Monurol

Fosfomycin

Method of action: Antibacterial Broad Spectrum (Bactericidal), Bactericidal

Treatment option: Abscess, Infection, Acute Bacterial Cystitis, Fits, Infection Prophylaxis, Urethritis, Cystitis

Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Monurol

Quick Facts about Monurol

Property	Description
Active ingredient	Fosfomycin tromethamine
Form	Granules for Oral Solution (Single-dose sachet)
Pharmacological class	Antibiotic (Urinary Anti-infective)
General purpose	To eliminate susceptible bacterial pathogens
Origin	Synthetic (Phosphonic acid derivative)

What Type of Medicine is Monurol and How is it Classified?

Monurol is an antibiotic medication containing the active ingredient fosfomycin tromethamine (or fosfomycin trometamol), classified specifically as a urinary anti-infective. It belongs to the unique group of miscellaneous antibiotics.

The active substance, fosfomycin, is a synthetic compound derived from phosphonic acid. Its structural makeup is distinct from common antibiotic classes like beta-lactams, positioning it within a novel class of antibiotic. This structural difference minimizes the issue of cross-resistance, making Monurol a clinically recognized option for addressing bacterial strains that have developed resistance to more widely used antibiotics.

Composition and The Single-Dose Granule Form

The preparation is a single-ingredient product, composed of fosfomycin chemically linked to the salt tromethamine. The role of the tromethamine salt is critical for enhancing the drug's absorption after oral ingestion, a feature distinguishing this formulation.

Monurol is supplied as granules for oral solution in a distinctive single-dose sachet, a key factor separating it from traditional multi-day regimens. This form is designed for rapid dissolution in water, ensuring the delivery of a highly concentrated and sustained level of the active substance, fosfomycin, to the urinary tract.

What is the General Purpose of This Antibacterial?

The general purpose of Monurol is to serve as an effective anti-infective by combating susceptible bacterial pathogens through a powerful bactericidal effect. The unique action of fosfomycin involves the direct inhibition of bacterial cell wall synthesis. This early-stage mechanism blocks the enzyme enolpyruvyl transferase (MurA). This robust, targeted mechanism underpins the utility of Monurol in eliminating bacterial pathogens.

What side effects are possible with Monurol?

Possible Side Effects and Safety Information

This section describes the safety characteristics and adverse reactions of Monurol (fosfomycin tromethamine) as formally documented in government regulatory labeling.

Frequency-Classified Adverse Reactions

The officially listed adverse reactions are categorized by their estimated frequency, based on clinical data reported in regulatory documents.

Frequency Classification	Documented Adverse Reactions (Examples)	System-Organ Class Involved
Common (1 to 10 in 100)	Diarrhoea, Headache, Dizziness, Vulvovaginitis	Gastrointestinal, Nervous System, Infections
Uncommon (1 to 10 in 1,000)	Nausea, Abdominal pain, Rash, Fatigue	Gastrointestinal, Skin, General Disorders
Rare / Not Known	Angioedema, Anaphylactic shock	Immune System

Documented Serious Adverse Reactions and Safety Constraints

Regulatory sources define several serious, though rare, adverse reactions, including the possibility of severe systemic hypersensitivity reactions like anaphylactic shock and serious intestinal inflammation such as antibiotic-associated colitis (pseudomembranous colitis). These reactions may occur immediately following administration or, in the case of colitis, during or after treatment is concluded.

The official labeling outlines specific high-level safety constraints. The medicine is restricted from use in individuals with a known history of hypersensitivity to fosfomycin tromethamine or its components. Additionally, the drug is generally considered inappropriate for patients with severe renal impairment due to the reduced clearance of fosfomycin, which could lead to substance accumulation. The presence of specific excipients in the formulation, such as sucrose, also restricts use in individuals with conditions like hereditary fructose intolerance.

Overdose and Emergency Response

Overdose with Monurol (fosfomycin tromethamine) requires immediate attention as defined by official regulatory guidance. A suspected overdose is characterized by the potential presentation of specific clinical manifestations. These documented effects include vestibular loss, which is the loss of balance, and impaired hearing. Patients may also experience changes in sensory perception, such as a metallic taste and a general decline in taste perception (dysgeusia).

Other systemic signs reported in overdose scenarios are somnolence (drowsiness) and hypotonia (loss of muscle tone), alongside potential electrolyte disturbances. Regulatory information notes the potential for haematological effects such as thrombocytopenia.

