NDC 82036-4274 Fosfomycin Tromethamine

Fosfomycin Tromethamine

NDC Product Code 82036-4274

NDC CODE: 82036-4274

Proprietary Name: Fosfomycin Tromethamine What is the Proprietary Name?
The proprietary name also known as the trade name is the name of the product chosen by the medication labeler for marketing purposes.

Non-Proprietary Name: Fosfomycin Tromethamine What is the Non-Proprietary Name?
The non-proprietary name is sometimes called the generic name. The generic name usually includes the active ingredient(s) of the product.

Drug Use Information

Drug Use Information
The drug use information is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate. This information is not individual medical advice and does not substitute for the advice of a health care professional. Always ask a health care professional for complete information about this product and your specific health needs.

  • This medication is an antibiotic used to treat bladder infections (such as acute cystitis or lower urinary tract infections) in women. It works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections. Fosfomycin should not be used to treat infections outside the bladder (such as kidney infections).

NDC Code Structure

NDC 82036-4274-1

Package Description: 1 DOSE PACK in 1 CARTON > 1 POWDER in 1 DOSE PACK

NDC 82036-4274-8

Package Description: 1 POWDER in 1 PACKET

NDC Product Information

Fosfomycin Tromethamine with NDC 82036-4274 is a a human prescription drug product labeled by Zambon Usa, Ltd. The generic name of Fosfomycin Tromethamine is fosfomycin tromethamine. The product's dosage form is powder and is administered via oral form.

Dosage Form: Powder - An intimate mixture of dry, finely divided drugs and/or chemicals that may be intended for internal or external use.

Product Type: Human Prescription Drug What kind of product is this?
Indicates the type of product, such as Human Prescription Drug or Human Over the Counter Drug. This data element matches the “Document Type” field of the Structured Product Listing.

Fosfomycin Tromethamine Active Ingredient(s)

What is the Active Ingredient(s) List?
This is the active ingredient list. Each ingredient name is the preferred term of the UNII code submitted.

Inactive Ingredient(s)

About the Inactive Ingredient(s)
The inactive ingredients are all the component of a medicinal product OTHER than the active ingredient(s). The acronym "UNII" stands for “Unique Ingredient Identifier” and is used to identify each inactive ingredient present in a product.

  • SUCROSE (UNII: C151H8M554)

Administration Route(s)

What are the Administration Route(s)?
The translation of the route code submitted by the firm, indicating route of administration.

  • Oral - Administration to or by way of the mouth.

Product Labeler Information

What is the Labeler Name?
Name of Company corresponding to the labeler code segment of the Product NDC.

Labeler Name: Zambon Usa, Ltd
Labeler Code: 82036
FDA Application Number: NDA050717 What is the FDA Application Number?
This corresponds to the NDA, ANDA, or BLA number reported by the labeler for products which have the corresponding Marketing Category designated. If the designated Marketing Category is OTC Monograph Final or OTC Monograph Not Final, then the Application number will be the CFR citation corresponding to the appropriate Monograph (e.g. “part 341”). For unapproved drugs, this field will be null.

Marketing Category: NDA AUTHORIZED GENERIC - A product marketed as a “generic” drug under an approved New Drug Application (NDA), rather than an Abbreviated New Drug Application (ANDA),. What is the Marketing Category?
Product types are broken down into several potential Marketing Categories, such as NDA/ANDA/BLA, OTC Monograph, or Unapproved Drug. One and only one Marketing Category may be chosen for a product, not all marketing categories are available to all product types. Currently, only final marketed product categories are included. The complete list of codes and translations can be found at www.fda.gov/edrls under Structured Product Labeling Resources.

Start Marketing Date: 08-25-2021 What is the Start Marketing Date?
This is the date that the labeler indicates was the start of its marketing of the drug product.

Listing Expiration Date: 12-31-2022 What is the Listing Expiration Date?
This is the date when the listing record will expire if not updated or certified by the product labeler.

Exclude Flag: N - NO What is the NDC Exclude Flag?
This field indicates whether the product has been removed/excluded from the NDC Directory for failure to respond to FDA"s requests for correction to deficient or non-compliant submissions ("Y"), or because the listing certification is expired ("E"), or because the listing data was inactivated by FDA ("I"). Values = "Y", "N", "E", or "I".

* Please review the disclaimer below.

Fosfomycin Tromethamine Product Labeling Information

The product labeling information includes all published material associated to a drug. Product labeling documents include information like generic names, active ingredients, ingredient strength dosage, routes of administration, appearance, usage, warnings, inactive ingredients, etc.

