Sanofos IV

Fosfomycin sodium.

Each vial contains Fosfomycin Sodium equivalent to Fosfomycin 2.0 g or 4.0 g, respectively.
Excipients/Inactive Ingredients: Succinic acid.

Pharmacotherapeutic group: Antibiotics for systemic use, other antibacterials. ATC-Code: J01XX01.
Pharmacology: Pharmacodynamics: Mode of action: Fosfomycin exerts a bactericidal effect on proliferating pathogens by preventing the enzymatic synthesis of the bacterial cell wall. Fosfomycin inhibits the first stage of intracellular bacterial cell wall synthesis by blocking peptidoglycan synthesis.
Fosfomycin is actively transported into the bacterial cell via two different transport systems (the sn-glycerol-3-phosphate and hexose-6 transport systems).
Pharmacokinetic (PK)/pharmacodynamic (PD) relationship: Limited data indicate that fosfomycin most likely acts in a time-dependent manner.
Resistance mechanism: Main mechanism of resistance is a chromosomal mutation causing an alteration of the bacterial fosfomycin transport systems. Further resistance mechanisms, which are plasmid- or transposon-borne, cause enzymatic inactivation of fosfomycin by binding the molecule to glutathione or by cleavage of the carbon-phosphorus-bond in the fosfomycin molecule, respectively.
Cross-resistance: The mode of action of fosfomycin differs from that of all other antibiotic classes. Fosfomycin was generally found to be active in-vitro against clinical isolates of methicillin-resistant staphylococci, vancomycin-resistant enterococci, penicillin and erythromycin-resistant streptococci and multiresistant Pseudomonas.
Antimicrobial spectrum of fosfomycin (in vitro): The data predict only the probability of micro-organism susceptibility to fosfomycin.
For intravenous fosfomycin, the susceptibility breakpoints established by the European Committee on Antimicrobial Susceptibility Testing are as follows (EUCAST breakpoint table version 5.0, 2015). (See Table 1.)

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The prevalence of acquired resistance of individual species may vary geographically and over time. Local information about the resistance situation is therefore necessary, particularly in order to ensure appropriate treatment of severe infections.
In-vitro activity spectrum of fosfomycin and resistance: The following table is based on the breakpoint according to EUCAST and comprises organisms relevant for the approved indications: See Table 2.