Required Emergency Action

Regulatory documents state explicitly that when an overdosage is suspected, it is mandatory to contact a poison control center or emergency room at once. The patient must be monitored, particularly for plasma or serum electrolyte levels.

Official Management Measures

Treatment for overdosage is defined as symptomatic and supportive. No specific antidote is known or documented in the official prescribing information. Supportive procedures described include rehydration to promote urinary elimination of the substance. Official reports also indicate that fosfomycin is effectively cleared from the body by haemodialysis if clinically necessary.

Therapeutic Uses of Monurol

Main Uses of Monurol

Monurol is an antibiotic primarily utilized for the treatment of uncomplicated urinary tract infections (UTIs). Its specific application is centered on acute cystitis, which is an inflammation of the bladder typically caused by bacterial infiltration.

This medication is effective against a variety of bacteria that commonly cause these infections, including both Gram-positive and Gram-negative organisms. It works by interfering with the bacteria's ability to build a cell wall, ultimately leading to the elimination of the infection-causing pathogens.

Primary Indications

Acute Cystitis: The treatment of sudden-onset bladder infections in women.
Bacterial Targeting: Effective against common urinary pathogens such as Escherichia coli and Enterococcus faecalis.

Benefits and Clinical Advantages

The primary benefit of Monurol is its ability to reach high concentrations in the urine quickly and maintain those levels for a duration sufficient to clear the infection. Because the medication is concentrated specifically in the urinary tract, it targets the site of infection directly.

Key Therapeutic Benefits

Targeted Action: The active ingredient remains highly concentrated in the bladder, providing prolonged antibacterial activity where it is needed most.
Broad-Spectrum Activity: It provides coverage against multiple types of bacteria, including some strains that may be resistant to other common antibiotics.
Efficacy in Uncomplicated Cases: It is specifically designed to resolve symptoms and clear bacteria in cases where the infection is localized to the lower urinary tract and has not spread to the kidneys.

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Monurol

Official regulatory documents define specific populations who can and cannot use Monurol (fosfomycin tromethamine).

Eligibility Scope	Status Determined by Regulatory Label
Populations Allowed	Approved for adult women and female adolescents (typically 12 years and older) for the treatment of uncomplicated acute cystitis.
Contraindicated Populations	Patients with known hypersensitivity to fosfomycin or any excipients in the formulation. Patients with severe renal impairment (Creatinine Clearance <10 mL/min) or those undergoing haemodialysis.
Age-Related Rules	Not recommended for children under 12 years of age, as safety and efficacy for this use are not established. Use in older adults is permitted but requires caution due to the higher likelihood of decreased renal function.
Conditional Use	Pregnancy and Lactation: Use is not recommended unless the therapeutic benefit is officially determined to clearly outweigh the potential risk.
Condition-Specific Restrictions	Contraindicated in patients with hereditary problems like fructose intolerance or sucrase-isomaltase deficiency due to excipients (sucrose) in the sachet formulation.

Official regulatory statements establish that Monurol is only for the treatment of uncomplicated infections and is strictly prohibited for groups with severe non-eligibility factors, such as renal failure or known hypersensitivity. This structure limits the medicine's use to the population where its single-dose profile has been formally evaluated and approved.

What should I know about interactions with other medicines?

Monurol Interactions with other medicines and products

When taking Monurol (fosfomycin), it is important to be aware of interactions with other medicinal products, which can affect the concentration and effectiveness of the antibiotic.

Documented Pharmacokinetic Interaction

The primary interaction documented in regulatory information involves medications that increase gastrointestinal motility. Specifically, the drug Metoclopramide has been shown to lower the maximum concentration of fosfomycin in the blood and decrease its excretion in the urine when the two are taken together. This interaction is due to Metoclopramide accelerating the passage of Monurol through the digestive system, reducing the amount of the antibiotic that is absorbed. The same effect may occur with other drugs that similarly increase gastrointestinal movement.

Other Interacting Substances

In contrast, studies have shown that Cimetidine does not affect the pharmacokinetics of fosfomycin, meaning it does not change how the body absorbs or eliminates Monurol. Additionally, combining Monurol with live vaccines, such as the oral typhoid vaccine or cholera vaccine, is generally avoided due to the potential for the antibiotic to reduce the effectiveness of the vaccine.

Always inform a healthcare professional about all prescription and over-the-counter medicines, vitamins, and supplements being taken before starting Monurol.