Product Labeling Index


Fosfomycin tromethamine granules for oral solution contains fosfomycin tromethamine, a synthetic, broad spectrum, bactericidal antibiotic for oral administration. It is available as a single-dose sachet which contains white granules consisting of 5.631 grams of fosfomycin tromethamine (equivalent to 3 grams of fosfomycin), and the following inactive ingredients: mandarin flavor, orange flavor, saccharin, and sucrose. The contents of the sachet must be dissolved in water. Fosfomycin tromethamine, a phosphonic acid derivative, is available as (1
S)-(1,2-epoxypropyl)phosphonic acid, compound with 2-amino-2-(hydroxymethyl)-1,3-propanediol (1:1). It is a white granular compound with a molecular weight of 259.2. Its empirical formula is C
3, and its chemical structure is as follows:

Clinical Pharmacology

Absorption: Fosfomycin tromethamine is rapidly absorbed following oral administration and converted to the free acid, fosfomycin. Absolute oral bioavailability under fasting conditions is 37%. After a single 3-gram dose of fosfomycin tromethamine, the mean (± 1 SD) maximum serum concentration (C
max) achieved was 26.1 (± 9.1) mcg/mL within 2 hours. The oral bioavailability of fosfomycin is reduced to 30% under fed conditions. Following a single 3-gram oral dose of fosfomycin tromethamine with a high-fat meal, the mean C
max achieved was 17.6 (± 4.4) mcg/mL within 4 hours.
Cimetidine does not affect the pharmacokinetics of fosfomycin when coadministered with fosfomycin tromethamine. Metoclopramide lowers the serum concentrations and urinary excretion of fosfomycin when coadministered with fosfomycin tromethamine. (See
PRECAUTIONS, Drug Interactions.)
Distribution: The mean apparent steady-state volume of distribution (V
ss) is 136.1 (±44.1) L following oral administration of fosfomycin tromethamine. Fosfomycin is not bound to plasma proteins.
Fosfomycin is distributed to the kidneys, bladder wall, prostate, and seminal vesicles. Following a 50 mg/kg dose of fosfomycin to patients undergoing urological surgery for bladder carcinoma, the mean concentration of fosfomycin in the bladder, taken at a distance from the neoplastic site, was 18.0 mcg per gram of tissue at 3 hours after dosing. Fosfomycin has been shown to cross the placental barrier in animals and man.Excretion: Fosfomycin is excreted unchanged in both urine and feces. Following oral administration of fosfomycin tromethamine, the mean total body clearance (CL
TB) and mean renal clearance (CL
R) of fosfomycin were 16.9 (± 3.5) L/hr and 6.3 (± 1.7) L/hr, respectively. Approximately 38% of a 3-gram dose of fosfomycin tromethamine is recovered from urine, and 18% is recovered from feces. Following intravenous administration, the mean CL
TB and mean CL
R of fosfomycin were 6.1 (±1.0) L/hr and 5.5 (± 1.2) L/hr, respectively.
A mean urine fosfomycin concentration of 706 (± 466) mcg/mL was attained within 2-4 hours after a single oral 3-gm dose of fosfomycin tromethamine under fasting conditions. The mean urinary concentration of fosfomycin was 10 mcg/mL in samples collected 72-84 hours following a single oral dose of fosfomycin tromethamine.Following a 3-gram dose of fosfomycin tromethamine administered with a high fat meal, a mean urine fosfomycin concentration of 537 (± 252) mcg/mL was attained within 6-8 hours. Although the rate of urinary excretion of fosfomycin was reduced under fed conditions, the cumulative amount of fosfomycin excreted in the urine was the same, 1118 (± 201) mg (fed) vs. 1140 mg (± 238) (fasting). Further, urinary concentrations equal to or greater than 100 mcg/mL were maintained for the same duration, 26 hours, indicating that fosfomycin tromethamine can be taken without regard to food.Following oral administration of fosfomycin tromethamine, the mean half-life for elimination (t
1/2) is 5.7 (± 2.8) hours.
Special Populations:Geriatric: Based on limited data regarding 24-hour urinary drug concentrations, no differences in urinary excretion of fosfomycin have been observed in elderly subjects. No dosage adjustment is necessary in the elderly.
Gender: There are no gender differences in the pharmacokinetics of fosfomycin.
Renal Insufficiency: In 5 anuric patients undergoing hemodialysis, the t
1/2 of fosfomycin during hemodialysis was 40 hours. In patients with varying degrees of renal impairment (creatinine clearances varying from 54 mL/min to 7 mL/min), the t
1/2 of fosfomycin increased from 11 hours to 50 hours. The percent of fosfomycin recovered in urine decreased from 32% to 11% indicating that renal impairment significantly decreases the excretion of fosfomycin.
MicrobiologyFosfomycin (the active component of fosfomycin tromethamine) has