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The physiologically important apathogenic anaerobic species, Lactobacillus and Bifidobacterium, are not susceptible to fosfomycin.
Pharmacokinetics: A single intravenous infusion of 4 g of fosfomycin in young healthy males resulted in maximum serum concentration (Cmax) of approx. 200 μg/ml. The serum half-life was approx. 2 hours.
Distribution: The apparent volume of distribution of fosfomycin is approx. 0.30 l/kg body weight. Fosfomycin is distributed well to tissues. High concentrations are reached in eyes, bones, wound secretions, musculature, cutis, subcutis, lungs and bile. In patients with inflamed meninges, cerebrospinal fluid concentrations reach approx. 20-50% of the corresponding serum levels. Fosfomycin passes the placental barrier. Low quantities were found in human milk (about 8% of the serum concentrations). The plasma protein binding is negligible.
Metabolism: Fosfomycin is not metabolised by the liver and does not undergo enterohepatic circulation. No accumulation is therefore to be expected in patients with hepatic impairment.
Elimination: 80-90% of the quantity of fosfomycin administered to healthy adults is eliminated renally within 10 hours after a single intravenous administration. Fosfomycin is not metabolized, i.e. the biologically active compound is eliminated. In patients with normal or mildly to moderately impaired renal function (creatinine clearance ≥ 40 ml/min), approximately 50-60% of the overall dose is excreted within the first 3-4 hours.
Linearity: Fosfomycin shows linear pharmacokinetic behaviour after intravenous infusion of therapeutically used doses.
Special populations: Very limited data are available in special populations.
Elderly: No dose adjustment is necessary based on age alone. However, renal function should be assessed and the dose should be reduced if there is evidence of renal impairment (see Dosage & Administration).
Paediatric population: The pharmacokinetics of fosfomycin in children and adolescents aged 3-15 years as well as in term newborns with normal renal function are generally similar to those of healthy adult subjects. However, in renally healthy neonates and infants up to 12 months, the glomerular filtration rate is physiologically decreased compared to older children and adults. This is associated with a prolongation of the elimination half-life of fosfomycin in dependence on the stage of renal maturation.
Renal insufficiency: In patients with impaired renal function, the elimination half-life is increased proportionally to the degree of renal insufficiency. Patients with creatinine clearance values of 40 ml/min or less require dose adjustments (see also Dosage in renal insufficiency under Dosage & Administration for further details).
In a study investigating 12 patients under CVVHF customary polyethylene sulfone haemofilters with a membrane surface of 1.2 m² and a mean ultrafiltration rate of 25 ml/min were employed. In this clinical setting, the mean values of plasma clearance and elimination half-life in plasma were 100 ml/min, and 12 h, respectively.
Hepatic insufficiency: There is no requirement for dosage adjustments in patients with hepatic insufficiency since the pharmacokinetics of fosfomycin remains unaffected in this patient group.
Toxicology: Preclinical Safety data: Subacute and chronic toxicity: The toxicity of Fosfomycin following repeated administration for up to 6 months was evaluated in rats, dogs, rabbits and monkeys. At high intra-peritoneal doses of Fosfomycin (> 500 mg/kg/day), rats developed respiratory arrest, tetanic cramps, anemia, a reduction of blood protein levels, increased serum cholesterol and reduced blood glucose. Furthermore, dogs and monkeys experienced diarrhea due to antibiotic-related changes in the intestinal flora following intravenous administration of doses higher than 250 mg/kg/day and 500 mg/kg/day, respectively. In the rabbit, no toxicity was observed following intravenous administration of 400 mg/kg/day for a period of 1 month.
Reproductive toxicity: Fertility: In male and female rats, following repeated administration (via a pharyngeal tube) of up to 1400 mg/kg/day reduced fertility was observed at the maximum dose tested.
Teratogenicity: Fosfomycin was administered to mice, rats and rabbits via pharyngeal tube at maximum doses of 2 x 120 mg/kg/day, 1400 mg/kg/day and 420 mg/kg/day, respectively or intravenously to mice and rabbits at 55.3 mg/kg/day, and up to 250 mg/kg/day, respectively. There was no evidence of embryotoxicity or teratogenicity.
Perinatal and postnatal toxicity: In rats, a maximum dose of 2800 mg/kg/day was administered via a pharyngeal tube. There was no evidence of fetal or peri- and postnatal toxicity.
Mutagenicity: In-vitro tests were performed to test the alkylating capacity and the mutagenic effect of Fosfomycin. Fosfomycin showed no alkylating effect. In the Ames test, no mutagenic effect was seen in test strains of Salmonella typhimurium (TA 98, TA 100, TA 1535, TA 1537 and TA 1538, with and without addition of rat-liver homogenate) after exposure Fosfomycin at up to 1600 μg/ml.

Fosfomycin is indicated for the treatment of the following infections in adults and children including neonates (see Pharmacology: Pharmacodynamics under Actions): Osteomyelitis; Complicated urinary tract infections; Nosocomial lower respiratory tract infections; Bacterial meningitis; Bacteraemia that occurs in association with, or is suspected to be associated with, any of the infections listed previously.
Fosfomycin should be used only when it is considered inappropriate to use antibacterial agents that are commonly recommended for the initial treatment of the infections listed previously, or when these alternative antibacterial agents have failed to demonstrate efficacy.
For information regarding the combination with other antibiotics see Precautions and Interactions.
Consideration should be given to official guidance on the appropriate use of antibacterial agents.

The daily dose of fosfomycin is determined based on the indication, severity and site of the infection, susceptibility of the pathogen(s) to fosfomycin and the renal function. In children, it is also determined by age and body weight.
Adults and adolescents > 12 years of age (> 40 kg): Fosfomycin is primarily excreted renally unchanged. The general dosage guidelines for adults with estimated creatinine clearance > 80 ml/min are as follows: See Table 3.

