Monurol (Fosfomycin) – Oral

What Is Monurol?

Monurol (fosfomycin) is an oral prescription drug used to treat urinary tract infections (UTIs) caused by certain bacteria. It is available as a powder packet that is dissolved in water.

Monurol is a broad-spectrum antibiotic. Broad-spectrum antibiotics work against a variety of bacteria. Monurol works by killing and stopping bacterial growth.

Drug Facts

Generic Name: Fosfomycin tromethamine

Brand Name(s): Monurol

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Broad-spectrum antibiotic

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Fosfomycin tromethamine

Dosage Form(s): Powder packet (to dissolve in water)

What Is Monurol Used For?

The Food and Drug Administration (FDA) approved Monurol (fosfomycin) to treat uncomplicated UTIs caused by susceptible strains of Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis). 

An uncomplicated UTI (sometimes also called acute cystitis) occurs in people with an otherwise normal urinary tract. When the infection occurs, the symptoms are confined to the urinary tract.

Monurol is not indicated to treat pyelonephritis (kidney infection) or perinephric abscess (a UTI complication).

How to Take Monurol

If you are prescribed Monurol, read the label and the information leaflet that comes with your prescription. Consult your healthcare provider with any questions or concerns.

Take Monurol exactly as directed by your healthcare provider. It should be taken in a single dose, with or without food. Monurol comes as a powder, which must be mixed with water. Do not take it in its dry form.

To prepare Monurol, pour the entire contents of the single-dose packet into 4 ounces (one-half cup) of water. Do not use hot water. Stir to dissolve and drink immediately after the powder dissolves.

Symptoms should improve within two or three days after taking it. Contact your healthcare provider if symptoms worsen or do not improve by the fourth day or if you develop diarrhea, especially if it is watery and bloody. This type of diarrhea is antibiotic-associated and can occur during treatment or up to two or more months after stopping.


Store Monurol at room temperature (6877 degrees F). Keep out of reach and out of sight of children and pets.

How Long Does Monurol Take to Work?

Monurol is taken as one dose. It starts working within a few hours and stays in the bladder for several days. You should start to feel better in two or three days. Contact your healthcare provider if you feel worse or your symptoms do not improve by the fourth day.

What Are the Side Effects of Monurol?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at or 800-FDA-1088.

Like other medications, Monurol can cause side effects. Tell your healthcare provider about any side effects you experience while taking this medication.

Common Side Effects

The most common side effects of Monurol are:

Severe Side Effects

Call your healthcare provider immediately if you have serious side effects. Dial 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Hypersensitivity reaction or anaphylaxis: This is a potentially life-threatening condition whose symptoms include difficulty breathing, rash, hives, and swelling around the lips, tongue, and face.
  • Toxic megacolon: This is a life-threatening inflammation of the colon that may cause a rupture in severe cases.
  • Antibiotic-associated diarrhea: This is an infection of the large intestine that's also known as C. diff–associated diarrhea. 

Long-Term Side Effects

Because Monurol is taken as a single dose, long-term side complications are rare. However, some side effects can occur as a delayed response.

Mild long-term side effects may include:

  • Back pain
  • Menstrual cramps
  • Sore throat
  • Weakness
  • Appetite loss
  • Flu
  • Infection
  • Numbness and tingling

Moderate long-term side effects may include:

  • Vaginitis
  • Constipation
  • Increased liver enzyme levels
  • Jaundice (yellowing of the skin and whites of the eyes, which can be a sign of infection or liver disease)
  • Swollen lymph nodes
  • Superinfection (a second infection on top of the first infection)
  • C. diff–associated diarrhea

Severe long-term side effects may include:

  • Toxic megacolon
  • C. diff–associated diarrhea
  • Hepatic necrosis (liver injury)
  • Optic neuritis (inflammation of the optic nerve, which can affect vision)
  • Hearing loss
  • Aplastic anemia (the body stops making enough new blood cells)

Report Side Effects

Monurol may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Monurol Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (powder for solution):
    • For treatment of bladder infection:
      • Adults—3 grams (one packet) dissolved in water taken one time.
      • Teenagers 13 to 17 years of age—Dose must be determined by your doctor.
      • Children 12 years of age and below—Use and dose must be determined by your doctor.


Certain factors may affect how you take Monurol. For example, you may need to use caution when taking it if you are 65 years or older. Because it is given in a single dose, no specific dose adjustments are needed. However, antibiotic use can cause diarrhea, secondary infections, and other side effects in this population.

Consult your healthcare provider for medical advice before using Monurol if you are pregnant, plan to become pregnant, or breastfeeding.

Missed Dose

Monurol is taken as a single dose, so you don't need to worry about missing doses.

Overdose: What Happens If I Take Too Much Monurol?

Since Monurol is given in a single-dose packet, it would be difficult to overdose on it. However, taking too much Monurol can cause hearing problems, a metallic taste in the mouth, and decreased taste perception. Contact your healthcare provider immediately if you've taken more Monurol than prescribed.

What Happens If I Overdose on Monurol?

If you think you or someone else may have overdosed on Monurol, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Monurol, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

If your symptoms do not improve within 2 or 3 days or if they become worse, check with your doctor.

This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop taking this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn't Take Monurol?

Monurol is not appropriate for everyone. You should not take this medication if you are allergic to fosfomycin or any of the inactive ingredients in Monurol.