in vitro activity against a broad range of gram-positive and gram-negative aerobic microorganisms which are associated with uncomplicated urinary tract infections. Fosfomycin is bactericidal in urine at therapeutic doses. The bactericidal action of fosfomycin is due to its inactivation of the enzyme enolpyruvyl transferase, thereby irreversibly blocking the condensation of uridine diphosphate-N-acetylglucosamine with p-enolpyruvate, one of the first steps in bacterial cell wall synthesis. It also reduces adherence of bacteria to uroepithelial cells.
There is generally no cross-resistance between fosfomycin and other classes of antibacterial agents such as beta-lactams and aminoglycosides.Fosfomycin has been shown to be active against most strains of the following microorganisms, both
in vitro and in clinical infections as described in the
Aerobic gram-positive microorganismsEnterococcus faecalisAerobic gram-negative microorganismsEscherichia coliThe following
in vitro data are available,
but theirclinical significance is unknown.Fosfomycin exhibits
in vitro minimum inhibitory concentrations (MIC’s) of 64 mcg/mL or less against most (≥ 90%) strains of the following microorganisms; however, the safety and effectiveness of fosfomycin in treating clinical infections due to these microorganisms has not been established in adequate and well-controlled clinical trials:
Aerobic gram-positive microorganismsEnterococcus faeciumAerobic gram-negative microorganismsCitrobacter diversusCitrobacter freundiiEnterobacter aerogenesKlebsiella oxytocaKlebsiella pneuomoniaeProteus mirabilisProteus vulgarisSerratia marcescensSUSCEPTIBILITY TESTINGDilution Techniques:Quantitative methods are used to determine minimum inhibitory concentrations (MIC’s). These MIC’s provide estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure uses a standardized agar dilution method
1 or equivalent with standardized inoculum concentrations and standardized concentrations of fosfomycin tromethamine (in terms of fosfomycin base content) powder supplemented with 25 mcg/mL of glucose-6-phosphate.
BROTH DILUTION METHODS SHOULDNOT BE USED TO TEST SUSCEPTIBILITY TO FOSFOMYCIN. The MIC values obtained should be interpreted according to the following criteria:
MIC (mcg/mL)Interpretation≤ 64Susceptible (S)128Intermediate (I)≥ 256Resistant (R)A report of “susceptible” indicates that the pathogen is likely to be inhibited by usually achievable concentrations of the antimicrobial compound in the urine. A report of “intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “resistant” indicates that usually achievable concentrations of the antimicrobial compound in the urine are unlikely to be inhibitory and that other therapy should be selected.Standardized susceptibility test procedures require the use of laboratory control microorganisms. Standard fosfomycin tromethamine powder should provide the following MIC values for agar dilution testing in media containing 25 mcg/mL of glucose-6-phosphate.
[Broth dilution testing should not be performed].MicroorganismMIC (mcg/mL)Enterococcus faecalis ATCC 29212
32-128Escherichia coli ATCC 25922
0.5-2Pseudomonas aeruginosa ATCC 27853
2-8Staphylococcus aureus ATCC 29213
0.5-4Diffusion Techniques:Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial agents. One such standardized procedure
2 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 200-mcg fosfomycin and 50-mcg of glucose-6-phosphate to test the susceptibility of microorganisms to fosfomycin.
Reports from the laboratory providing results of the standard single-disk susceptibility tests with disks containing 200-mcg of fosfomycin and 50-mcg of glucose-6-phosphate should be interpreted according to the following criteria:Zone Diameter (mm)Interpretation≥ 16Susceptible (S)13-15Intermediate (I)≤ 12Resistant (R)Interpretation should be stated as above for results using dilution techniques. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for fosfomycin.As with standardized dilution techniques, diffusion methods require use of laboratory control microorganisms that are used to control the technical aspects of the laboratory procedures. For the diffusion technique, the 200-mcg fosfomycin disk with the 50-mcg of glucose-6-phosphate should provide the following zone diameters in these laboratory quality control strains:MicroorganismZone Diameter (mm)Escherichia coli ATCC 25922
22-30Staphylococcus aureus ATCC 25923

Indications And Usage

Fosfomycin tromethamine 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 is not indicated for the treatment of pyelonephritis or perinephric abscess.
If persistence or reappearance of bacteriuria occurs after treatment with fosfomycin tromethamine, other therapeutic agents should be selected. (See


Fosfomycin tromethamine is contraindicated in patients with known hypersensitivity to the drug.