Mechanism of Action

Irreversible Enzyme Inactivation and Structural Mimicry

This core mechanistic domain details the drug's molecular interaction: the active ingredient, fosfomycin, acts as a structural mimic of the natural bacterial substrate, phosphoenolpyruvate (PEP). It permanently binds to and irreversibly inactivates the bacterial enzyme MurA (UDP-N-acetylglucosamine-3-enolpyruvyltransferase), which is critical for the initial step of cell wall construction.

Peptidoglycan Pathway Blockade and Cell Lysis

The inactivation of the MurA enzyme halts the entire peptidoglycan synthesis pathway, leading to a complete failure in forming the essential bacterial cell wall. This defect results in a bactericidal effect because the weakened pathogen cannot withstand osmotic pressure, causing rapid cell destruction (lysis). This mechanism leads to the destruction of susceptible microbial populations.

Dosage and Administration Information

Monurol is administered through the oral route as single-dose granules for oral solution. The foundational usage pattern for uncomplicated acute cystitis involves the administration of a single 3-gram dose of fosfomycin. This fixed regimen defines the entire treatment course and is not repeated for a single infectious episode.

Preparation is a prerequisite for proper use. The full contents of the sachet must be thoroughly dissolved in a small amount of cold water, typically 3 to 4 ounces, and must be consumed immediately upon reconstitution. The product must never be taken in its dry, granular form. Instructions regarding the relationship to meals vary; while some protocols state the product may be taken with or without food, in other instances it is specified for administration on an empty stomach, preferably before bedtime and after bladder voiding.

Usage in other clinical scenarios, such as prophylaxis for certain urological procedures, involves a two-dose schedule: 3 grams taken three hours before the procedure and a second 3-gram dose taken 24 hours after.

Specific population constraints apply. The product is not recommended for use in children under 12 years of age, and its use is restricted in patients with severe renal impairment, generally defined as a creatinine clearance below 10 mL/min. The standard 3-gram dose typically requires no adjustment for older adults.

Recent Clinical Evidence

Research evidence / Overview of Studies for Monurol

The research available for fosfomycin tromethamine describes its evaluation through official studies and clinical trials, focusing on how the medicine was studied for conditions characterized by episodic or acute manifestations in the urinary tract. This overview summarizes the available research landscape, adhering strictly to what is officially documented and what remains uncertain.

Evidence for Use in Uncomplicated Acute Cystitis

The core evidence landscape for Monurol describes research conducted through numerous Randomized Controlled Trials (RCTs) and comprehensive Meta-Analyses. These studies, which often included comparisons to other standard multi-day antibiotic regimens, focused primarily on non-pregnant adult women and adolescent girls presenting with conditions involving periods of heightened symptoms, such as painful urination (dysuria), urinary urgency, and frequency.

Research was studied for short-term symptom changes. Studies monitored outcomes related to physical discomfort and outcomes reflecting daily functioning by measuring clinical outcome measurement—tracking the change or evolution of symptoms over defined time intervals. Trials also explored microbiological success, which examined whether the causative bacteria were cleared from the urine culture shortly after taking the medication.

Research in Special Clinical Scenarios

Monurol was evaluated in specific populations and clinical scenarios beyond the primary indication, where the evidence is limited compared to the core studies.

Research explored the microbiological success (clearance) of Monurol in pregnant women with Asymptomatic Bacteriuria (ASB). These studies involved trials focused on short-term bacterial clearance rates. Monurol was also observed in research contexts as a form of prophylaxis (a measure studied before or after procedures) before or after certain urological procedures. This data largely applies only to the populations studied, such as adult men undergoing transrectal prostate biopsy, and comparative evidence is lacking for certain urological contexts.

Evidence Gaps and Research Uncertainty

The follow-up durations used in the majority of core Monurol studies were limited, generally tracking outcomes for only a few weeks after administration. There is limited information for long-term outcomes regarding the recurrence of infection. Evidence is limited for using the standard oral formulation in many complicated urinary tract infections (UTIs). Subgroup findings are uncertain in some cases, and data for certain groups remain insufficient, including more detailed studies on older adults or patients with specific long-term health conditions.

Key Studies & References

Frequently Asked Questions (FAQ)

Common questions about Monurol (FAQ)

Q: How long after taking Monurol should a patient wait to feel better?