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Dosage in renal insufficiency: The dose recommendations for patients with renal impairment are based on pharmacokinetic modelling and limited clinical data; safety and efficacy have not yet been evaluated in clinical trials.
It is unclear if dose reductions are necessary for patients with an estimated creatinine clearance between 40-80 ml/min. Great caution should be exercised in these cases, particularly if doses at the higher-end of the recommended range are considered.
In patients with impaired renal function the dose of fosfomycin must be adjusted to the degree of renal impairment. Dose titration should be based on creatinine clearance values. In adults, creatinine clearance may be calculated according to the following formula by Cockroft and Gault: See Equation.

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In order to calculate CL_CR in women, the result of this formula is multiplied by 0.85.
Dosage table for patients with impaired renal function: See Table 4.

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Patients undergoing renal replacement therapy: Patients undergoing chronic intermittent dialysis (every 48 hours) should receive 2 g of fosfomycin at the end of each dialysis session.
During continuous veno-venous hemofiltration (post-dilution CVVHF), fosfomycin is effectively eliminated. Patients undergoing post-dilution CVVHF will not require any dose adjustment (see Pharmacology: Pharmacokinetics under Actions).
No clinical data exist for intravenous Fosfomycin in patients undergoing pre-dilution CVVHF or other forms of renal replacement therapy.
Hepatic impairment: There are no data indicating that dose adjustment is necessary in patients with hepatic impairment.
Elderly patients: The recommended doses for adults should be used in elderly patients. Caution is advised when considering the use of doses at the higher end of the recommended range (see also recommendations on dosage for patients with impaired renal function).
Paediatric population: Dose recommendations are based on very limited data.
Neonates, infants and children < 12 years of age (<40 kg): The dosage of fosfomycin in children should be based on age and body weight (BW): See Table 5.

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Method and duration of administration: Method of administration: Fosfomycin is intended for intravenous administration. The duration of infusion should be at least 15 minutes for the 2 g pack size, at least 30 minutes for the 4 g pack size.
Use only clear solutions.
As damaging effects can result from inadvertent intra-arterial administration of product not specifically recommended for intra-arterial therapy, it is essential to ensure that Fosfomycin is only administered in veins.
For preparation of the solution for infusion see Special precautions for disposal and other handling under Cautions for Usage.
Duration of treatment: Treatment duration should take into account the type of infection, the severity of the infection as well as the patient's clinical response. Relevant therapeutic guidelines should be adhered to when deciding treatment duration.

Experience regarding the overdose of fosfomycin is limited. Cases of hypotonia, somnolence, electrolyte disturbances, thrombocytopenia and hypoprothrombinemia have been reported with parenteral use of fosfomycin. In the event of overdose, the patient must be monitored (particularly for plasma/serum electrolyte levels), and treatment should be symptomatic and supportive. Rehydration is recommended to promote urinary elimination of the drug. Fosfomycin is effectively cleared from the body by haemodialysis with a mean elimination half-life of approximately 4 hours.

Hypersensitivity to the active substance, fosfomycin, or to any of the excipients listed in Description.

Consideration should be given to co-administering intravenous fosfomycin with another antibacterial agent, taking into account the remaining susceptibilities of the pathogen(s) under treatment. As it is unknown whether the development of antibacterials should also be considered in order to prevent the emergence of resistance.
A high sodium load associated with the use of fosfomycin may result in decreased levels of potassium in serum or plasma. A low-sodium diet is recommended during treatment. The substitution of potassium may be necessary in some cases. Serum electrolyte levels and water balance must be monitored during therapy. Caution is advised when fosfomycin is used in patients with cardiac insufficiency, hypertension, hyperaldosteronism, hypernatraemia or pulmonary oedema. During prolonged treatment with high doses, blood potassium levels should be monitored in particular in digitalized heart failure patients (possible hypokalaemia, see Adverse Reactions).
Acute, potentially life-threatening hypersensitivity reactions (anaphylactic shock) may occur in very rare cases. At the first signs (including sweating, nausea, cyanosis), the infusion of fosfomycin must be immediately discontinued. The intravenous line should be left in place. Depending upon the clinical situation, appropriate emergency measures may need to be initiated.
Antibacterial agent-associated colitis and pseudo-membranous colitis have been reported with nearly all antibacterial agents including fosfomycin, and may range in severity from mild to life-threatening. Therefore, it is important to consider this diagnosis in patient who present with diarrhoea during or subsequent to the administration of fosfomycin.
Discontinuation of therapy with fosfomycin and the administration of specific treatment for Clostridium difficile should be considered. Medicinal products that inhibit peristalsis should not be given.
In patients with severe renal insufficiency (creatinine clearance ≤ 40 ml/min), the elimination of fosfomycin is substantially slowed. See Dosage & Administration for appropriate dosing of fosfomycin in renal insufficiency.
Effects on ability to drive and use machine: Occasionally, even if the product is correctly administered, side effects may occur which impair the ability to drive and use machines (see also Adverse Reactions).