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.


Do not use more than one single dose of fosfomycin tromethamine to treat a single episode of acute cystitis. Repeated daily doses of fosfomycin tromethamine did not improve the clinical success or microbiological eradication rates compared to single dose therapy, but did increase the incidence of adverse events. Urine specimens for culture and susceptibility testing should be obtained before and after completion of therapy.

Information For Patients

  • Patients should be informed:That fosfomycin tromethamine can be taken with or without food.That their symptoms should improve in two to three days after taking fosfomycin tromethamine; if not improved, the patient should contact her health care provider.Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.

Fosfomycin TromethamineGranules for oral solution(equivalent to 3 grams of fosfomycin)Information for patients After taking fosfomycin tromethaminegranules for oral solutionyou should see improvement in your symptomsin 2 to 3 days.If your symptoms do not improve by the fourth day, you should contact your healthcare professional.2This booklet provides information on fosfomycin tromethamine granules for oral solution, the medication your doctor has prescribed for your bladder infection (acute cystitis), as well as background on the infection itself. It is important to know that, although your therapy is completed when you take the single dose of fosfomycin tromethamine granules for oral solution, it may take 2 to 3 days for symptoms to improve. If your symptoms do not improve by the fourth day, you should contact your healthcare professional.3What is fosfomycin tromethamine granules for oral solution for?Fosfomycin tromethamine granules for oral solution is for the treatment of acute cystitis in women. Acute cystitis, also known as bladder infection, is a type of uncomplicated urinary tract infection. Acute cystitis is caused by bacteria entering your bladder (which is normally bacteria free) resulting in irritation to your bladder lining. Fosfomycin tromethamine granules for oral solution is a bladder-specific antibiotic prescribed to kill the bacteria causing your infection. As the bacteria die, your bladder lining begins to heal.4How does fosfomycin tromethamine granules for oral solution work? Fosfomycin tromethamine granules for oral solution starts working to kill bacteria within hours after taking it. Although you only take fosfomycin tromethamine granules for oral solution once, fosfomycin tromethamine granules for oral solution is designed to stay in your bladder for more than 3 days, continuing to kill the bacteria. Therefore, after taking fosfomycin tromethamine granules for oral solution, you should see improvement in your symptoms in 2 to 3 days. If your symptoms do not improve by the fourth day, you should contact your healthcare professional.5What is in the sachet (packet)?The sachet packet contains white granules of fosfomycin tromethamine granules for oral solution (fosfomycin tromethamine), an antibiotic, along with a small amount of sweetener (saccharin and sucrose) and orange and mandarin flavoring.6Can I take fosfomycin tromethamine granules for oral solution if I am pregnant or breast-feeding?Adequate and well-controlled studies involving the use of fosfomycin tromethamine granules for oral solution in pregnant and breast-feeding women have not been conducted. If your physician feels it is clearly needed, fosfomycin tromethamine granules for oral solution can be taken. Please inform your healthcare provider if you know you are pregnant or are breast-feeding.7How do I take fosfomycin tromethamine granules for oral solution?1. Empty entire contents of fosfomycin tromethamine granules for oral solution sachet into 3 to 4 ounces of water (½ cup), and stir to dissolve. Do not use hot water.2. Take immediately after dissolving in water, making sure to drink complete contents of glass.8Is this all I need to do?Yes. One sachet of fosfomycin tromethamine granules for oral solution is a complete therapy for treating your bladder infection. The medicine in fosfomycin tromethamine granules for oral solution goes directly to your bladder and stays there for several days to kill the bacteria causing your infection.9Does fosfomycin tromethamine granules for oral solution always work?No antibiotic works 100% of the time. In controlled clinical trials, using strict criteria for evaluation, approximately three quarters of patients were cured after single dose treatment with fosfomycin tromethamine granules for oral solution. This cure rate was equivalent to that for patients treated with Macrobid®**, and somewhat lower than for patients treated with Cipro®† and with Bactrim®††.10Will I experience side effects?Because fosfomycin tromethamine granules for oral solution goes right to the site of your infection, side effects from the drug are uncommon. Less than 1 patient in 10 (9.0%) taking fosfomycin tromethamine granules for oral solution may experience diarrhea. Other infrequently seen side effects are vaginitis (5.5%), nausea (4.1%), headache (3.9%), dizziness (1.3%), tiredness (1.1%), and indigestion (1.1%).11What if I am allergic to fosfomycin tromethamine granules for oral solution?Fosfomycin tromethamine granules for oral solution is not related to penicillin or other antibiotics that commonly cause allergic reactions. If you have a history of allergy to antibiotics, you should be able to take fosfomycin tromethamine granules for oral solution on your doctor’s advice.12What about taking fosfomycin tromethamine granules for oral solution with other drugs?Fosfomycin tromethamine granules for oral solution has very few interactions with other drugs. If you are currently taking a gastrointestinal drug called Reglan®* (metoclopramide hydrochloride), you should not take fosfomycin tromethamine granules for oral solution unless you have discussed this with your doctor.13Some other precautions:Do not take this or any other medication if it was prescribed for someone else.KEEP FOSFOMYCIN TROMETHAMINE GRANULES FOR ORAL SOLUTION OUT OF THE REACH OF CHILDREN.Do not use after the expiration date printed on the box.*Reglan is a registered trademark of A. H. Robins Company.

