pharmacopeia
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/api/v1/drug/fosfomycin

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Enzyme Inhibitors.

Enzyme

Indications

Sourced from openFDA
  • & USAGE Fosfomycin tromethamine granules for oral solution is indicated only for the treatment of uncomplicated urinary tract infections (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis . Fosfomycin tromethamine granules for oral solution is not indicated for the treatment of pyelonephritis or perinephric abscess.ICD-10: N39.0

Contraindications

Sourced from openFDA
  • Fosfomycin tromethamine is contraindicated in patients with known hypersensitivity to the drug.contraindicated

Dosage & administration

Sourced from openFDA

DOSAGE & ADMINISTRATION The recommended dosage for women 18 years of age and older for uncomplicated urinary tract infection (acute cystitis) is one sachet of fosfomycin tromethamine granules for oral solution. Fosfomycin tromethamine granules for oral solution may be taken with or without food. Fosfomycin tromethamine granules for oral solution should not be taken in its dry form. Always mix fosfomycin tromethamine granules for oral solution with water before ingesting. (See PREPARATION section.) PREPARATION Fosfomycin tromethamine granules for oral solution should be taken orally. Pour the entire contents of a single-dose sachet of fosfomycin tromethamine granules for oral solution into 3 to 4 ounces of water (1/2 cup) and stir to dissolve. Do not use hot water. Fosfomycin tromethamine granules for oral solution should be taken immediately after dissolving in water.

Warnings & precautions

Sourced from openFDA

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including fosfomycin tromethamine, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated.

Adverse reactions

Sourced from openFDA

Clinical Trials: In clinical studies, drug related adverse events which were reported in greater than 1% of the fosfomycin-treated study population are listed below: Drug-Related Adverse Events (%) in Fosfomycin and Comparator Populations Adverse Events Fosfomycin N=1233 Nitrofurantoin N=374 Trimethoprim/ sulfamethoxazole N=428 Ciprofoxacin N=455 Diarrhea 9.0 6.4 2.3 3.1 Vaginitis 5.5 5.3 4.7 6.3 Nausea 4.1 7.2 8.6 3.4 Headache 3.9 5.9 5.4 3.4 Dizziness 1.3 1.9 2.3 2.2 Asthenia 1.1 0.3 0.5 0.0 Dyspepsia 1.1 2.1 0.7 1.1 In clinical trials, the most frequently reported adverse events occurring in greater than 1% of the study population regardless of drug relationship were: diarrhea 10.4%, headache 10.3%, vaginitis 7.6%, nausea 5.2%, rhinitis 4.5%, back pain 3.0%, dysmenorrheal 2.6%, pharyngitis 2.5%, dizziness 2.3%, abdominal pain 2.2%, pain 2.2%, dyspepsia 1.8%, asthenia 1.7%, and rash 1.4%. The following adverse events occurred in clinical trials at a rate of less than 1%, regardless of drug relationship: abnormal stools, anorexia, constipation, dry mouth, dysuria, ear disorder, fever, flatulence, flu syndrome, hematuria, infection, insomnia, lymphadenopathy, menstrual disorder, migraine, myalgia, nervousness, paresthesia, pruritus, SGPT increased, skin disorder, somnolence, and vomiting. One patient developed unilateral optic neuritis, an event considered possibly related to fosfomycin tromethamine therapy.

Use in specific populations

Sourced from openFDA

PREGNANCY Teratogenic Effects When administered intramuscularly as the sodium salt at a dose of 1 gram to pregnant women, fosfomycin crosses the placental barrier. Fosfomycin tromethamine crosses the placental barrier of rats; it does not produce teratogenic effects in pregnant rats at dosages as high as 1000 mg/kg/day (approximately 9 and 1.4 times the human dose based on body weight and mg/m 2 , respectively). When administered to pregnant female rabbits at dosages as high as 1000 mg/kg/day (approximately 9 and 2.7 times the human dose based on body weight and mg/m 2 , respectively), fetotoxicities were observed. However, these toxicities were seen at maternally toxic doses and were considered to be due to the sensitivity of the rabbit to changes in the intestinal microflora resulting from the antibiotic administration. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Overdosage

Sourced from openFDA

In acute toxicology studies, oral administration of high doses of fosfomycin tromethamine up to 5 g/kg were well-tolerated in mice and rats, produced transient and minor incidences of watery stools in rabbits, and produced diarrhea with anorexia in dogs occurring 2 to 3 days after single dose administration. These doses represent 50 to 125 times the human therapeutic dose. The following events have been observed in patients who have taken fosfomycin tromethamine in overdose: vestibular loss, impaired hearing, metallic taste, and general decline in taste perception. In the event of overdosage, treatment should be symptomatic and supportive.

Approval history

Sourced from openFDA
  • Oct 21, 2021ANDAANDA214554Alkem Labs Ltd
  • Jan 26, 2022ANDAANDA211881Cipla
  • Mar 25, 2024ANDAANDA216600Amneal
  • Jun 3, 2025ANDAANDA217187Precision Dose Inc
  • Oct 22, 2025NDANDA212271Meitheal
  • Nov 14, 2025ANDAANDA217608Aurobindo Pharma Ltd
  • Apr 9, 2026ANDAANDA217772Aucta

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
575 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Nausea579.9%
  2. 2Diarrhoea529.0%
  3. 3Dyspnoea518.9%
  4. 4Off Label Use518.9%
  5. 5Dizziness508.7%
  6. 6Urinary Tract Infection457.8%
  7. 7Fatigue417.1%
  8. 8Vomiting417.1%
  9. 9Asthenia295.0%
  10. 10Arthralgia284.9%
  11. 11Covid-19284.9%
  12. 12Headache284.9%
  13. 13Malaise274.7%
  14. 14Pain274.7%
  15. 15Cystitis244.2%

Literature

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Recent PubMed references pinned to Fosfomycin as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 90 ClinicalTrials.gov registrations naming Fosfomycin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Fosfomycin work?
Mechanism-of-action class: Enzyme Inhibitors.
What is Fosfomycin used for?
According to FDA labeling, Fosfomycin carries indications including: & USAGE Fosfomycin tromethamine granules for oral solution is indicated only for the treatment of uncomplicated urinary tract infections (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis . Fosfomycin tromethamine granules for oral solution is not indicated for the treatment of pyelonephritis or perinephric abscess.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Fosfomycin?
Fosfomycin is classified as Antiinfectives, Other antibacterials, Enzyme Inhibitors, Decreased Cell Wall Synthesis & Repair.
What are the brand names for Fosfomycin?
Fosfomycin is marketed under brand names including Contepo.
What are the contraindications for Fosfomycin?
Fosfomycin labeling lists contraindications including: Fosfomycin tromethamine is contraindicated in patients with known hypersensitivity to the drug.. Always consult the full prescribing information and a clinician.
Note. Data for fosfomycin is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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