Monurol may be prescribed with caution in some people only if the healthcare provider determines it is safe. This includes people with a recent history of antibiotic-associated diarrhea.

What Other Medications May Interact With Monurol?

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter (OTC) medications, vitamins, or herbal supplements. 

The blood-thinning drugs Coumadin and Jantoven (warfarin) can interact with Monurol. The combination may increase the risk of potentially life-threatening bleeding.

Examples of drugs that interact with Monurol, which may require different dosage adjustments, include:

  • Adlyxin (lixisenatide)
  • Urecholine (bethanechol)
  • Byetta, Bydureon (exenatide)
  • CellCept (mycophenolate mofetil)
  • Erythromycin
  • Levsin (hyoscyamine)
  • Motegrity (prucalopride)
  • Myfortic (mycophenolic sodium)
  • Reglan (metoclopramide)
  • Vyleesi (bremelanotide)

Because Monurol is given as a single dose, separating the times that the medications are taken may limit any adverse interaction. Ask your healthcare provider for help timing your medication.

Other drug interactions may occur with Monurol. Consult your healthcare provider for a complete list.

What Medications Are Similar?

Monurol contains the antibiotic fosfomycin. It is used to treat uncomplicated UTIs caused by certain bacteria. Examples of other oral antibiotics used to treat uncomplicated UTIs include:

For more complicated UTIs or those that are resistant to the above medications, a fluoroquinolone, such as Cipro (ciprofloxacin) or Levaquin (levofloxacin) may be used. Because of their side effects, fluoroquinolones generally are not used as a treatment of choice.

Sometimes, healthcare providers will also prescribe a medication such as phenazopyridine. This medication does not treat bacterial infections but may be used along with the antibiotic to help relieve symptoms until the infection clears.

It is also available over the counter in a lower dose as Azo Urinary Pain Relief. Phenazopyridine is known for causing a red to orange discoloration of body fluids, including urine, feces, and tears. Contact lenses should not be worn while taking this medication because discoloration or staining may occur.

The above is a list of drugs also prescribed for UTIs. It is not a list of drugs recommended to take with Monurol. Talk to your pharmacist or a healthcare provider if you have questions.

Frequently Asked Questions

  • What is Monurol used for?

    Monurol is used to treat uncomplicated UTIs caused by certain types of bacteria. It is taken as one dose.

  • How does Monurol work?

    Monurol works by killing bacteria and preventing bacteria from growing.

  • What drugs should not be taken with Monurol?

    Monurol interacts with certain drugs, but the interaction may be avoided by separating the timing of the drugs. Consult your healthcare provider regarding drug interactions. One possibly dangerous drug interaction is with the blood thinner warfarin, which can cause serious or life-threatening bleeding if combined with Monurol.

  • How long does it take for Monurol to work?

    Monurol is taken as a one-dose medication. Your symptoms should start to feel better in two to three days. However, if you feel worse or your symptoms do not improve by the fourth day, contact your healthcare provider for guidance.

  • What are the side effects of Monurol?

    Common side effects may include headache, dizziness, back pain, menstrual cramps, stuffy nose, and sore throat. Stomach problems such as nausea, diarrhea, and stomach pain can also occur frequently. You may also experience vaginal inflammation with itching, pain, and discharge symptoms.

  • How do I stop taking Monurol?

    Monurol is taken as a single dose. After the single dose, no more medication is required. Contact your healthcare provider if you do not feel better by the third day after taking Monurol.

How Can I Stay Healthy While Taking Monurol?

Before taking Monurol, discuss your medical history and all medications you take with your healthcare provider. When taking Monurol, follow your healthcare provider’s instructions for use and read the entire patient information leaflet that comes with your prescription.

Monurol starts working to kill bacteria within several hours after you take it, so you should feel relief within two to three days. If you do not feel better by the fourth day, contact your healthcare provider. Another antibiotic may be needed.

Here are some tips to help prevent UTIs in the future:

  • Always wipe from front to back after a bowel movement.
  • Change pads or tampons regularly during menstruation.
  • Avoid feminine deodorants and douches.
  • Urinate regularly and do not hold in your urine.
  • Avoid food and drinks that may irritate the bladder, such as alcohol, citrus fruits and juices, caffeine, and spicy foods.
  • Urinate before and after sex, and wash the genital area with warm water before having sex.
  • Wear cotton underwear, and avoid tight-fitting clothing, to help keep the area dry.

Talk to your healthcare provider about alternative forms of effective contraception if you use contraception that contributes to UTIs, such as spermicide.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. DailyMed. Label: Monurol - fosfomycin tromethamine powder.

  2. Kelly CP, Lamont JT. Patient education: antibiotic-associated diarrhea caused by Clostridioides difficile (beyond the basics). UpToDate.

  3. Prescribers’ Digital Reference. Fosfomycin tromethamine - drug summary.

  4. Epocrates. Monurol.

  5. Gupta K. Acute simple cystitis in females. UpToDate.

  6. DailyMed. Label: AZO Urinary Pain Relief Maximum Strength- phenazopyridine hydrochloride tablet.

  7. Pietrucha-Dilanchian P, Hooton TM. Diagnosis, treatment, and prevention of urinary tract infection. Microbiol Spectr. 2016;4(6). doi:10.1128/microbiolspec.UTI-0021-2015

By Karen Berger, PharmD
Karen Berger, PharmD, is a community pharmacist and medical writer/reviewer.