug Interactions 

  • Fosfomycin Χ BCG vaccine, cholera vaccine, typhoid vaccine, lactobacillus, estriol, sodium picosulfate : Antibiotics may diminish the therapeutic effect of thsese drugs.


  • Superinfection


  • Concurrent drug therapy issues (Drug-drug interactions)

Before using this medication, tell your doctor or pharmacist

  • If you are allergic to it; or if you have any other allergies.
  • Your medical history.


  • Contraindicated in persons known to hypersensitive to this drug.

For detailed query or in case of uncertainty, Always consult your doctor or pharmacist.

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