Dosage and Administration
Fomicyt® (fosfomycin IV) 40mg/ml powder for solution for infusion is available in 2g and 4g presentations.
The daily dose of Fomicyt® is determined based on the indication, severity and site of the infection, susceptibility of the pathogen(s) to Fosfomycin IV and the renal function. In children, it is also determined by age and body weight.
The general dosage guidelines for adults with estimated creatinine clearance > 80ml/min are as follows:
| Indication | Daily dose |
|---|---|
| Complicated intra-abdominal infections | 12–24g a b in 2-3 divided doses |
| Infective endocarditis | 12–24g a b in 2-3 divided doses |
| Complicated skin and soft tissue infections | 12–24g a b in 2-3 divided doses |
| Complicated urinary tract infections | 12–24g a b in 2-3 divided doses |
| Hospital-acquired pneumonia, including ventilator – associated pneumonia | 12–24g a b in 2-3 divided doses |
| Bone and joint infections | 12–24g a b in 2-3 divided doses |
| Bacterial meningitis | 16–24g a b in 3-4 divided doses |
| Bacteraemia that occurs in association with, or is suspected to be associated with, any of the infections listed above | 12–24g a b in 2-3 divided doses |
a Dosing for adults and adolescents ≥ 12 years of age (≥ 40kg) with normal renal function (creatinine clearance > 80ml/min).
b The high-dose regimen (> 16g/day in 3 divided doses) should be used in severe infections expected or known to be caused by less susceptible bacteria. There is limited safety data in particular for doses in excess of 16g/day. Special caution is advised when such doses are prescribed.
Individual doses must not exceed 8g.
Dosage table for patients with impaired renal function:
| CLCR patient (ml/min) |
CLCR patient / CLCR normal |
Daily dose recommended (% of standard dose)a |
|---|---|---|
| 40 | 0.333 | 70% (in 2-3 divided doses) |
| 30 | C0.250 | 60% (in 2-3 divided doses) |
| 20 | 0.167 | 40% (in 2-3 divided doses) |
| 10 | 0.083 | 20% (in 2-3 divided doses) |
a The dose is expressed as a proportion of the dose that would have been considered appropriate if the patient’s renal function were normal.
The first dose should be increased by 100% (loading dose), but must not exceed 8g
Patients undergoing renal replacement therapy
Patients undergoing chronic intermittent dialysis (every 48 hours) should receive 2g of fosfomycin IV at the end of each dialysis session.
During continuous veno-venous hemofiltration (post-dilution CVVHF), fosfomycin IV is effectively eliminated. Patients undergoing post-dilution CVVHF will not require any dose adjustment.
The dosage of Fomicyt® (fosfomycin IV) in children should be based on age and body weight (BW):
| Age/weight | Daily Dose |
|---|---|
| Premature neonates (age<40 weeks)a | 100mg/kg in 2 divided doses |
| Neonates (age 40-44 weeks)a | 200mg/kg in 3 divided doses |
| Infants 1-12 months (up to 10kg bodyweight) | 200-300mg/kg in 3 divided dosesb |
| Infants and children aged 1-12 years (10-40kg bodyweight) | 200-400mg/kg in 3-4 divided dosesb |
a Sum of gestational and postnatal age
b The high-dose regimen may be considered for severe infections and or serious infections (such as meningitis), in particular when known or suspected to be caused by organisms with moderate susceptibility.
Treatment duration 1
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.
Note:
1g Fomicyt® (equivalent to 1.32g disodium fosfomycin) contains 14mmol (320mg) sodium, equivalent to 16% of the WHO recommended maximum daily dietary intake of 2g sodium for an adult. One bottle with 2g of fosfomycin contains 28mmol (640mg) sodium, one bottle with 4g fosfomycin contains 56mmol (1280mg) sodium.
A high sodium load associated with the use of Fomicyt® 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 with Fomicyt®.
Preparation of the solution for infusion1
FOMICYT® must be reconstituted and diluted prior to administration.
Water for Injections and Glucose Infusion 50mg/ml (5%) or Glucose Infusion 100mg/ml (10%) may be used as solvent for the reconstitution and dilution. Sodium chloride containing solvents must not be used.
Reconstitution
Shake the vial prior to the reconstitution to loosen up the powder. Reconstitute the 2g or 4g vials with 20ml of solvent. Shake well to dissolve. A slight degree of warming 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 2g vials into an infusion container with further 30ml of solvent.
Transfer the reconstituted contents of 4g vials into an infusion container with further 80ml of solvent.
The resulting solution for infusion is clear and colourless to slightly yellowish.
Displacement value
The displacement values for the solutions are 1ml for the 2g pack size and 2ml for the 4g pack size.
These volumes are equivalent to an increase of volume of 2%. This has to be considered when not the entire volume of the final diluted solution is used.
