Category: Pharmacology & Therapeutics
Keywords: Fosfomycin, urinary tract infection, cystitis (PubMed Search)
Fosfomycin is an antibiotic infrequently used for the treatment of urinary tract infections (UTIs). It has a broad spectrum of activity that covers both gram-positive (MRSA, VRE) and gram-negative bacteria (Pseudomonas, ESBL, and carbapenem-resistant Enterobacteriaceae), which is useful in the treatment of multidrug-resistant bacteria.
Fosfomycin is FDA approved for the treatment of uncomplicated UTIs in women due to susceptible strains of Escherichia coli and Enterococcus faecalis (3g oral as a single dose). Data has also demonstrated that it can be used for complicated UTIs; however, dosing is different in this population (3 g oral every 2-3 days for 3 doses). Fosfomycin is not recommended for pyelonephritis.
The broad spectrum of activity, in addition to only needing a single dose in most cases, makes fosfomycin an attractive option; however, it should be reserved for use in certain circumstances. Fosfomycin should not be considered as a first-line option. It is also more expensive than other medications (~$100/dose) and in countries with high rates of utilization bacteria are developing resistance to fosfomycin. In addition, most outpatient pharmacies do not keep this medication in stock.
Fosfomycin should be reserved for multidrug-resistant UTIs in which other first-line options have been exhausted.
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