Fosfomycin

Antibiotic Class:

Phosphonic acid derivative

Antimicrobial Spectrum:

Gram-positive: Staphylococcus spp., Enterococcus spp.

Gram-negative: E. coli, Enterobacter spp., Citrobacter spp., Klebsiella spp., Proteus spp., Providencia spp. P. aeruginosa

Mechanism of Action:

Irreversibly attaches to pyruvyl transferase, an important enzyme in the early step of bacterial cell wall synthesis

Pharmacodynamics:

No data

Pharmacokinetics:

C_max: 26.2±8.1mcg/ml; Half-life: 3.6±0.44 (hr); T_max: 2.5±0.8 (hr); Table 2

Adverse Effects:

GI: diarrhea, nausea, abdominal pain

Other: vaginitis, headache, dizziness

Dosage:

PO: Powder for reconstitution

UTI in children < 5 years old: 2g once

UTI in Adults: 3g once

Disease state based dosing:

Renal failure: Dosing adjustments not necessary

Hepatic failure: Dosing adjustments not necessary

Contraindications/Warnings/Precautions:

Precautions:  Food delays absorption – administer on an empty stomach

Drug Interactions:

Cisapride: decreased urinary concentrations of fosfomycin

Metoclopromide: decreased urinary concentrations of fosfomycin

Pregnancy:

Category B: No evidence of risk in humans but studies inadequate.

Monitoring Requirements:

Therapeutic:  Culture and sensitivities, signs and symptoms of infection

Toxic:  None

Brand names/Manufacturer: