Fosfomycin

How it works

It irreversibly inhibits MurA (UDP-N-acetylglucosamine enolpyruvyl transferase), blocking an early step in bacterial cell-wall peptidoglycan synthesis and so killing the organism.

Prescribing in practice

• Confirm the diagnosis is uncomplicated lower UTI before use; efficacy depends on adequate urinary concentrations, so it is not appropriate for pyelonephritis or other upper/complicated urinary tract infection unless specifically advised.
• Take on an empty stomach, ideally at bedtime after emptying the bladder, dissolved in water; for treatment courses a second sachet may be advised after an interval per the SPC.
• Resistance and reduced activity occur with some organisms, so prescribe according to local susceptibility data and resistance patterns.

Monitoring

Routine laboratory monitoring is not required; review clinically and arrange urine culture if symptoms persist or recur.

Counselling the patient

• Dissolve the whole sachet in a glass of cold water and drink immediately on an empty stomach, preferably before bed.
• Return if symptoms do not settle within a few days or worsen.

Evidence & guidelines

Single-dose fosfomycin trometamol is recommended in NICE and UK antimicrobial guidance as an option for uncomplicated UTI, particularly where resistance limits other agents.