Evigrade
DrugsCosmetic ingredientsCalculatorsInteractionsEvigrade SkinEvigrade Meds ↗
ConditionsJournalMethodologyPro for practitioners
ESRU

Fosfomycin

AEMPS

Other antibacterials

ATC code: J01XX01

Brand names: Fosfomicina Abamed, Monurol, Fosfomicina Cinfa, Fosfomicina Stada

Updated · Methodology

Indications

A

Uncomplicated acute cystitis in women

First line

First-line for uncomplicated acute cystitis in women per 2010 and Spanish SEMI 2022. Single 3 g oral dose of fosfomycin trometamol (Monurol) 2 hours before bedtime with an empty bladder. Covers E. coli (including some ESBL strains), Klebsiella, Proteus, Enterobacter. Efficacy 80–90%. Advantage over fluoroquinolones – lower resistance (E. coli to ciprofloxacin in Spain reaches 25–35%, to fosfomycin 2–5%).

Sources

  1. AEMPS: Ficha técnica de Fosfomicina (2024)
  2. EAU: EAU Guidelines on Urological Infections (2024)

ICD-10: N30.0 · ICD-11: GC00.0

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

F

Common cold

Not recommended

Fosfomycin tromethamine is prescribed as a broad-spectrum fallback in respiratory viral infections. 2024 AWaRe and 2024 confine fosfomycin to uncomplicated UTIs and outpatient bacteriuria prophylaxis in pregnancy. Use in upper respiratory infections, bronchitis or pneumonia is not indicated: oral fosfomycin achieves meaningful concentrations only in urine.

Sources

  1. AEMPS: Ficha técnica de Fosfomicina (2024)
  2. Cochrane (Hemila and Chalker): Vitamin C for preventing and treating the common cold (2013)

ICD-10: J00 · ICD-11: CA00

How to read tiers A–F
  • AStrong evidence – first or second line in international guidelines
  • BRecommended in selected cases
  • CStudy data contradict each other
  • DBenefit not proven, no documented harm
  • FDocumented harm, or risk without benefit

Mechanism of action

Phosphonic acid derivative, a bactericidal antibiotic with a unique mechanism. Inhibits the first step of bacterial cell wall synthesis via UDP-N-acetylglucosamine enolpyruvyl transferase (MurA). After a single 3 g oral dose (fosfomycin trometamol), it concentrates in urine, making it first-line for uncomplicated cystitis. In Spain, Monurol (Zambon) is the most-prescribed antibiotic for UTIs in primary care.

Safety

Contraindications

  • Fosfomycin hypersensitivity
  • Severe renal impairment (eGFR below 10 mL/min)
  • Age under 12 (for Monurol formulation)

Serious adverse effects

  • Anaphylaxis (very rare)
  • C. difficile colitis (rare – short course lowers risk)

Common adverse effects

  • Diarrhea
  • Nausea
  • Headache
  • Vaginitis
  • Rash

Pregnancy: can you take Fosfomycin?

AEMPS summary of product characteristics (section 4.6): safety data on fosfomycin in the first trimester of pregnancy are limited (n = 152) and so far show no signs of teratogenic potential. Fosfomycin crosses the placenta. Animal studies do not suggest direct or indirect harmful effects with respect to reproductive toxicity. Fosfomycin should be used in pregnancy only if strictly necessary.

Breastfeeding: can you take Fosfomycin?

Minimal milk excretion. Single dose during breastfeeding is safe.

Calculate RIDFull profile on NIH LactMed ↗

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Dissolve the sachet contents in a glass of water (not milk or juice) and drink on an empty stomach 2 hours before bedtime or 2–3 hours after a meal. Do not immediately void – the drug must accumulate. Effect develops within 24–48 hours; if symptoms persist, perform urine culture and reassess. In pregnant women with asymptomatic bacteriuria, same dose.

Drug interactions

Metoclopramide lowers urinary fosfomycin levels – separate dosing by at least 2 hours. Same caution for antacids and iron supplements. No clinically significant impact on oral contraceptives.
Label mentions5 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

  • MajorMetoclopramide
    «Metoclopramida: Se ha mostrado que la administración concomitante de metoclopramida reduce las concentraciones en suero y orina de fosfomicina y, por tanto, se debe evitar.»

    AEMPS, section 4.5 · Open on CIMA

  • anticoagulantesclass named in the label
    «Se han notificado numerosos casos de aumento de la actividad de los anticoagulantes orales en los pacientes que recibían tratamiento antibiótico. Los factores de riesgo son la presencia de…»

    AEMPS, section 4.5 · Open on CIMA

  • macrólidosclass named in the label
    «Se han notificado numerosos casos de aumento de la actividad de los anticoagulantes orales en los pacientes que recibían tratamiento antibiótico. Los factores de riesgo son la presencia de…»

    AEMPS, section 4.5 · Open on CIMA

  • Metoclopramide
    «Drug Interactions: Metoclopramide: When coadministered with fosfomycin tromethamine, metoclopramide, a drug which increases gastrointestinal motility, lowers the serum concentration and urinary…»

    FDA, section 7 · Open on DailyMed

  • quinolonasclass named in the label
    «Se han notificado numerosos casos de aumento de la actividad de los anticoagulantes orales en los pacientes que recibían tratamiento antibiótico. Los factores de riesgo son la presencia de…»

    AEMPS, section 4.5 · Open on CIMA

Check interaction with another drug

Opens the checker prefilled with this drug. Pick the second one from your regimen.

Open checker

Summary of a multi-drug list →

Medicine list: everything you take in one place →

Frequently asked

What is Fosfomycin used for?

Fosfomycin is evaluated for the following indications with varying evidence strength: Uncomplicated acute cystitis in women (evidence tier A), Common cold (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Fosfomycin?

Common side effects of Fosfomycin (≥ 1 in 100): Diarrhea, Nausea, Headache, Vaginitis, Rash. See the Safety section for uncommon and serious reactions.

Is Fosfomycin safe during pregnancy?

AEMPS summary of product characteristics (section 4.6): safety data on fosfomycin in the first trimester of pregnancy are limited (n = 152) and so far show no signs of teratogenic potential. Fosfomycin crosses the placenta. Animal studies do not suggest direct or indirect harmful effects with respect to reproductive toxicity. Fosfomycin should be used in pregnancy only if strictly necessary.

Is Fosfomycin compatible with breastfeeding?

Minimal milk excretion. Single dose during breastfeeding is safe.

Who should not take Fosfomycin?

Fosfomycin is contraindicated in: Fosfomycin hypersensitivity; Severe renal impairment (eGFR below 10 mL/min); Age under 12 (for Monurol formulation). Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

Other drugs in this group

Gentamicin, Levofloxacin, Linezolid, Meropenem, Metronidazole, Amoxicillin, Cefuroxime axetil, Co-trimoxazole