Pregnancy: For fosfomycin, no clinical data on pregnancies are available. Animal studies do not indicate direct or indirect harmful effects with respect to pregnancy, embryonal/foetal development, parturition or postnatal development (see Pharmacology: Toxicology: Preclinical Safety data under Actions).
Fosfomycin should therefore not be prescribed to pregnant women unless the benefit outweighs the risk.
Lactation: After the administration of fosfomycin, low quantities of fosfomycin were found in human milk. Fosfomycin should therefore not be administered during lactation, unless the benefit outweighs the risk.

Summary of the safety profile: The most commonly reported adverse reactions during treatment are gastrointestinal disturbances and injection site reactions. Other important adverse reactions include hypokalaemia and/or hypernatraemia.
Tabulated list of adverse reactions: Undesirable effects are listed by body system and frequency in accordance with the following classification: Very common: ≥ 1/10; Common: ≥ 1/100 to < 1/10; Uncommon: ≥ 1/1,000 to < 1/100; Rare: ≥ 1/10,000 to < 1/1,000; Very rare: < 1/10,000; Not known: cannot be estimated from the available data. (See Table 6.)

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Description of selected adverse reactions: Hypokalaemia may result in diffuse symptoms such as weakness, tiredness or oedema and/or muscle twitching. Severe forms may cause hyporeflexia and cardiac arrhythmia. Hypernatraemia may be associated with hypertension and signs of fluid overload such as oedema (see Precautions).
Paediatric population: Limited safety information is available from the paediatric population. Frequency, type and severity of adverse reactions may be expected to be similar to the adult population.

No drug-drug interaction studies have been performed with Fosfomycin. To date, no clinically relevant pharmacological interactions between fosfomycin and other agents (drugs, stimulants or foodstuff) have been reported.

Incompatibilities: Although no chemical/pharmaceutical incompatibilities have been found, Sanofos IV solutions should not be mixed together with other parenteral preparations with the exception of those listed in Shelf-life under Storage.
Special precautions for disposal and other handling: For single use only.
Any unused product or waste material should be disposed of in accordance with local requirements.
Preparation of the solution for infusion: Water for Injection and 5% Dextrose in water or 10% Dextrose in water may be used as solvent for the reconstitution and dilution has been demonstrated in-use stability report. Sodium chloride containing solvent must not be used (see Precautions).
Reconstitution: Shake the vial prior to the reconstitution to loosen up the powder. Reconstitute the 2 g or 4 g vials with 20 ml of solvent. Shake well to dissolve. A slight degree of warning occurs when the powder is dissolved.
Caution: This intermediate solution is not for direct infusion. Withdraw the solution completely from the original vial. Transfer the withdrawn solution into an infusion bag or other suitable infusion container for further dilution as follows.
Dilution: Transfer the reconstituted contents of 2 g vials into an infusion container with further 30 ml of solvent.
Transfer the reconstituted contents of 4 g vials into an infusion container with further 80 ml of solvent.
The resulting solution for infusion is clear and colourless to slightly yellowish.

Store below 30°C.
Shelf-life: 2 years.
Chemical and physical in-use stability of the final diluted solution that has been produced under aseptic conditions has been demonstrated for 24 hours at 30°C.
For a microbiological point of view, the product should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 2 to 8°C, unless preparation has taken place in controlled and validated aseptic conditions.

Other Antibiotics

J01XX01 - fosfomycin ; Belongs to the class of other antibacterials. Used in the systemic treatment of infections.

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