In the US, it is only available as a powder formulation of fosfomycin tromethamine, which are dissolved in liquid and can be taken orally. Outside the US are administered i.v. Formulations available.
Fosfomycin is a new class of anti-bacteria with a chemical structure unrelated to other known antibiotics. It is a bactericidal substance that disrupts the cell wall synthesis by inhibiting phosphoenolpyruvate synthetase and thus acts on the production of peptidoglycan. In the US, it is only available as a powder formulation of fosfomycin tromethamine, which are dissolved in liquid and can be taken orally. Outside the US are administered i.v. Formulations available. Pharmacology Fosfomycin is well absorbed orally and penetrates well into the tissue, including sequestered sites such as the prostate and cerebrospinal fluid. The oral bioavailability of fosfomycin tromethamine salt is low (about 40%) and consequently the serum levels relative to the minimum inhibition concentrations (MICs) are low. For this reason the drug for treatment of uncomplicated lower UTI is used and not with pyelonephritis. Fosfomycin is excreted in the urine mainly by glomerular filtration without biotransformation. After oral ingestion, urine levels exceed the MICs susceptible pathogens for over 24 hours. Indications fosfomycin has a broad spectrum of activity against both gram-positive and gram-negative organisms, including many antibiotic-resistant organisms such as Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) Enterococcus sp, including vancomycin-resistant enterococci (VRE), Enterobacteriaceae, including Extended -spectrum-?-lactamase (ESBL) -producing K. pneumoniae and Escherichia coli Pseudomonas aeruginosa, the variable intrinsic resistance rates has fosfomycin is used especially in uncomplicated (ie lower) UTI caused by E. coli or E. faecalis , However, since it has a broad spectrum of activity, fosfomycin is sometimes used to treat infections with multidrug-resistant organisms in other anatomic sites. Contraindications There are no contraindications for its use in addition to a known hypersensitivity to fosfomycin or towards a component of the formulation. Fosfomycin side effects is well tolerated in general and has a low rate of side effects, which mainly gastrointestinal symptoms (eg. B., diarrhea nausea) belong. Considerations for metering In uncomplicated UTI is a single oral dose of fosfomycin trometamol 5.61 g (corresponding to 3 g of fosfomycin), which is dissolved in the liquid applied. Figure 1 shows a longer course of treatment is likely for infections at other sites (eg. As prostate) necessary. 1Falagas ME, Giannopoulou KP, Kokolakis GN, Rafailidis PI: fosfomycin: Use beyond urinary tract and gastrointestinal infections. Clin Infect Dis. 46 (7): 1069-1077., 2008