Dosing & Uses
Dosage Forms & Strengths
powder for reconstitution
- 3g/packet
Urinary Tract Infection (Acute Cystitis)
Acute cystitis caused by E. coli, E. faecalis
Acute uncomplicated cystitis: 3 g PO once
Multi-drug resistant UTI: 2-3 g PO every 2-3 days for 3 doses
Preparation: Dissolve 1 packet (3 g) in 3-4 oz water
Prostatitis (Off-label)
3 g PO q2-3 days or 3 g PO qDay for 1 week followed by 3 g q48hr for ≥6 weeks
Limitations of use
Not indicated for the treatment of perinephric abscess or pyelonephritis
Consider alternative agents if bacteriuria persists or reappears
Safety & efficacy not established
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (0)
Serious - Use Alternative (4)
- BCG vaccine live
fosfomycin decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
- cholera vaccine
fosfomycin, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.
- microbiota oral
fosfomycin decreases effects of microbiota oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Microbiota oral contains bacterial spores. Antibacterial agents may decrease efficacy if coadministered. Complete antibiotic regimens 2-4 days before initiating microbiota oral. .
- typhoid vaccine live
fosfomycin decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
Monitor Closely (9)
- bazedoxifene/conjugated estrogens
fosfomycin will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- conjugated estrogens
fosfomycin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- digoxin
fosfomycin will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.
- estradiol
fosfomycin will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- estrogens conjugated synthetic
fosfomycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- estropipate
fosfomycin will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- mestranol
fosfomycin will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- metoclopramide intranasal
metoclopramide intranasal will increase the level or effect of fosfomycin by Other (see comment). Use Caution/Monitor. Metoclopramide may decrease the absorption of fosfomycin. Monitor for reduced therapeutic effect of fosfomycin.
- sodium picosulfate/magnesium oxide/anhydrous citric acid
fosfomycin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
Minor (7)
- balsalazide
fosfomycin will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- biotin
fosfomycin will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- metoclopramide
metoclopramide decreases levels of fosfomycin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- pantothenic acid
fosfomycin will decrease the level or effect of pantothenic acid by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- pyridoxine
fosfomycin will decrease the level or effect of pyridoxine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- pyridoxine (Antidote)
fosfomycin will decrease the level or effect of pyridoxine (Antidote) by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- thiamine
fosfomycin will decrease the level or effect of thiamine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
Adverse Effects
1-10%
Anorexia
Diarrhea
Epigastric
Discomfort
Headache
Nausea
Rash
Vomiting
<1%
Dizziness
Drowsiness
Fatigue
Pruritus
Warnings
Contraindications
Hypersensitivity
Cautions
Hepatic injury, including hepatitis and steatosis reported; monitor liver function; effect is reversible upon discontinuation of drug
Prolonged use may result in bacterial or fungal superinfections, which may appear upt to two months postantibiotic treatment
Hypersensitivity reactions, including anaphylactic shock reported; discontinue use at first signs of hypersensitivity reactions and institute supportive measures
Pregnancy & Lactation
Pregnancy Category: B
Lactation: excreted in breast milk; not recommended
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
A phosphoric acid derivative that inactivates the enzyme pyruvyl transferase, which in turn inhibits bacterial wall synthesis and results in bactericidal effects
Absorption
Rapidly absorbed
Bioavailability: 37% (fasting); 30% (with food)
Time to peak: 2 hr (serum)
Distribution:
Vd: 90-180 L; high concentrations in urine; well into other tissues; crosses maximally into CSF with inflamed meninges
Elimination
Half-life: 3-8 hr (Normal renal function); 50 hr (CrCl <10 mL/min)
Excretion: urine (38% as unchanged drug); high urinary levels (100 mcg/mL) persist for >48 hr; feces (18%)
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
Monurol oral - | 3 gram miscellaneous | ![]() | |
fosfomycin tromethamine oral - | 3 gram miscellaneous | ![]() | |
fosfomycin tromethamine oral - | 3 gram miscellaneous | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
fosfomycin tromethamine oral
FOSFOMYCIN - ORAL
(FOS-foe-MYE-sin troe-METH-a-meen)
COMMON BRAND NAME(S): Monurol
USES: 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).
HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start taking fosfomycin. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth as directed by your doctor, usually 1 packet (sachet) as a single dose. Mix this drug with water before taking it. Pour the contents of 1 packet (sachet) into a half glass (4 ounces or 120 milliliters) of cold water and stir to dissolve. Do not use warm or hot water. Drink all of the mixture right away.Your symptoms should get better within 2 to 3 days. Tell your doctor if you do not get better after 3 days or if you get worse.
SIDE EFFECTS: Diarrhea, nausea, headache, vaginal discomfort, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: vision changes, unusual weakness.This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking fosfomycin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease.If you develop symptoms of a kidney infection (such as pain in your side or lower back area, fever, chills), contact your doctor right away. Your doctor may change your treatment.This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).This product may contain sugar and/or aspartame. Caution is advised if you have diabetes, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.Fosfomycin may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using fosfomycin before having any immunizations/vaccinations.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This drug passes into breast milk in small amounts, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: metoclopramide, probenecid.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: hearing loss, metallic taste.
NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.Lab and/or medical tests (such as urine culture) may be done while you are taking this medication. Keep all medical and lab appointments.
MISSED DOSE: Not applicable.
STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised October 2021. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This 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 for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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