Infectious Disease Compendium

Fosfomycin

Dosing

CrCl Formula

It comes in the ever so quaint sachet.

Women: years: 3 g PO once. I suspect this is insufficient and likely cystitis needs 3 or more doses, which is why it was inferior to nitrofurantoin for UTI (PubMed).

Males: 3 g every 2-3 days for 3 doses.

IV is 8-24 grams a day. IV not available in US.

Important side effects

IV has a lot of sodium.

Important drug interactions

Rants and Screeds

Pearls

It can be synergistic with beta-lactams.

Effective against E. faecalis, E. coli, Citrobacter and Proteus. Pseudomonas may have more ability to be resistant, but less perhaps than other antibiotics.

May be useful with MDRO and XDR (PubMed).

Resistance is rare in the US but common in China. US resistance variable, more in Klebsiella than E. coli (Review).

Treatment of choice

Use for

UTI (PubMed).

Maybe prostatitis, where it is given for 6 to 8 weeks.

Don't use for

Pyelonephritis.

Class

Phosphonic acid derivative, it inhibits bacterial cell wall synthesis.

Curious Cases

Relevant links to my Medscape blog

Can't Get It Done

Last update 11/25/19