**Macrobid is a registered trademark of Procter & Gamble.

†Cipro is a registered trademark of Bayer Corporation.

††Bactrim is a registered trademark of Roche Pharmaceuticals.
14What is acute cystitis?Acute cystitis is the common name for uncomplicated urinary tract infection. It is an infection of the urinary bladder that causes the bladder lining to become inflamed or irritated.15What causes acute cystitis?Acute cystitis is usually caused by bacteria that enter the bladder. Bacteria can travel from the anal area to collect in the vagina and then enter the urethra to finally reach the bladder.16What are the usual symptoms?Typical symptoms include frequent urination, painful urination, and a bladder that never feels totally empty. Other symptoms include pain in the pubic area.17Is acute cystitis dangerous?Normally it is not, unless the bacteria in the urine causing it have traveled upward to infect the kidneys. Your doctor has prescribed fosfomycin tromethamine granules for oral solution to prevent this from occurring.18How is acute cystitis diagnosed and treated?Acute cystitis is diagnosed on the basis of your symptoms and/or a urine culture to identify the responsible bacteria. It is most often treated with antibiotics.19Is there something I can take to relieve my pain?There are medications available in addition to your primary therapy, fosfomycin tromethamine granules for oral solution, that your healthcare provider can recommend. Talk to your healthcare provider about additional medication.20Is there anything I can do to avoid acute cystitis?Bladder infections that occur repeatedly in women are often associated with sexual activity and/or certain methods of contraception. Urinating immediately and completely after intercourse can help flush out bacteria that may have been accidentally forced into the urethra. Women who use a diaphragm with spermicidal jelly or use spermicidal foam with a condom should consider another form of contraception if they continue to experience infections.21You should also wipe from front to back to avoid contaminating the urethral entrance with bacteria from the bowels. You should discuss these and other ways to prevent bladder infections with your healthcare provider.22DO NOT TAKE THIS OR ANY MEDICATION IF IT WAS PRESCRIBED FOR SOMEONE ELSE.FOSFOMYCIN TROMETHAMINE GRANULES FOR ORAL SOLUTION IS NOT RECOMMENDED FOR PATIENTS UNDER 18 YEARS OF AGE.KEEP FOSFOMYCIN TROMETHAMINE GRANULES FOR ORAL SOLUTION OUT OF REACH OF CHILDREN.DO NOT USE AFTER EXPIRATION DATE.Manufactured by:
Zambon Switzerland Ltd.

A Subsidiary of Zambon S.p.A.

Via Industria 13

6814 Cadempino, Switzerland
Distributed by:Zambon USA Ltd.

One Broadway, 14th Floor, Cambridge MA 02142
TM and its designs are trademarks of Zambon S.p.A.
Made in SwitzerlandZambon USA Ltd.06/2021

Drug Interactions

Metoclopramide: When coadministered with fosfomycin tromethamine, metoclopramide, a drug which increases gastrointestinal motility, lowers the serum concentration and urinary excretion of fosfomycin. Other drugs that increase gastrointestinal motility may produce similar effects.
Cimetidine: Cimetidine does not affect the pharmacokinetics of fosfomycin when coadministered with fosfomycin tromethamine.

