Fosfomycin parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Infusions of fosfomycin.
Drugs List
Therapeutic Indications
Uses
Bacterial endocarditis
Bacterial meningitis
Complicated intra-abdominal infections: treatment
Complicated skin and soft tissue infections
Complicated urinary tract infections
Nosocomial lower respiratory tract infections
Osteomyelitis
Dosage
Fosfomycin infusion should only be used when it is considered inappropriate to use commonly recommended antibacterial agents for the initial treatment of the infections it is indicated for, or when the commonly recommended agents have failed to demonstrate efficacy.
Duration of treatment depends on individual response of the pathogens and the patient's clinical outcome. Therapy should be continued for a few more days after fever and other symptoms have subsided.
Adults
Individual doses must not exceed 8g.
The high-dose regimen in 3 divided doses should be used in severe infections expected or known to be caused by less susceptible bacteria.
At the time of writing, there are limited data for doses in excess of 16g per day. Caution is advised when such doses are prescribed.
Acute osteomyelitis
12 to 24g daily in 2 to 3 divided doses.
Complicated urinary tract infection
12 to 24g daily in 2 to 3 divided doses.
Nosocomial lower respiratory tract infection
12 to 24g daily in 2 to 3 divided doses.
Bacterial meningitis
16 to 24g daily in 3 to 4 divided doses.
Infective endocarditis
12 to 24g daily in 2 to 3 divided doses.
Complicated skin and soft issue infection
12 to 24g daily in 2 to 3 divided doses.
Complicated intra-abdominal infections
12 to 24g daily in 2 to 3 divided doses.
Elderly
(See Dosage; Adults). Use with caution if doses at the higher end of the recommended range are considered.
Children
Child doses should be based on age and body weight.
Children aged 12 to 18 years old
(See Dosage; Adults)
Children aged 1 to 12 years old with body weight of 10 to 40kg
200 to 400mg/kg body weight daily in 3 to 4 divided doses.
The high-dose regimen should be used in severe and/or serious infections, in particular when known or suspected to be caused by organisms with moderate susceptibility.
Children aged 1 to 12 months old with body weight up to 10kg
200 to 300mg/kg body weight daily in 3 divided doses.
The high-dose regimen should be used in severe and/or serious infections, in particular when known or suspected to be caused by organisms with moderate susceptibility.
Neonates
The ages listed are the sum of gestational and postnatal age.
Neonates aged 40 to 44 weeks
200mg/kg body weight daily in 3 divided doses
Premature neonates aged less than 40 weeks
100mg/kg body weight daily in 2 divided doses
Patients with Renal Impairment
Creatinine clearance 40 to 80ml/minute
Use with caution especially if doses at the higher end of the recommended range are considered. There are no dose reductions recommended.
Creatinine clearance 40ml/minute
70% of normal dose in 2 to 3 divided doses. The first dose should be increased by 100% (loading dose), but must not exceed 8g.
Creatinine clearance 30ml/minute
60% of normal dose in 2 to 3 divided doses. The first dose should be increased by 100% (loading dose), but must not exceed 8g.
Creatinine clearance 20ml/minute
40% of normal dose in 2 to 3 divided doses. The first dose should be increased by 100% (loading dose), but must not exceed 8g.
Creatinine clearance 10ml/minute
20% of normal dose in 1 to 2 divided doses. 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 at the end of each dialysis.
Fosfomycin is effectively eliminated during veno-venous haemofiltration (post-dilution CVVHF). Patients undergoing post-dilution CVVHF will not require any dose adjustment.
Administration
For intravenous administration only.
Contraindications
None known
Precautions and Warnings
Children under 12 years
Hypoalbuminaemia
Restricted sodium intake
Breastfeeding
Cardiac impairment
Hepatic cirrhosis
Hyperaldosteronism
Hypernatraemia
Hypertension
Nephrotic syndrome
Pregnancy
Pulmonary oedema
Renal impairment - creatinine clearance below 80ml/min
Reduce dose in patients with creatinine clearance of 10-40ml/min
Sodium content of formulation may be significant
Advise ability to drive/operate machinery may be affected by side effects
Consult national/regional policy on the use of anti-infectives
Low sodium diet recommended during treatment
Consider pseudomembranous colitis if patient presents with severe diarrhoea
Monitor haematological parameters regularly throughout treatment
Monitor serum electrolytes
May reduce serum potassium levels
Discontinue if hypersensitivity reactions occur
Discontinue therapy if marked diarrhoea occurs
In vitro, fosfomycin has been found to rapidly select for resistant mutants. Also, the use of intravenous fosfomycin alone has been associated with selection of resistance in clinical studies. Whenever possible, it is recommended that fosfomycin is administered as part of a combination antibacterial drug regimen to reduce the risk of selecting for resistance.
Serious and occasionally fatal hypersensitivity reactions, including anaphylaxis and anaphylactic shock, may occur. If such reactions occur, treatment with fosfomycin must be discontinued immediately and adequate emergency measures must be initiated.
Pregnancy and Lactation
Pregnancy
Use fosfomycin with caution during pregnancy.
The manufacturer advises caution if fosfomycin is used during pregnancy. Animal studies have not shown reproductive toxicity. At the time of writing, there is limited published information regarding the use of fosfomycin during pregnancy. Potential risks are unknown.
Fosfomycin is known to cross the placenta however Briggs (2015) suggests the risk to the foetus is low.
Schaefer (2015) suggests fosfomycin can be used in pregnancy for severe infections when antibiotics of choice in pregnancy cannot be used.
Lactation
Use fosfomycin with caution during breastfeeding.
The manufacturer advises fosfomycin is not recommended as the first choice for breastfeeding, particularly if breastfeeding a premature or newborn baby. Whilst fosfomycin is present in human breast milk, the quantity expressed is low. Effects on exposed infants are unknown.
Side Effects
Agranulocytosis
Alanine aminotransferase increased
Anaphylactic shock
Angioedema
Aplastic anaemia
Aspartate aminotransferase increased
Asthma
Cholestatic hepatitis
Confusion
Decreased appetite
Diarrhoea
Dysgeusia
Dyspnoea
Eosinophilia
Facial oedema
Fatigue
Granulocytopenia
Headache
Hepatic disorders (fatty changes)
Hepatitis
Hypernatraemia
Hypokalaemia
Increase in alkaline phosphatase
Jaundice
Leucopenia
Nausea
Neutropenia
Oedema
Pancytopenia
Phlebitis (injection site)
Pruritus
Pseudomembranous colitis
Rash
Retching
Stomach discomfort
Tachycardia
Thrombocytopenia
Urticaria
Vertigo
Visual disturbances
Vomiting
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: April 2021
Reference Sources
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Summary of Product Characteristics: Fomicyt 40mg/ml powder for solution for infusion. Kent Pharma UK Ltd. Revised October 2020.
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