[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/) › Fosfomycin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)

# Fosfomycin

A small antibiotic that blocks the first step of cell-wall building. One oral sachet treats uncomplicated cystitis; an IV form is a WHO reserve drug.

Updated 2026-11-01

- Class: [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)
- Enzyme: UDP-N-acetylglucosamine enolpyruvyl transferase (MurA)
- ATC code: J01XX01
- WHO Model List of Essential Medicines

✂**UDP-N-acetylglucosamine enolpyruvyl transferase (MurA)**Fosfomycin

ⓘ The figure shows Escherichia coli MurA with fosfomycin bonded covalently to its active site (the ligand is the opened fosfomycin adduct).

**Target in 3D:** UDP-N-acetylglucosamine enolpyruvyl transferase (MurA). PDB structure 1UAE (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1UAE) · Drag to rotate · pinch to zoom

## Mechanism of action

Fosfomycin mimics phosphoenolpyruvate and binds MurA, the enzyme that starts peptidoglycan synthesis by joining phosphoenolpyruvate to UDP-N-acetylglucosamine. It forms a covalent bond in the active site, so the enzyme is permanently blocked and the bacterium cannot build its wall. It is bactericidal.

- Enters the bacterium through sugar-phosphate transporters
- Mimics phosphoenolpyruvate at MurA
- Bonds covalently and blocks the enzyme
- Cell-wall synthesis stops and the bacterium dies

## Pharmacokinetics

**Absorption**
Oral granules of fosfomycin tromethamine, dissolved in water.

**Distribution**
High urinary levels for a long time after a single dose.

**Elimination**
Unchanged in the urine and faeces.

**Half-life**
About 5.7 hours after an oral dose.

## Indications

- Uncomplicated cystitis in women due to E. coli or Enterococcus faecalis [Urinary tract infection (acute cystitis) →](https://durgical.com/en/conditions/urinary-tract-infection/)
- IV fosfomycin for multidrug-resistant infections (WHO «Reserve» group)

## Adverse effects

### Common

- Diarrhoea
- Headache and nausea
- Vaginal infection

### Serious (rare, important)

- Allergic reactions, including anaphylaxis (rare)
- C. difficile diarrhoea

## Contraindications

- Known allergy to fosfomycin
- Oral form not used for pyelonephritis

## Key interactions

**Metoclopramide**
Lowers fosfomycin levels in blood and urine.

## What is monitored

- Symptoms after treatment; urine culture if they persist
- Stool pattern

## Administration and safety

- The sachet is always dissolved in water before drinking, never swallowed dry
- Usually given as a single dose

## Nursing care

- Explain that symptoms may take a few days to settle
- Teach to report fever, flank pain or blood in the urine
- Ask about allergies

## Pregnancy and breastfeeding

Crosses the placenta; animal studies showed no birth defects.

## Memory aid

«Fosfo locks the front door»: it blocks MurA, the very first step of the wall.

## Test yourself

Think of the answer, then tap the question to see it.

## Which enzyme does fosfomycin block?

MurA, the enolpyruvyl transferase that starts peptidoglycan synthesis.

## How is oral fosfomycin taken?

Granules dissolved in water, usually as a single dose.

## Which drug lowers fosfomycin levels?

Metoclopramide.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/fosfomycin/)

## Related drugs

- [Nitrofurantoin](https://durgical.com/en/pharmacology/nitrofurantoin/)

## Related conditions

- [Urinary tract infection (acute cystitis)](https://durgical.com/en/conditions/urinary-tract-infection/)

[← Back to the class: Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - FOSFOMYCIN TROMETHAMINE granule, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=36bca22f-49ea-42ce-926b-035c42eb6038) (DailyMed (U.S. National Library of Medicine), 2026); [Fosfomycin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a697008.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=fosfomycin) (World Health Organization, 2025); [STRUCTURE OF UDP-N-ACETYLGLUCOSAMINE ENOLPYRUVYL TRANSFERASE](https://www.rcsb.org/structure/1UAE) (RCSB Protein Data Bank, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/fosfomycin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/fosfomycin/