Formulary
Fosfomycin: Indications, Dosing, Side Effects and Interactions
Fosfomycin, a phosphonic acid antibacterial, is active against a range of Gram-positive and Gram-negative bacteria including Staphylococcus aureus and...
MedNext Academy | 5 min read
Fosfomycin: Indications, Dosing, Side Effects and Interactions
Fosfomycin, a phosphonic acid antibacterial, is active against a range of Gram-positive and Gram-negative bacteria including Staphylococcus aureus and...
Drug action
Fosfomycin, a phosphonic acid antibacterial, is active against a range of Gram-positive and Gram-negative bacteria including Staphylococcus aureus and Enterobacteriaceae.
Indications and dose
**Acute uncomplicated lower urinary-tract infections**
- **Adult** (By Mouth Using Granules): 3 g for 1 dose.
**Prophylaxis of urinary-tract infections in transurethral surgical procedures**
- **Adult** (By Mouth Using Granules): 3 g, to be given 3 hours before surgery. Dose may be repeated once, 24 hours after surgery.
**Osteomyelitis when first-line treatments are inappropriate or ineffective,Hospital-acquired lower respiratory-tract infections when first-line treatments are inappropriate or ineffective**
- **Adult** (By Intravenous Infusion): 12-24 g daily in 2-3 divided doses (max. per dose 8 g), use the high-dose regimen in severe infection suspected or known to be caused by less sensitive organisms.
**Complicated urinary-tract infections when first-line treatment ineffective or inappropriate**
- **Adult** (By Intravenous Infusion): 12-16 g daily in 2-3 divided doses (max. per dose 8 g).
**Bacterial meningitis when first-line treatment ineffective or inappropriate**
- **Adult** (By Intravenous Infusion): 16-24 g daily in 3-4 divided doses (max. per dose 8 g), use the high-dose regimen in severe infection suspected or known to be caused by less sensitive organisms.
**Acute uncomplicated lower urinary-tract infections (in females) for fosfomycin**
- **Child 12-17 years (female)** (By mouth using granules): 3 g for 1 dose.
**Osteomyelitis when first-line treatments are inappropriate or ineffective, Hospital-acquired lower respiratory-tract infections when first-line treatments are inappropriate or ineffective for fosfomycin**
- **Neonate up to 40 weeks corrected gestational age** (By intravenous infusion): 100 mg/kg daily in 2 divided doses.
- **Neonate 40 weeks to 44 weeks corrected gestational age** (By intravenous infusion): 200 mg/kg daily in 3 divided doses.
- **Child 1-11 months (body-weight up to 10 kg)** (By intravenous infusion): 200-300 mg/kg daily in 3 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 1-11 years (body-weight 10-39 kg)** (By intravenous infusion): 200-400 mg/kg daily in 3-4 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 12-17 years (body-weight 40 kg and above)** (By intravenous infusion): 12-24 g daily in 2-3 divided doses (max. per dose 8 g), use the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
**Complicated urinary-tract infections when first-line treatment ineffective or inappropriate for fosfomycin**
- **Neonate up to 40 weeks corrected gestational age** (By intravenous infusion): 100 mg/kg daily in 2 divided doses.
- **Neonate 40 weeks to 44 weeks corrected gestational age** (By intravenous infusion): 200 mg/kg daily in 3 divided doses.
- **Child 1-11 months (body-weight up to 10 kg)** (By intravenous infusion): 200-300 mg/kg daily in 3 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 1-11 years (body-weight 10-39 kg)** (By intravenous infusion): 200-400 mg/kg daily in 3-4 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 12-17 years (body-weight 40 kg and above)** (By intravenous infusion): 12-16 g daily in 2-3 divided doses (max. per dose 8 g), use the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
**Bacterial meningitis when first-line treatment ineffective or inappropriate for fosfomycin**
- **Neonate up to 40 weeks corrected gestational age** (By intravenous infusion): 100 mg/kg daily in 2 divided doses.
- **Neonate 40 weeks to 44 weeks corrected gestational age** (By intravenous infusion): 200 mg/kg daily in 3 divided doses.
- **Child 1-11 months (body-weight up to 10 kg)** (By intravenous infusion): 200-300 mg/kg daily in 3 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 1-11 years (body-weight 10-39 kg)** (By intravenous infusion): 200-400 mg/kg daily in 3-4 divided doses, consider using the high-dose regimen in severe infection, particularly when suspected or known to be caused by less sensitive organisms.
- **Child 12-17 years (body-weight 40 kg and above)** (By intravenous infusion): 16-24 g daily in 3-4 divided doses (max. per dose 8 g), use the high-dose regimen in severe infection suspected or known to be caused by less sensitive organisms.
Cautions
With intravenous use Cardiac insufficiency; elderly (high doses); hyperaldosteronism; hypernatraemia; hypertension; pulmonary oedema
Side effects
General side-effects: Common or very common Abdominal pain; diarrhoea; headache; nausea; vomiting Uncommon Skin reactions Frequency not known Antibiotic associated colitis; Clostridioides difficile colitis; pseudomembranous enterocolitis Specific side-effects: Common or very common With oral use Dizziness; vulvovaginal infection Uncommon With parenteral use Appetite decreased; dyspnoea; electrolyte imbalance; fatigue; oedema; taste altered; vertigo Rare or very rare With parenteral use Bone marrow disorders; eosinophilia; hepatic disorders; visual impairment Frequency not known With parenteral use Agranulocytosis; asthmatic attack; confusion; leucopenia; neutropenia; tachycardia; thrombocytopenia
Interactions
**Other interactions (1):**
- However, certain classes of antibiotics are more involved, particularly: fluoroquinolones, macrolides, cyclins, cotrimoxazole, and certain cephalosporins.
Pregnancy
Manufacturer advises use only if potential benefit outweighs risk.
Breast feeding
Manufacturer advises use only if potential benefit outweighs risk-present in milk.
Renal impairment
Prescribing in renal impairment . With oral use: Avoid if creatinine clearance less than 10 mL/minute. M With intravenous use: Caution if creatinine clearance 40-80 mL/minute; consult product literature if creatinine clearance less than 40 mL/minute. M
Medicinal forms
Solution,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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