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Long term carcinogenicity studies in rodents have not been conducted because fosfomycin tromethamine is intended for single dose treatment in humans. Fosfomycin tromethamine was not mutagenic or genotoxic in the
in vitro Ames’ bacterial reversion test, in cultured human lymphocytes, in Chinese hamster V79 cells, and the
in vivo mouse micronucleus assay. Fosfomycin tromethamine did not affect fertility or reproductive performance in male and female rats.


Teratogenic EffectsWhen 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.

Nursing Mothers

It is not known whether fosfomycin tromethamine is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from fosfomycin tromethamine, a decision should be made whether to discontinue nursing or to not administer the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in children age 12 years and under have not been established in adequate and well-controlled studies.

Geriatric Use

Clinical studies of fosfomycin tromethamine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

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 PopulationsAdverseEventsFosfomycinN=1233NitrofurantoinN=374Trimethoprim/sulfamethoxazoleN=428CiprofoxacinN=455Diarrhea9. clinical trials, the most frequently reported adverse events occurring in > 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.

Post-Marketing Experience:

Serious adverse events from the marketing experience with fosfomycin tromethamine outside of the United States have been rarely reported and include: angioedema, aplastic anemia, asthma (exacerbation), cholestatic jaundice, hepatic necrosis, and toxic megacolon.Although causality has not been established, during post marketing surveillance, the following events have occurred in patients prescribed fosfomycin tromethamine: anaphylaxis and hearing loss.

Laboratory Changes:

Significant laboratory changes reported in U.S. clinical trials of fosfomycin tromethamine without regard to drug relationship include: increased eosinophil count, increased or decreased WBC count, increased bilirubin, increased SGPT, increased SGOT, increased alkaline phosphatase, decreased hematocrit, decreased hemoglobin, increased and decreased platelet count. The changes were generally transient and were not clinically significant.


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 2-3 days after single dose administration. These doses represent 50-125 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.

Dosage And 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. Fosfomycin tromethamine may be taken with or without food.Fosfomycin tromethamine should not be taken in its dry form. Always mix fosfomycin tromethamine with water before ingesting. (See


Fosfomycin tromethamine should be taken orally. Pour the entire contents of a single-dose sachet of fosfomycin tromethamine into 3 to 4 ounces of water (1/2 cup) and stir to dissolve. Do not use hot water. Fosfomycin tromethamine should be taken immediately after dissolving in water.

How Supplied

Fosfomycin tromethamine granules for oral solution is available as a single-dose sachet containing the equivalent of 3 grams of fosfomycin.NDCSingle-dose sachet 82036-4274-8One unit carton 82036-4274-1Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F).Keep this and all drugs out of the reach of children.

Clinical Studies

In controlled, double-blind studies of acute cystitis performed in the United States, a single-dose of fosfomycin tromethamine was compared to three other oral antibiotics (See table below). The study population consisted of patients with symptoms and signs of acutecystitis of less than 4 days duration, no manifestations of upper tract infection (e.g., flank pain, chills, fever), no history of recurrent urinary tract infections (20% of patients in the clinical studies had a prior episode of acute cystitis within the preceding year), no known structural abnormalities, no clinical or laboratory evidence of hepatic dysfunction, and no known or suspected CNS disorders, such as epilepsy, or other factors which would predispose to seizures. In these studies, the following clinical success (resolution of symptoms) and microbiologic eradication rates were obtained.Treatment ArmTreatmentDuration(days)Microbiologic Eradication RateClinical SuccessRateOutcome (based on difference inmicrobiologic eradication rates 5-11 days post therapy)5-11 days post therapyStudy day 12-21Fosfomycin1630/771






Fosfomycin inferior to ciprofloxacinTrimethoprim/




Fosfomycin inferior to trimethoprim/




Fosfomycin equivalent to

PathogenFosfomycin 3 gram singledoseCiprofloxacin 250 mg bid x 7 daysTrimethoprim/sulfamethoxazole 160 mg/800 mg bid x 10 daysNitrofurantoin 100 mg bid x 7 daysE. coli509/644 (79%)184/187



E. faecalis10/10 (100%)0/04/4




1. National Committee for Clinical Laboratory Standards, Methods for Dilution. Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically – Third Edition; Approved Standard NCCLS Document M7-A3, Vol. 13, No. 25 NCCLS, Villanova, PA, December, 1993.2. National Committee for Clinical Laboratory Standards, Performance Standard for Antimicrobial Disk Susceptibility Tests – Fifth Edition; Approved Standard NCCLS Document M2-A5, Vol. 13, No. 24 NCCLS, Villanova, PA, December, 1993.Manufactured by:

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