Official product information indicates that patients typically begin to notice an improvement in symptoms within 2 to 3 days after taking the single dose of Monurol. If symptoms do not improve as expected during this time, official information indicates that a healthcare professional should be consulted. This information reflects the documented timeline for clinical response following treatment.

Q: Can Monurol affect liver function tests?

Studies and official product information have occasionally reported generally transient increases in liver enzymes (such as ALT and AST) in patients taking Monurol. These enzyme changes, which are indicators of liver function, were usually not viewed as clinically significant. It is important to discuss any scheduled laboratory testing with a healthcare provider.

Q: What should be done if an allergic reaction is suspected after taking Monurol?

Regulatory patient information states that individuals should contact a doctor immediately if they experience any signs of a serious allergic or hypersensitivity reaction. Such signs could include the development of a rash, fever, joint pain, or swelling of the face, mouth, or tongue. These reactions are described as severe, and regulatory information advises seeking immediate medical attention.

Q: Is Monurol available over-the-counter in any country?

According to the official product prescribing information, Monurol (fosfomycin tromethamine) is designated as a prescription medication (Rx only) in the United States and other regions. This means it must be prescribed by a healthcare professional and is not available for purchase without a prescription.

Q: Is Monurol a sulfa drug?

No, Monurol is not classified as a sulfa drug (sulfonamide). The active ingredient, fosfomycin, is a synthetic antibiotic derived from phosphonic acid and belongs to a unique class of antibiotics. Official regulatory data indicates that this distinct structure generally means there is no cross-resistance with many other common classes of antibiotics.

Q: Does Monurol cause changes in blood sugar levels?

Official product information notes that the oral granules contain the excipient sucrose (sugar). Because of this ingredient, caution is advised for patients with diabetes or other conditions that require strict monitoring or limitation of dietary sugars. Individuals with these conditions should discuss the contents with their healthcare provider.

Q: Can Monurol affect the taste of food?

Changes in taste perception, known medically as dysgeusia or hypogeusia, have been reported in association with Monurol use. Regulatory reports note that these taste disturbances were primarily observed during postmarketing experience or in cases of overdose. This is listed among the possible adverse reactions of the medication.

Q: What if I vomit shortly after taking Monurol?

Regulatory patient information advises that if vomiting occurs soon after the dose is administered, the prescriber should be informed right away. This is because vomiting may affect the absorption of the single dose, and official information advises informing the prescriber right away for medical guidance.

Q: Is there a generic version of Monurol available?

Yes, regulatory bodies such as the FDA have approved generic versions of the active ingredient, fosfomycin tromethamine, for oral solution. This means that the active ingredient, fosfomycin tromethamine, has FDA-approved equivalents.

Q: Can Monurol be used by people with diabetes?

Official information advises caution and states that individuals who must limit sugar intake should discuss the contents with their healthcare provider, as the oral granule formulation contains a form of sugar (sucrose). The use of the medication should align with the patient's dietary needs for managing their condition.

Q: Is the side effect profile different for older vs younger patients?

Regulatory information indicates that the way the body handles the medicine is generally similar in older adults, and based on available data, no dosage adjustment is typically required. Regulatory labeling does not explicitly describe a separate frequency or profile of side effects based solely on age.

Q: Does Monurol have any known effects on the heart?

Regulatory reports based on postmarketing experience have occasionally noted certain effects, including tachycardia (a fast heart rate) and hypotension (low blood pressure). These are included among the possible adverse reactions associated with the use of the medicine.

Q: Does Monurol lose effectiveness if mixed with something other than water?

Official prescribing instructions specify that the contents of the sachet must be thoroughly dissolved only in 3 to 4 ounces of cold water. Regulatory documents do not provide instruction or data for mixing the granules with any liquids other than cold water.

How should Monurol be stored and disposed of?

Storage and Disposal of Monurol (Fosfomycin Tromethamine)

Official labeling requires Monurol granules to be stored at 25 C (77 F), with permitted temperature excursions between 15 C and 30 C (59 F and 86 F). The product must be protected from moisture and excessive heat, and should not be frozen. Keep the medicine in its original sachet until use.

After reconstitution in water, the solution is stable for 24 hours but should be taken immediately upon preparation. As a mandatory requirement, keep this and all medicines out of the sight and reach of children.

Any unused or expired Monurol must be disposed of according to local regulations or via a pharmaceutical take-back program. Do not throw the medicine into household trash or wastewater.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.