Sanofos IV Dosage/Direction for Use

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.